Category Archives: General Horticulture/Weeds

Beginning Vegetable Garden Basics: Site Selection and Soil Preparation

Starting a vegetable garden may seem overwhelming to a first-time gardener.  However, learning gardening basics and being successful in gardening endeavors can be quite easy.  This fact sheet focuses on how novice gardeners can select and prepare their garden site to ensure maximum success.

Careful site selection and planning can help you maximize your gardening success.
Careful site selection and planning can help you maximize your gardening success.

Where should I plant my garden?  Most vegetables require full sun (i.e., at least six hours of direct sunlight) each day.  Watch a potential garden site throughout the growing season to make sure that trees or buildings do not shade the area from late morning through the afternoon.  A garden area should be well drained; water should not puddle or significantly flow through the area during heavy rains.   Avoid low spots where frost might settle in late spring or early fall, and steep slopes where runoff or erosion could occur.  Be sure the area has a convenient water source (e.g., access to a hose) so that you can water during dry spells.  DO NOT locate a garden within the root zone of black walnut trees.  These trees produce chemicals (juglones) that interfere with the growth of many vegetables.  See University of Wisconsin Garden Facts XHT1017, Black Walnut Toxicity, for details.  Keep in mind that the roots of a tree can grow three to five times the height of a tree away from the trunk.  Finally, make sure there are no underground utility lines where you plan to garden.

How big should my garden be?  Plan the size of your garden based on what you want to grow.  Crops like beans, beets, herbs, lettuce, onions, potatoes, radishes, squash and tomatoes are good options for first-time gardeners.  Start small with just a few crops that are easy to grow and care for.  Research (e.g., online, in seed catalogs, etc.) how large your selected vegetables will grow, and plan enough garden space so that they are not crowded.  Proper spacing promotes good air circulation and sunlight exposure.  Crowded plants will be less productive, difficult to maintain, and more susceptible to diseases.  Consider using bush varieties of vining crops like squash as these take much less space than vining varieties.  Tomato plants should not touch each other when fully mature and should be trellised to prevent crowding.  Cucumbers and smaller-fruited squash can also be trellised to improve spacing.  Space vegetables like beans, carrots and radishes that are seeded in rows according to the instructions on their seed packets.

When planning your garden, consider drawing a map to scale using graph paper to be sure you have enough space for your plants.   See Extension bulletin A1989, The Vegetable Garden, available at https://learningstore.extension.wisc.edu, to learn more on garden mapping, as well as about space requirements for many common vegetables.

Adding compost can improve the structure and fertility of most garden soils.
Adding compost can improve the structure and fertility of most garden soils.

How do I prepare my garden soil?  Ideally, start preparing your garden site the year before planting.  Remove any existing vegetation from your garden site (particularly grass).  You do not want this to grow back in your garden later.  A sod cutter (available to rent in most locations) can be useful for removing grass.  Alternatively, if the garden area is small enough, you can remove grass by hand using a shovel.  Be sure to collect any excess soil from the dug sod and return it to your garden.  After removing whatever vegetation you can, cover the area with cardboard, a tarp or black plastic to smother out any remaining vegetation that you have not been able to remove.

Once your garden area has been cleared of vegetation, add compost to improve the overall soil structure.  Compost helps sandy soils hold more moisture and nutrients, and it makes clay soils lighter and better drained.  Compost also adds trace nutrients needed by plants.  Work a two to three inch layer of compost into the soil with a rototiller or shovel at least a month prior to planting.  Smooth the surface so that you are ready to plant when the weather is appropriate.

Also, consider having the soil in your garden nutrient tested through a certified lab before planting.  A soil test will provide information on the type of soil, the soil pH, the amount of organic matter, and the levels of phosphorous and potassium.  The optimal pH for a vegetable garden is around 6.5, although most vegetables will grow very well with a pH anywhere between 6.0 and 7.2.  A good soil-testing lab will also give you specific recommendations of what to add to your soil to adjust the pH and improve nutrient levels to grow vegetables more successfully.  If you do not have time to test the soil before planting, you can submit a sample later and still make amendments.  However, amending soil after planting is more challenging.

For more information on site selection and soil preparation for vegetable gardens:  Contact your county Extension agent.

Milkweed (Ornamental Plants Toxic to Animals)

Milkweed (Asclepias spp.) is a group of common herbaceous ornamentals that are an essential food source for caterpillars of the monarch butterfly (Danaus plexippus).  To increase monarch populations, people are increasingly planting ornamental types of milkweed and encouraging common milkweed to grow wherever it occurs in uncultivated areas.  While milkweed is beneficial to monarch populations, people need to be aware that it is toxic and can be lethal to animals, particularly horses and other equines.

Common milkweed (left) is often grown as an ornamental because it is an important food source for monarch butterflies (right).  Unfortunately, the plant produces compounds that are toxic to many animals, particularly horses.  Photos courtesy of Nancy Braschler (left) and PJ Liesch (right).
Common milkweed (left) is often grown as an ornamental because it is an important food source for monarch butterflies (right). Unfortunately, the plant produces compounds that are toxic to many animals, particularly horses. Photos courtesy of Nancy Braschler (left) and PJ Liesch (right).

What does milkweed look like?  Common milkweed (Asclepias syriaca) grows two to five feet tall and has broad, oval leaves that are five to nine inches long.  The leaves are smooth on top and somewhat velvety on the undersides.  Flowers, appearing in mid-summer, are pink to purplish and form rounded umbels (i.e., flower clusters).  Common milkweed produces prickly, four to six-inch long seedpods filled with brown to black seeds connected to silky white tufts that help the seeds float on air currents when they are released.

Other commonly planted milkweeds include swamp milkweed (Asclepias incarnata) and butterfly weed (Asclepias tuberosa).  Swamp milkweed grows three to six feet tall, has narrower, oval leaves (with a distinct pointed tip) and produces pink or purple flowers.  Butterfly weed grows one to two and a half feet tall, has narrow, pointed-tipped leaves that tend to be hairier than those of common milkweed, and produces yellow, orange or red flowers.  Several other species of milkweeds are found in Wisconsin, including whorled milked (Aesclepias verticillata), a white-flowered species that is particularly toxic and commonly found in pastures.

Why should I be concerned about milkweed?  The milky white sap that oozes from the broken stems and leaves of many types of milkweed is a latex that contains high concentrations of steroid derivatives called cardenolides (specifically cardiac glycosides).  These compounds are present both in live plants and in dried milkweed (which can sometimes be found in baled hay or in pastures after a plant is cut or dies).  Cardiac glycosides disrupt proper muscle (including the heart) and kidney function, the nervous system and the body’s acid-base balance.  While horses and other equines are most at risk for milkweed poisoning, all animals including chickens, cattle, sheep, dogs, cats, and even humans, as well as some insects, are susceptible to milkweed toxins.

Interestingly, monarchs cannot break down cardenolides and accumulate these compounds within their bodies.  The stored cardenolides give monarchs a bitter taste, making them unattractive to predators.

How will I know if my animals have been poisoned by milkweed?  Common symptoms of milkweed/cardenolide poisoning include depression; salivation; dilated pupils; weak, rapid pulse; labored breathing; loss of muscle control; muscle spasms due to not eating; convulsions; collapse and death.  Lethal doses of cardenolide occur at 0.05% of an animal’s body weight when dry plant material is eaten and 2% of body weight when fresh plant material is consumed.  For an adult horse, eating 2.2 lb of cardenolide is a lethal dose.  Death typically occurs approximately eight to 10 hours after ingestion.  If you suspect cardenolide poisoning, give affected animals fresh, non-contaminated food and immediately contact your veterinarian.

How do I prevent milkweed poisoning?  Inspect pastures and hay fields regularly for wild milkweed plants, and remove any you find promptly.  Because dried milkweed also contains toxins, do not feed animals hay that contains milkweed.  Provide adequate, good-quality forage for your animals.  DO NOT assume that horses and other livestock will not eat milkweed.

Swamp milkweed (left) and butterfly weed (right) are two other common milkweed species grown in home gardens.  Photos courtesy of Bridget Kelley (left) and Deb Andazola (right).
Swamp milkweed (left) and butterfly weed (right) are two other common milkweed species grown in home gardens. Photos courtesy of Bridget Kelley (left) and Deb Andazola (right).

If you are growing milkweed as an ornamental, DO NOT plant it near pastures or fence lines where livestock could potentially reach the plants.  Dispose of any milkweed plants that are removed during routine garden cleanup in a location far removed from livestock, so that animals are not able to feed on the dead plants

Milkweed spreads by underground rhizomes and through windborne seeds.  This can make proper management a challenge.  Herbicides can be effective for control, if you apply them at the correct time.  See UW Bulletin A3646, Pest Management in Wisconsin Field Crops (available at https://learningstore.extension.wisc.edu/) for products available for use in pasture settings.  When using herbicides, be sure to follow all label instructions to ensure that you are using the product in the safest and most effective manner possible and limit any adverse livestock exposures.

For more information on milkweed:  Contact your county Extension agent.

Growing Vegetables in Containers

Container gardening is an increasingly popular way for home gardeners to grow their favorite vegetables, particularly when gardening space is limited.  Containers can be placed on a windowsill, patio, deck or balcony, or in any place where growing conditions are appropriate for producing vegetables.  Containers can be easily moved from place to place to take advantage of changing weather conditions (e.g., rain, sunlight), and their proximity to a home makes caring for plants and harvesting vegetables easy and convenient.  The following are some pointers on how to ensure success when container gardening.

Containers are a convenient place to grow your favorite vegetables and herbaceous ornamentals.
Containers are a convenient place to grow your favorite vegetables and herbaceous ornamentals.

What types of vegetables can I grow in containers?  Almost any vegetable can be grown in a container given the right variety and container size.  However, determinate, dwarf and compact vegetable varieties often work best.  Vegetables like arugula, kale, lettuce and spinach work well in containers because they are easy to seed, can be harvested frequently, and can be replanted throughout the season.  Smaller vegetables such as beets, carrots, radishes and turnips also grow well in containers because the loose, well-drained potting mixes used for container gardening allow roots to grow easily.  When growing root vegetables, be sure to space plants two to four inches apart to allow roots to form properly.  As an added bonus, the greens of root vegetables are not large, do not need support, and are very attractive.  Vining plants like cucumber, peas, melons and squash can be grown in containers with proper supports (e.g., trellises).  Alternatively, there are bush or hanging varieties of these vegetables that do well in containers.  Tomatoes (properly staked or caged), peppers, and eggplant grow especially well in containers and can be mixed with herbs or flowers for added visual appeal.  For a list of suggested vegetables for containers, see University of Wisconsin Garden Facts XHT1273, Vegetable Varieties for Containers.

What sort of container should I use?  Choosing the right type of container for the vegetables that you decide to grow is very important.  Containers should have the right volume and depth to support plants once they are fully grown.  In general, smaller plants like leaf lettuce, spinach, peas, radishes, cilantro, and green onions require containers with a volume of at least two gallons and that are at least four to six inches deep.  Larger plants like tomatoes, peppers, broccoli, eggplants, squash, cucumbers and bush beans require a container with a minimum volume of five gallons and a depth of 12 to 18 inches.  Many types of containers are available for growing vegetables including (but not limited to) 5-gallon plastic buckets, plastic pots, plastic storage containers, terra cotta/clay and ceramic pots, concrete and wooden planter boxes, wooden barrels, bushel baskets, plastic bags, grow bags and self-watering containers.  Make sure that the container you select has a drainage hole.

If you are reusing containers, be sure to decontaminate them prior to use, particularly if you previously have had problems with root rots (see University of Wisconsin Garden Facts XHT1072, Root Rots in the Garden) or damping-off (see University of Wisconsin Garden Facts XHT1124, Damping-Off).  Rinse pots to remove clinging bits of soil, then soak them in 10% bleach (a formulation designed to disinfect) for 30 minutes.  Then rinse containers to remove any bleach residue.  This treatment may not consistently be effective for plastic containers.  You may have to replace these containers if disease issues persist.

What sort of soil should I use?  Commercial potting mixes work well for most vegetables.  They are typically light weight, high in organic matter and well-drained, containing a combination of compost, peat moss, bark, perlite or other similar materials.  Read the label before purchasing a potting mix to determine its composition.  When possible, select a product that has been pasteurized to reduce the risk of diseases caused by soil-borne pathogens.  Consider adding a slow-release fertilizer, if there is not one included in the mix.  Bagged potting mixes come in easy-to-handle sizes:  1, 2, or 2.8 cubic feet (7.5, 15 and 21 gallons respectively).  Fill your container completely with planting mix for optimal drainage.  DO NOT put anything (e.g., rocks, broken pot pieces, etc.) in the bottom of the pot.  Research shows layering materials in a container impedes drainage; water moves best through a continuous column of soil mix.

Leafy vegetables like kale are easy to seed in containers, can be harvested frequently, and can be reseeded throughout the season.
Leafy vegetables like kale are easy to seed in containers, can be harvested frequently, and can be reseeded throughout the season.

How do I care for my plants?  Place your containerized plants in full sun (i.e., a minimum of six hours per day) with easy access to water.  Initially, when plants are small, you will not need to water much.  However, as plants increase in size, the temperature increases, and the plants start to produce fruit (e.g., tomatoes, peppers, eggplants, zucchinis, cucumbers), you will need to water daily.  You may also need to fertilize.  If so, use a fertilizer designed for growing vegetables, and follow the instructions on the label to determine how much and how frequently to apply.  Harvest leafy greens such as kale, mustard and lettuce on a regular basis, and reseed as needed.  If plants fail, remove and replace them with other vegetables that fit the space and have time to grow to harvest.  Greens, radishes, bush beans, and cilantro are fast-growing filler vegetables that you can grow from seed.

For more information on growing vegetables in containers:  See University of Wisconsin Garden Facts XHT1273, Vegetable Varieties for Containers or contact your county Extension agent.

Vegetable Varieties for Containers

Growing plants in containers (referred to as container gardening) is an easy way to grow and maintain vegetables.  Vegetables grown in containers can easily fit on a window sill, balcony, deck, door step or any other place where space is limited but where environmental conditions are suitable for vegetable production.

The list below contains recommendations on varieties of popular vegetables that are well-suited for growing in containers.

Click the vegetable names to expand the panel and view the variety info. The panel expands downward.

To close the expanded panel, click the vegetable name below it.
[accordion]

[accordion-item autoclose=”true” clicktoclose=”true” title=”Bean” class=”Bean”]

  • ‘Derby’
  • ‘Eureka’
  • ‘Mascotte’
  • ‘Porch Pick’
  • ‘Tendercrop’
  • ‘Topcrop’

[/accordion-item]

[accordion-item autoclose=”true” clicktoclose=”true” title=”Beet” class=”Beet”]

  • ‘Burpee’s Golden’
  • ‘Chioggia’
  • Detroit Dark Red Medium Top’
  • ‘Ruby Queen’

[/accordion-item]

[accordion-item autoclose=”true” clicktoclose=”true” title=”Carrot” class=”Carrot”]

  • ‘Danver’s Half Long’
  • ‘Little Finger’
  • ‘Nantes Half Long’
  • ‘Paris Market’
  • ‘Yaya’

[/accordion-item]

[accordion-item autoclose=”true” clicktoclose=”true” title=”Cucumber” class=”Cucumber”]

  • ‘Bush Champion’
  • ‘Bush Pickle’
  • ‘Iznik’
  • ‘Parisian Gherkin’
  • ‘Patio Snacker’
  • ‘Salad Bush’
  • ‘Saladmore Bush’
  • ‘Space Master’
  • ‘Sugar Crunch’

[/accordion-item]

[accordion-item autoclose=”true” clicktoclose=”true” title=”Eggplant” class=”Eggplant”]

  • ‘Dusky’
  • ‘Early Midnight’
  • ‘Gretel’
  • ‘Hansel’
  • ‘Ivory’
  • ‘Ophelia’
  • ‘Patio Baby’
  • ‘Pinstripe’

[/accordion-item]

[accordion-item autoclose=”true” clicktoclose=”true” title=”Okra” class=”Okra”]

  • ‘Carmine Splendor’
  • ‘Clemson Spineless’
  • ‘Jambalaya’

[/accordion-item]

[accordion-item autoclose=”true” clicktoclose=”true” title=”Pea” class=”Pea”]

  • ‘Caselode’
  • ‘Peas-in-a-Pot’
  • ‘Sugar Ann’

[/accordion-item]

[accordion-item autoclose=”true” clicktoclose=”true” title=”Pepper” class=”Pepper”]

  • ‘Cajun Belle’
  • ‘Cayennetta’
  • ‘Cherry Stuffer’
  • ‘Cute Stuff Red’
  • ‘Gypsy’
  • ‘Just Sweet’
  • ‘Lady Belle’
  • ‘Mariachi’
  • ‘New Ace’
  • ‘Orange Blaze’
  • ‘Red Chili’
  • ‘Sweet Golden Baby Belle’
  • ‘Tangerine Dream’

[/accordion-item]

[accordion-item autoclose=”true” clicktoclose=”true” title=”Radish” class=”Radish”]

  • ‘Champion’
  • ‘Comet’
  • ‘D’Avignon’
  • ‘Early Scarlet Globe’
  • ‘French Breakfast’
  • ‘Red Satin’
  • ‘Rido Red’
  • ‘Sparkler’
  • ‘White Icicle’

[/accordion-item]

[accordion-item autoclose=”true” clicktoclose=”true” title=”Squash” class=”Squash”]

  • ‘Astia’
  • ‘Golden Scallopini Bush’
  • ‘Golden Zebra’
  • ‘Multipik’
  • ‘Supersett’
  • ‘Sweet Zuke’
  • ‘Zebra Zuke’

[/accordion-item]

[accordion-item autoclose=”true” clicktoclose=”true” title=”Swiss Chard” class=”SwissChard”]

  • ‘Bright Lights’
  • ‘Fordhook Giant’
  • ‘Lucullus’
  • ‘Peppermint’

[/accordion-item]

[accordion-item autoclose=”true” clicktoclose=”true” title=”Tomato” class=”Tomato”]

  • ‘Amish Paste’
  • ‘Atlas’
  • ‘Baby Boomer’
  • ‘Bush Big Boy’
  • ‘Bush Champion’
  • ‘Bush Early Girl’
  • ‘BushSteak’
  • ‘Celebrity’
  • ‘Champion Bush’
  • ‘Cherries Jubilee’
  • ‘Cherry Cascade’
  • ‘Cherry Falls’
  • ‘Cherry Punch’
  • ‘Cocktail Red Racer’
  • ‘Container Superbush’
  • ‘Early Resilience’
  • ‘Fantastico’
  • ‘Husky Red’
  • ‘Jet Star’
  • ‘Lizzano’
  • ‘Maglia Rosa’
  • ‘Orange Pixie’
  • ‘Patio’
  • ‘Patio Choice Red’
  • ‘Patio Choice Yellow’
  • ‘Patio Paste’
  • ‘Patio Princess’
  • ‘Peardrops’
  • ‘Pony Express’
  • ‘Power Pops
  • ‘Primo Red’
  • ‘San Marzano’
  • ‘Sunrise Sauce’
  • ‘Super Bush’
  • ‘Sweet ‘n’ Neat’
  • ‘Sweetheart of the Patio’
  • ‘Tasmanian Chocolate’
  • ‘Terenzo’
  • ‘Tidy Treats’
  • ‘Tumbler’
  • ‘Tumbling Tom Red’
  • ‘Tumbling Tom Yellow’
  • ‘Veranda Red’

[/accordion-item]

[accordion-item autoclose=”true” clicktoclose=”true” title=”Close Accordian”]

[/accordion-item]

[/accordion]

In addition to the vegetables listed above, most varieties of herbs and salad greens are perfectly suitable for containers.

For more information on vegetable varieties for containers and container gardening in general:  See Extension Bulletin A3382, Container Gardening, or contact your county Extension agent.

Tomato Pruning

Tomatoes are a popular vegetable that many people grow in their home gardens.  Pruning tomatoes can create stronger and healthier plants that will grow larger numbers of higher quality tomato fruits later into the growing season.

Remove suckers from indeterminate tomato plants EXCEPT for the sucker below the lowest flower/fruit cluster.
Remove suckers from indeterminate tomato plants EXCEPT for the sucker below the lowest flower/fruit cluster.

Which tomatoes should I prune?  There are two broad categories of tomatoes:  determinate and indetermi­nate.  Determinate tomatoes grow to a certain size, then stop growing.  Indeterminate tomatoes continue to grow throughout the growing season.  Seed catalogues, seed packets or plant identifi­cation stakes will indicate which type of tomato you have.  Prune indeterminate tomatoes only.

Why should I prune my tomatoes?  Pruning indeterminate tomatoes improves fruit production by removing extra growth that diverts energy away from developing fruits.  Removing extra growth redirects energy back to the fruits and reduces fruit shading, both of which will help fruits mature more quickly.  Pruning also allows for more airflow within a plant, which reduces humidity and speeds the drying of any remaining leaves.  This drier environment is less favorable for fungal and bacterial disease development.  Removing the bottommost leaves of a tomato plant serves a similar purpose.

When should I prune my tomatoes?  Start pruning in late June or early July when the first tomato flowers are open and easy to identify.  Continue with a second and third pruning (as needed) every 10 to 14 days following the first pruning.  Stop pruning one to two weeks before your expected first harvest to allow time for tomato plants to produce canopies that will protect fruits from sunscald (pale, injured areas caused by exposure to direct sun).

How should I prune tomato plants?  Use the illustrations on this fact sheet as a guide.  Identify the main stem of the plant, and locate any suckers.  Suckers are branches that form in the leaf axils (the junctions between the true leaves and the main stem).  Next, identify the lowest flower/fruit cluster on the plant (i.e., the flower/fruit cluster closest to the ground).  Remove every sucker from the plant EXCEPT for the first one below the lowest flower/fruit cluster.  That sucker is the strongest one on the plant and should be left to grow and bear fruit as a second stem.

Remove suckers as indicated with your fingers, scissors or pruning tools.
Remove suckers as indicated with your fingers, scissors or pruning tools.

Suckers may be small, especially early in the season, but remove them as soon as possible.  Suckers left to grow will produce their own leaves, flowers, fruits, and even additional suckers, which will divert energy from tomato fruits produced on the primary and secondary stems.  Also, during the growing season, watch for and remove any root suckers that form at the bases of plants.

Remove suckers by pinching them close to the stem using your thumb and index finger (if the suckers are small), or using scissors or hand pruners.  Decontaminate your fingers by routinely washing your hands with soap and water or by using an alcohol-based hand sanitizer.  Decontaminate scissors/pruners (both prior to pruning and between each plant) by treating them for at least 30 seconds with rubbing alcohol.  Decontamination will help prevent the spread of disease-causing fungi, bacteria and viruses.

For more information on tomato pruning:  Contact your county Extension agent.

Poison Ivy

What is poison ivy?   Poison Ivy (Toxicodendron radicans), is a perennial woody plant that grows as either a low shrub or a climbing vine.  Poison ivy is native to North America and is common in Wisconsin, growing in pastures, roadside ditches, fence rows, wooded forests, beaches and parks.  CONTACT WITH POISON IVY CAN LEAD TO SKIN RASHES, SKIN BLISTERS OR OTHER ALLERGIC REACTIONS.

Young poison ivy leaves (left) can have smooth margins, while mature poison ivy leaves (right) often have serrated or lobed leaf margins.
Young poison ivy leaves (left) can have smooth margins, while mature poison ivy leaves (right) often have serrated or lobed leaf margins.

What does poison ivy look like?  Poison ivy has alternate leaves, and each leaf has three leaflets.  The middle leaflet has a short stalk and is larger than the two other leaflets.  Leaflets are variable in shape but are typically oval with pointed tips.  The margins (edges) of leaflets can be smooth, serrated (i.e., resemble a saw blade) or lobed.  In late summer, poison ivy produces clusters of whitish berries.  These berries are eaten by birds, and the seeds inside are spread through bird droppings.

Other common plants can be confused with poison ivy.  These plants and the characteristics that distinguish them from poison ivy are outlined in the table below.

Look Alike Species How to Distinguish from Poison Ivy
Boxelder (seedlings) Opposite branching; 3+ leaflets per leaf
Ash (seedlings) Opposite branching; 3+ leaflets per leaf
Virginia creeper 5 leaflets per leaf (newly emerged leaves may have fewer)
Wild sarsaparilla 3 leaves at the top of stem; each leaf with 3-7 leaflets
Raspberry/blackberry 3+ leaflets per leaf; spiny stems
Clematis/virgin’s bower Opposite branching; side leaflets with obvious stalks
Hog peanut Leaves without teeth or lobes; weak stemmed
Jack-in-the pulpit Leaves with 3 leaflets; leaflets all stalkless
Wild strawberry Leaves with 3 leaflets; leaflets all stalkless

Why is poison ivy a problem?  All parts of poison ivy plants (including leaves, stems and roots) produce a resinous oil called urushiol that can cause severe itching, inflammation and blistering.  The oil can be spread by anything that comes in contact with poison ivy including garden tools, clothing, boots or pets.  Urushiol is present not only in living poison ivy plants but can remain active in dead plants for up to two years.  Skin sensitivity to poison ivy can vary from person to person.  If you burn poison ivy, the vaporized oil that is released can cause severe systemic allergic reactions if inhaled.

How do I avoid or reduce problems associated with poison ivy?  LEARN HOW TO IDENTIFY POISON IVY AND AVOID CONTACT WITH THE PLANT WHENEVER POSSIBLE.  If you will be working in an area where poison ivy is likely to grow, wear long pants with boots, a long-sleeved shirt and gloves to help reduce exposure.  In addition, you may want to use a poison ivy preventative lotion that can provide additional protection.  After working in a poison ivy-infested area, carefully remove and wash your clothing with hot, soapy water.  Use sanitary wipes to clean gardening tools or other items that may have come in contact with poison ivy plants.

If you believe you have come in contact with poison ivy, immediately wash any potentially exposed skin with regular soap under cold, running water.  Avoid using complexion soaps as these types of soaps tend to spread urushiol on the skin and can make the problem worse.  Poison ivy cleansing products (e.g., Tecnu skin cleanser) can help remove urushiol from skin if used within four to eight hours of exposure.  Magnesium sulfate containing skin products (e.g., Dr. West’s Poison Ivy Wash) can also help to detoxify urushiol and ease itching.  If you believe you have inhaled urushiol vapor, IMMEDIATELY contact a physician for advice.

If you believe your pet has been exposed to poison ivy, immediately bathe them using a pet-safe shampoo to remove urushiol residues.

How can I control poison ivy?

Herbicides containing the active ingredients glyphosate and triclopyr are effective in controlling poison ivy if used according to the label directions.  Use foliar sprays to spot treat shrub-form poison ivy plants or vining poison ivy growing on inert objects (e.g., fences), but only apply treatments after leaves are fully expanded and plants are actively growing (i.e., summer and early fall).  DO NOT apply foliar sprays to poison ivy growing on trees and shrubs, as the herbicide may damage these supporting plants.  Alternatively, at any time of the year, cut poison ivy stems near the soil surface and paint the stumps with a more concentrated herbicide formulation.  Be sure to read the instructions on the label of whichever herbicide you select for details on how to use the product in the safest and most effective manner possible.

When removing poison ivy plants, collect all of the above ground plant parts.  Also, be sure to rake the ground to collect any leftover poison ivy berries, leaves, stems and roots.  DO NOT burn or compost any of these materials.  Instead, bag and dispose of them in your municipal garbage.  After you remove plants and debris, spread four to six inches of clean wood chip mulch over the site to prevent possible exposures to urushiol that may remain on or in the soil.

For more information on poison ivy:  Contact your county Extension agent.

Using Wood Ash in the Home Garden

Using wood ash in home gardens can increase soil fertility and raise soil pH.
Using wood ash in home gardens can increase soil fertility and raise soil pH.

Home gardeners often ask if wood ash can be used as a fertilizer in vegetable gardens and flowerbeds, around landscape trees and shrubs, and on lawns.  Wood ash can be a valuable source of certain nutrients and can also be used to modify soil pH.  However, it needs to come from an appropriate source and its use should be based on recommendations from soil fertility testing provided by a professional lab such as the UW Soil and Forage Lab (https://uwlab.soils.wisc.edu/).

What are the potential benefits of using wood ash?  Wood ash contains nutrients that can be beneficial for plant growth.  Calcium is the plant nutrient most commonly found in wood ash and may comprise 20% or more of its content.  Potassium (also called potash) is another common component of wood ash, occurring at concentrations of up to 5%.  Magnesium, phosphorus and sulfur are also typically found in wood ash at concentrations of up to 2%.  Finally, wood ash can contain trace amounts of iron, aluminum, manganese, zinc, boron and other nutrients needed by plants.

In addition to its nutrient content, wood ash can help in neutralizing soil acidity.  When wood is burned, high amounts of carbonates are produced.  Carbonates react with and neutralize acid in the soil, causing the soil pH to increase.  The levels of carbonates present in wood ash (and thus its acid-neutralizing properties) will vary depending on the type of wood burned and how the wood was burned.  In general, wood ash has about 50% less acid-neutralizing capacity than commercially available acid neutralizers such as pelletized lime or aglime.  Approximately four cups of wood ash can be substituted for one pound of aglime.

What are potential downsides of using wood ash?  On occasion, even the best wood ash may contain heavy metals such as cadmium and lead, but the levels of these metals can be minimized by carefully selecting the wood that is burned to produce the ash (see below for details).  In addition, the increase in soil pH associated with using wood ash tends to decrease the likelihood of plants taking up heavy metals.  If wood ash is used at recommended rates, concentrations of heavy metals should be low enough not to pose a threat to plants, or to animals or humans who eat plants grown in treated areas.  If you are concerned about heavy metals in your wood ash, consider testing for these elements prior to use.  The UW Soil and Forage Lab (mentioned above) does not test for heavy metals at this time; however staff can help answer questions about heavy metal contaminants.

Because using wood ash tends to increase soil pH, applying it where acid-loving plants (e.g., blueberries, azaleas/rhododendrons, birch trees, red maples, pin oaks) are growing will likely not be beneficial.  Using wood ash may actually be detrimental and contribute to problems with chlorosis [see University of Wisconsin Gardens Facts XHT1002 (Chlorosis), https://pddc.wisc.edu/, for details].  In addition, many vegetables and other landscape plants prefer slightly acidic soils, so wood ash should be used judiciously when growing these plants.  Finally, in some cases, increased pH due to use of wood ash may promote certain diseases.  As an example, potatoes grown at higher pH tend to be more prone to potato scab [see University of Wisconsin Gardens Facts XHT1117 (Potato Scab), available at https://pddc.wisc.edu/, for details].

In order to use wood ash in the best manner possible, always make applications to garden soils based on the plants that are to be grown and based on recommendations from a certified soil testing lab.

What type of wood ash should I use?  If you decide that using wood ash is appropriate for your gardening needs, only use wood ash that has come from trees grown in natural areas.  DO NOT use wood ash produced from trees grown near industrial sites, in soils that may be contaminated with toxins or heavy metals, or if you have no knowledge of the origin of the wood that you are burning.  Also, DO NOT use ash produced by burning treated wood, waste oil, plastics or garbage.

How do I apply wood ash?  Prior to use, sift wood ash to remove large charcoal pieces, as well as any active embers.  Apply only the amount of wood ash recommended based on a soil fertility test and based on the nutrient needs of the plants that you intend to grow in the treated area.  Applying excessive amounts can lead to nutrient toxicity and/or nutrient deficiency issues in plants.  Applications of wood ash are generally limited to a maximum of 15 to 20 pounds (approximately a five gallon pail) per 1000 sq. ft., per year.  Spread wood ash evenly over the area to be treated (e.g., vegetable garden bed, established perennial flowerbed, lawn or other landscape area) during the winter.  Because wood ash particles are very fine and can easily be blown by the wind, avoid making applications when it is windy.  Whenever possible, apply wood ash to moist soil.  Where feasible (e.g., in a vegetable garden), work the ash into the soil using a rototiller, spade or rake in early spring.

Due to its alkalinity, wood ash can potentially pose a human health risk.  Therefore, when working with it, be sure to wear appropriate protective clothing (e.g., long pants, long sleeve shirt, gloves, eye goggles, dust mask) to limit exposures that might lead to skin, eye or respiratory irritation.

For more information on using wood ash in the home garden, as well as soil fertility testing:  Contact your county Extension agent.

Bagging Apples for Insect and Disease Control

Producing high quality apples in home gardens can be challenging due to damage caused by insects (e.g., apple maggot, codling moth, plum curculio, stinkbugs) and fungal diseases (e.g., apple scab, cedar-apple rust, flyspeck, sooty blotch).  Many insects damage apples when they lay their eggs in developing fruit.  Insect larvae can cause

Bagging apples can reduce fruit damage due to insects and diseases. (Photo courtesy of Janet van Zoeren)
Bagging apples can reduce fruit damage due to insects and diseases. (Photo courtesy of Janet van Zoeren)

additional damage as they tunnel into the fruit.  Wind-borne fungal spores can land on fruit leading to infections that damage fruit, reduce fruit aesthetics or affect long-term storage.

Although insecticide and fungicide sprays can help control insect pests and diseases, regular spraying can be inconvenient and costly for homeowners.  A non-pesticide alternative for protecting fruit is to encase apples in bags that provide protective barriers against insects and fungal pathogens.

What do I need to bag my apples?  First, you will need some sort of bagging material.  This could be a household plastic or paper bag, or a commercially-produced bag designed specifically for apple bagging.  Perhaps the most convenient choice is a common plastic sandwich or quart-size zip-type bag.  Zip-type bags are effective, weather proof, economical, and readily available.  You will also need something (e.g., a twist tie, tape, string, staples) to secure the bags to your apples and a pair of scissors to cut a drainage hole in each bag.

When do I bag my apples?  Start bagging when fruits are approximately ½ to 3/4 inch in diameter.  Apples typically reach this size approximately two weeks after petal fall.  Thin each cluster of apples to a single fruit, keeping the largest, best-shaped fruit in the cluster.  Make sure that the apples you select have not already been damaged.  In particular, plum curculio can damage fruit and codling moth can lay eggs before fruit are large enough to bag.  You may want to consider using an insecticide spray between petal fall and bagging to prevent this early damage.

How do I bag my apples?  Place an apple in the bag of your choice with the top of the bag around the stem.  Carefully secure the bag with a twist tie, tape, string or staple without damaging the stem.  If using a zip-type bag, place the stem in the middle and close the seal to within one inch of the stem on each side.  Staple the bag on each side of the stem to ensure that the bag will remain secure all summer.

Use scissors to cut approximately one-half inch from one of the bottom corners of the bag. This will allow condensation that may form inside the bag to drain.

Leave plastic bags on all summer.  Paper bags may deteriorate and need replacement if there is excessive rain during the growing season.  In addition, paper bags should be removed a few weeks prior to harvest to allow proper fruit color to develop.

Bagging apples can help prevent damage due to insect pests such as codling moth (left) and diseases such as apple scab (right). (Photos courtesy of Christelle Guédot and the UW-Plant Disease Diagnostics Clinic).
Bagging apples can help prevent damage due to insect pests such as codling moth (left) and diseases such as apple scab (right). (Photos courtesy of Christelle Guédot and the UW-Plant Disease Diagnostics Clinic).

What should my apples look like after they have been bagged?  Because bags prevent insects and fungal spores from reaching fruit, most of your bagged apples should be in near perfect condition.  Fruit that you do not bag will likely be blemished from insects and disease.  Blemished fruits should be removed (whether they fall to the ground or remain attached to your tree) and destroyed by burning (where allowed), deep burying or hot composting.  Diseased leaves from your apple tree should be treated similarly once they fall from the tree in the autumn.  Properly disposing of blemished fruits and diseased leaves will help limit overwintering of insect pests and disease-causing organisms, thus reducing insect and disease problems the following growing season.

For more information on bagging apples for insect and disease control:  Contact your county Extension agent.

Improving Cranberry Pollination

Successful cranberry production relies on cranberry flowers being adequately pollinated.  This fact sheet discusses several strategies that can be used to optimize pollination.

Proper pollination is important for successful cranberry production. (Photo courtesy of Johnston's Cranberry Marsh & Muskoka Lakes Winery, Ontario, Canada).
Proper pollination is important for successful cranberry production. (Photo courtesy of Johnston’s Cranberry Marsh & Muskoka Lakes Winery, Ontario, Canada).

Increase and diversify plants attractive to pollinators.  Having both native pollinators and honeybees on your marsh serves as an “insurance policy” to promote good fruit set.  Providing diverse sources of nectar and pollen (e.g., through the use of a pollinator garden), will encourage native pollinators to establish themselves long-term near your marsh and improve the health of honeybee colonies.  When planning a pollinator garden, select a site that is sunny and 1/3 to one mile away from your marsh.  Some common native plants to consider for a pollinator garden are listed in the figure below, with their approximate bloom times.

Promote nesting habitats for wild bees.  Wild bees need places to build their nests.  Approximately 70% of native bees nest underground and need areas of bare, sandy or loamy soil to build their nests.  The remaining 30% build nests by tunneling into stumps or twigs, or by constructing nests in cavities (e.g., in mounds of tall grasses, in debris piles, or in deserted rodent nests).  Native pollinators typically travel from 1/8 to one mile from their nests to feed, so suitable nesting areas need to be within this distance of a marsh for the bees to contribute to cranberry pollination.

Several programs can assist with the costs of creating pollinator habitats.  These include the USDA Environmental Quality Incentives Program, the USDA Farm Service Agency, the Wisconsin DNR Land Owner Incentive Program and the Bayer Crop Science Feed a Bee Initiative.

 

LEFT: Approximate bloom times for plants that are recommended to be grown near cranberry marshes as a supplemental nectar and pollen source for cranberry pollinators. RIGHT: Approximate flight periods for major groups of bees (including native species) found in cranberry marshes. The pink columns in both graphs represent the approximate time of cranberry bloom.
LEFT: Approximate bloom times for plants that are recommended to be grown near cranberry marshes as a supplemental nectar and pollen source for cranberry pollinators. RIGHT: Approximate flight periods for major groups of bees (including native species) found in cranberry marshes. The pink columns in both graphs represent the approximate time of cranberry bloom.

Reduce pesticide exposureYou can optimize bee health by creating a pollinator protection plan that promotes:

  • Practicing integrated pest management (IPM). IPM, which involves monitoring for pests and using a variety of appropriate management strategies, is used by most Wisconsin cranberry growers.
  • Spraying when bees are least active. Most bees forage from early morning until shortly before sunset. Therefore, the best time to apply a pesticide, especially during bloom (if allowed by the pesticide label), is in the late evening or at night.
  • Limiting pesticide drift. Whether plants are blooming or not, using a boom sprayer allows for direct application of pesticides onto cranberry plants.  Other methods that can reduce pesticide drift include calibrating your boom to optimize spray pressure and volume, selecting drift-reducing nozzles, avoiding pesticides with small particles that easily drift, and spraying when winds are under 10 mph and when relative humidity is above 50%.
  • Using insecticides and fungicides that have a reduced risk for bees. See the table below for insecticides and fungicides that are least toxic for bees.
Class
(IRAC or FRAC code)
Example
Active Ingredient(s)
Example
Trade Names
Insecticides

(IRAC code)*

diamide (28) chlorantraniliprole Altacor
diacylhydrazine (18) methoxyfenozide

tebufenozide

Intrepid

Confirm

biological Bacillus thuringiensis Biobit, Dipel
Fungicides

(FRAC code)*

strobilurin (11) azoxystrobin Abound, Evito
chitin synthase inhibitor (19) polyoxin D zinc salt Oso
biological Reynoutria sachalinensis Regalia

*  Note that rotating Insecticide Resistance Action Committee (IRAC) classes and Fungicide Resistance Action Committee (FRAC) codes (modes of action) will help delay development of pesticide resistance.

Strengthen your working relationship with beekeepers.  Optimal cranberry pollination requires cooperation between grower and beekeeper.  In some cases, outlining expectations in a signed, written contract can be the best way to prevent misunderstandings.  Topics to consider and discuss with your beekeeper can include, but are not limited to:

  • Hive inspections. Inspecting a random sample of 10% of hives when they are brought onto a march can help ensure that hives are of high quality and contain healthy bees.  Ideally, a third party should conduct the inspections in the presence of both beekeeper and grower.
  • When bees are introduced onto a cranberry marsh and the duration of their stay are important factors in optimizing cranberry pollination, as well as for maintaining honeybee health.  Bees should be brought onto a marsh at around 15% bloom.
  • Hive placement. Within the limits of your bed layout and equipment needs, it is best to place hives in the center of a marsh or near marsh edges with wild habitat, but away from water reservoirs, as bees from hive near water seem to be less likely to visit cranberry plants.
  • Exposures to sprays. Be explicit about when, how and what may be sprayed during bloom.

For more information on improving cranberry pollination:  Watch for UW Extension bulletin A4155, “Practices to improve pollination and protect pollinators in Wisconsin cranberry” (available soon at https://learningstore.uwex.edu/), or University of Wisconsin Garden Facts XHT1213 “Pollinators” (available at https://pddc.wisc.edu/), or contact your county Extension agent.

How to Properly Prune Deciduous Trees

Why should I prune my trees? Pruning is important for a variety of reasons. Pruning can help control the size of a tree, direct growth, influence flowering or fruiting, or maintain plant health and appearance. Pruning can also increase the safety of a tree by removing broken, diseased, dead, or dying branches. In addition to pruning, selecting plants that are suited to your environment and location are very important. The ultimate height and spread, in addition to location of overhead power lines, should be taken into account when selecting trees for landscaping.

The three step method of pruning large limbs.
The three step method of pruning large limbs.

What should I prune?

  • Newly planted trees: Newly planted trees should not be pruned unless a branch is broken, diseased or dead. These trees need foliage to produce carbohydrates (sugars) that are then transported to the root system for initiation of new roots.
  • Young trees: After a young tree is established for two to five years, the tree can be pruned to encourage a well-branched canopy. Lower branches can be removed to raise the canopy, if desired. Scaffold branches to be maintained in the tree should be selected such that they are 12-18 inches apart, are evenly distributed around the trunk and have wide crotch angles. Remove no more than 13 of the total crown of a tree at one time. Young trees also need corrective pruning to remove crossing branches, double leaders, watersprouts, and root suckers.
  • Older trees: Older, established trees, if properly trained when young, require little pruning. These trees should never be topped as this leads to poor branch structure and increased limb breakage. Use the three-point method of limb removal for pruning large branches (see diagram above and description below). This method ensures proper pruning and closure of wounds. Contact a certified arborist to prune larger limbs and remove trees, particularly if the tree is close to power lines or buildings.

The 3-point method of proper pruning of large limbs

When doing any type of pruning, always use a sharp pruning saw for making pruning cuts. Also, be sure to disinfect your pruning tools with alcohol or a 10% bleach solution after each pruning cut to avoid spreading diseases.

  • Step one: Select the branch that you want to remove. On large limbs, the first cut should be 12 to 18 inches from the limb’s point of attachment. The pruning cut should be an undercut made 12 way through the branch (see diagram). This pruning cut is very important because it relieves weight from the branch collar and prevents accidental tearing of bark from the tree’s trunk when the limb is removed.
  • Step two: The second pruning cut should be made on the outside of the first cut (i.e., farther from the trunk). Cut all the way through the limb from the top down, thus removing the weight of the branch.
  • Step three: The final cut should be made next to the tree’s trunk outside of the branch collar. Cut from the top down and cut all the way through the remaining branch stub. The branch collar should be left intact. DO NOT cut the branch flush with the tree’s trunk. A proper cut avoids large wounds, and allows the tree’s wound to close quickly.

Should I use wound treatments? In general, wound treatments, such as tree paint or wound dressing, are not recommended. These compounds slow down wound closure and promote decay. One exception when wound treatments are recommended, is the case of oak trees that are pruned during the growing season. Using wound treatments on oaks is important to keep out insects that transmit the oak wilt fungus (see University of Wisconsin Garden Facts X1075).

When should I prune trees? Most deciduous trees should be pruned in late fall to winter. At this time of year, you can see the overall branch structure easily, and most insects and disease causing organisms are not active. Late fall/winter pruning is especially important for oak trees to help prevent spread of the fungus that causes oak wilt (see University of Wisconsin Garden Facts X1075). Late spring and summer are usually not good times of year to prune because disease pathogens are present and wound closure is slower. If you prune in late winter, some trees may bleed or ooze sap excessively in the early spring. The bleeding may be unsightly, but does not harm the tree. Examples of trees that bleed excessively are maple, willow, birch, walnut, beech, hornbeam, elm, and yellowwood.

Definitions:

  • Branch collar: the ring of trunk tissue that surrounds a lateral branch at the point of attachment to the stem.
  • Double leaders: two major, terminal growing points located at the top of the tree.
  • Root suckers: vigorous, upright, adventitious shoots that arise from latent buds below the graft union or at the base of the tree.
  • Scaffold branches: the large branches that form the main structure of the crown of a tree.
  • Topping: an improper pruning technique that reduces the height of a tree by removal of large branches back to larger primary branches. This technique is not recommended.
  • Watersprouts: vigorous, vertical, adventitious shoots that arise from latent buds above the ground or graft union on older wood.

For more information on pruning: See UW-Extension bulletins A1817, A1771, A1730 and University of Wisconsin Garden Facts XHT1013, XHT1015, or contact your county Extension agent.