UW-Extension Walworth County

05/28/2026

🌱 This Week in the Garden: Your Questions Answered, Week of May 25

The birds are singing, the sun is shining, and we are back to the glorious spring weather Wisconsin has to offer. What’s been happening in your yard and gardens lately?

❓ Question:
Small caterpillars or worms have completely devoured all of the leaves on one of my bushes (see photo below). What can I do to stop them and should the bush be removed?

🌿 Answer:
Those are the larvae of viburnum leaf beetles (VLB for short). VLB larvae typically appear in early to mid May and can cause significant damage to viburnum shrubs. Then the larvae will move down into the soil to pupate before they emerge as adults in late June - early July. Any treatment methods are targeted towards the larvae and adults.
If your viburnum was a healthy plant, it’s possible that it could recover and isn't totally dead yet. However, if it's been suffering through multiple years of VLB infestation and/or other stressors, then it could be declining and it might be best to replace it.

What are your options?
Keep the shrub, see if it recovers, and treat VLB eggs and larvae as indicated by our fact sheet linked below. If you do keep the shrub, I wouldn't recommend digging up the soil (to try to find the pupae) around it as that can cause more stress or harm to the plant.
Replace the shrub with another viburnum but check out our fact sheet for varieties that are less susceptible to VLB damage.
Replace the shrub with something totally different.

🔗 Learn more:
https://hort.extension.wisc.edu/articles/viburnum-leaf-beetle/

❓ Question:
What else can I do to support pollinators in my yard?

🌿 Answer:
Pollinators need three core habitat features: Food, Shelter, and Protection - especially from chemical insecticides. A healthy pollinator habitat provides a mix of flowering plant species that bloom at different times throughout the growing season. Therefore, planting native species that support insect pollinators is always a good thing to do! They also need safe places to nest, overwinter and find refuge. This can include stems and branches, leaf litter, bare ground, dead wood, brush piles, and rock piles. Did you know that most of our native bees are solitary bees (meaning they live alone) and 70% of them nest underground? And they need protection from habitat disturbances and chemical pesticides (especially insecticides) which can be directly and indirectly harmful to our insect pollinators. A new study suggests that reduced chemical use is MORE important for conservation efforts than just planting more flowers. Read more about this study in the link below.

Join Julie Hill, your local Horticulture Educator, to learn more about how you can support pollinators in your yard at “Planting for a Buzz: A Guide to Pollinator Friendly Gardening” on Wednesday, June 3rd at 1PM at Barrett Memorial Library in Williams Bay.

🔗 Learn more:
https://grow.cals.wisc.edu/priority-themes/food-systems-priority-theme/what-a-wild-bee-wants

https://www.williamsbay.lib.wi.us/site/events/

💬 Have a question of your own?
Reach out—we may feature it in an upcoming post!
You can reach Julie, your local horticulture educator by calling 262-741-4958, Text 262-374-4191, email [email protected] or use our online form: go.wisc.edu/PlantQ

📷Viburnum leaf beetle larvae

05/18/2026

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05/14/2026

🌱 This Week in the Garden: Your Questions Answered, Week of May 11

With the promise of warmer weather in our near future (and hopefully no more frost warnings), let’s get outside and dig in! Lots of information to share this week....

❓ Question:
I’m having a problem with perennial w**ds in my yard. No matter how many times I pull or cut them, they keep coming back!

🌿 Answer:
Ugh! Thistle, creeping bellflower and other perennial w**ds can be really challenging to get a handle on because of their underground structures that can store a large amount of energy. They can also reproduce from those perennial parts and seed. They can have extensive root systems that are hard to pull or dig all the way out. But you can get things under control with some persistence and an integrated approach of removal, thick layers of mulch, and where appropriate, careful and targeted herbicide use. See the video below for more recommendations!

NOTE: Herbicides (chemical plant killers) are not the “go to” option. They should only be used for judicious spot treatments and in ways that minimize risk to pollinators and other negative environmental impacts. You are legally required to follow the product label. Please contact us with questions.

🔗 Learn more:
https://youtu.be/pZqJDpbTDqY?si=22tuLBEY-RCMNmK6
https://renzw**dscience.cals.wisc.edu/

❓ Question:
I’m noticing that my tree’s roots are growing at the surface of my lawn. What should I do?

🌿 Answer:
Some tree species are more prone to doing this, but it can happen with almost any tree. It’s important to remember that the majority of the tree roots are within the top 8” of soil. As the tree grows, roots can be more visible at the surface as they get bigger, or if there is erosion of the surface soil, or if the soil is compacted and doesn’t drain well.

Do NOT prune these roots as that can cause serious damage to your tree. Instead, you can apply a shallow, 1 – 2 inch layer of good-quality soil mix and then replant the grass. However, it won’t be long before tree roots will reappear again. Even better, replant the affected surface area with a taller ground-cover type plant and other flowering plants that will not need mowing, being careful to avoid injury to the major tree roots at planting.

🔗 Learn more:
https://www.purdue.edu/hla/sites/yardandgarden/when-tree-roots-surface/

💬 Have a question of your own?
Reach out—we may feature it in an upcoming post!
You can reach Julie, your local horticulture educator by calling 262-741-4958, Text 262-374-4191, email [email protected] or use our online form: go.wisc.edu/PlantQ

Ask a Gardening Question Sponsored by the UW-Madison Division of Extension Horticulture Program Looking for expert advice on a lawn, landscape or gardening issue? Fill out the form below and attach photos showing your garden concern. A Wisconsin Extension Master Gardener or Extension staff will resp...

05/13/2026

Upcoming Program! Registration Required.

Gardening for Hummingbirds
Monday, May 18, 6:00 p.m.
Milton Public Library-Wisconsin

Join us to unravel the secrets of attracting the “jewels of the garden.” From territorial displays to fierce competition, we will dive into the hummingbird’s world to learn how your garden or yard can meet their needs. We will explore the challenges facing hummingbirds in our region and learn how to make your yard hummingbird friendly with flowers, perches, insects, and water. We will also get hands-on by creating a hummingbird perch for your yard.

For Adults.

Registration required: https://www.als.lib.wi.us/MPL/ #/events/JNN2CPbSDj/instances/DM5PfTiHrU/

04/30/2026

🌱 This Week in the Garden: Your Questions Answered, Week of April 27

❗❗❗Frost Advisory - Thursday, April 30 and Friday, May 1!
Cover your cold-sensitive plants TONIGHT! And probably tomorrow night too.

❓ Question:
When should I spray my apple trees for pests?

🌿 Answer:
For any fruit crop, it’s important to utilize an integrated pest management plan to help minimize damage from pests (like disease or insects) and maximize fruit production. In order to do this, it’s also important to know which diseases or insects you are trying to prevent or manage. Identification is a critical first step, then determining how bad the problem is, then figuring out which methods work for you and for your fruit crops. By understanding which pests you are trying to manage, you will be better equipped to apply products at the right time of year, based on the life cycle of the pest.
Our apple trees are in full bloom right now so we want to wait until petal fall to do any spraying. Diseases like scab and fire blight and possibly some early season insects like aphids and scale are the pests that are being addressed early in the season.

🔗 Learn more:
Check out these free online programs about apple insect pests: https://hort.extension.wisc.edu/free-online-programs/

https://fruit.webhosting.cals.wisc.edu/wp-content/uploads/sites/36/2011/06/Apple-Pest-Management-for-Home-Gardeners.pdf

https://yardandgarden.extension.iastate.edu/how-to/spray-schedule-home-apple-trees

https://hort.extension.wisc.edu/articles/home-fruit-insecticides/

❓ Question:
I’m noticing a lot of w**ds in my lawn, what do I spray on them to kill them?

🌿 Answer:
Well….do you absolutely need to spray and kill them? A lawn that is maintained well through best practices like planting and maintenance like mowing and proper fertilization, will outcompete w**ds. A “w**d” just means that it’s a plant that you don’t want growing in that spot. Depending on your own goals for your lawn, plus the amount of money, time and overall effort you want to put into your lawn, maybe a few w**ds are okay. If you are looking for a w**d free lawn, then using an integrated pest management approach will give you the best success. Chemicals should always be a last resort and if you decide to treat specific w**ds with an herbicide (chemical plant killer), then make sure you are following the product label and using it in the most effective but least harmful way.

🔗 Learn more:
https://hort.extension.wisc.edu/articles/wisconsin-lawn-care-calender/
https://hort.extension.wisc.edu/articles/lawn-maintenance/

💬 Have a question of your own?
Reach out—we may feature it in an upcoming post!
You can reach Julie, your local horticulture educator at 262-741-4958 or [email protected] or use our online form: go.wisc.edu/PlantQ

📷Apple flowers

04/29/2026

🌱 This Week in the Garden BONUS

✨BONUS
Last week we shared a picture of something unknown on a clematis branch. If you didn’t see it yet, check out the photo in this post.

Did you look? What do you think?

Those are katydid eggs. Katydids are more closely related to crickets than to any type of grasshopper. You may find some feeding on leaves and flowers in your garden or on your potted plants, especially in late summer, but they won’t cause your plants significant damage. In our area katydids overwinter as eggs. Females deposit eggs in soil, plant stems (like this clematis branch!) or tree bark in late summer or fall. The adults die off, and the following spring the eggs hatch.

🔗 Learn more:
https://hort.extension.wisc.edu/articles/katydids/

04/23/2026

🌱 This Week in the Garden: Your Questions Answered, Week of April 20

✨BONUS
Look at the picture - What are these on this clematis branch?

🌿 Answer:
Put your guesses in the comments and the answer will be revealed next week!

❓ Question:
I’ve heard I shouldn’t prune my oak trees this time of year - why?

🌿 Answer:
Try to avoid pruning any oaks from now until at least July 15. The reason is that we are currently in a HIGH RISK period for OAK WILT, from April 15 to July 15. Oak wilt is a deadly disease that affects oak trees. Oak wilt is caused by a fungus which survives in infected living oaks and in oaks recently killed by the disease. The fungus can also survive in firewood harvested from an infected tree.
Sap beetles are attracted to mats of the oak wilt fungus in infected trees, pick up spores of the fungus on their bodies, then carry spores to healthy trees. These beetles are attracted to trees that have been recently wounded by wind or storm damage, or by pruning. And these beetles can find these wounded trees within minutes of the injury.

Pruning most woody trees and shrubs should be done during the winter when diseases and pests are less active. But understandably, you might have to deal with storm damage or unexpected pruning. While we don’t typically recommend applying any sort of pruning paint, IF you are pruning during this time of year, then you should immediately apply a pruning paint over the wound.

🔗 Learn more:
https://hort.extension.wisc.edu/articles/oak-wilt/

❓ Question:
I’m getting my vegetable garden ready, can I add manure?

🌿 Answer:
Manure can be used as a soil amendment in the home garden, which helps improve soil structure and drainage, adds organic matter, and provides some nutrients. However, do not apply fresh manure in the spring. When applying fresh manure where you are growing edible crops, application should be made about 4 months in advance, meaning fall is a great time to apply fresh manure.

Composted or aged manure can be spread now. It is best to wait a least one month before planting crops so the microbial activity it stimulates won’t interfere with seed germination. Composted manure is defined as manure that has undergone the composting process, in which microorganisms decompose biodegradable organic matter under aerobic conditions (in the presence of oxygen).

🔗 Learn more:
https://hort.extension.wisc.edu/articles/using-manure-in-the-home-garden/

💬 Have a question of your own?
Reach out—we may feature it in an upcoming post!
You can reach Julie, your local horticulture educator at 262-741-4958 or [email protected] or use our online form: go.wisc.edu/PlantQ

04/20/2026

04/20/2026

They're back........ not with a scary voice, use an excited voice to say that because the jewels of the garden are back!

Our Ruby Throated Hummingbirds are arriving from a massive migration and need to refuel as well as prepare for rearing their young. They have BIG appetites! They need to visit 1500 flowers and eat 600+ insects - EVERY. SINGLE. DAY.

How can you help?

🌺 Plant more flowers!
Hummingbirds need both nectar and insects. A diversity of plants in our yards and neighborhoods can help feed hummingbirds all year long.

🥤Add feeders.
Hummingbirds are very territorial, so the more feeders the better. Use a sugar water solution of 4 parts water, 1 part white sugar, boil for 2 minutes, then cool. You can refrigerate it for a few days if you make a big batch. Do not microwave and do not use any red dyes, honey, or artificial sweeteners.

🐜 Reduce or eliminate pesticides, especially insecticides.
All birds rely on insects for food (as well as other animals), yet insect populations are in massive decline. Before you reach for chemical treatment for a pest in your yard, learn about all your options and use an integrated approach that doesn't rely on chemicals.

Map of 2026 hummingbird migration and sightings in the United States and Canada from the Hummingbird Central migration tracker

04/15/2026