From the Gardens Registrar: It’s Thistle Time at Eagle Heights!;  Leaf Mulch at UH; Mowing and Paths; Jumping Worms; Potato Beetles

Hello Gardeners,

THISTLES – Thistles are a large group of plants in the Aster family, characterized by leaves with spines or prickles on them. The family includes artichokes, and some garden ornamentals, as well as some native plants. Also, many small birds, such as goldfinches, enjoy eating thistle seeds. But most of the thistles found in our gardens and in the Lakeshore Preserve are invasive and obnoxious. The worst of them is the Canada Thistle (Cirsium arvense.) This plant is classified as “restricted” by the Wisconsin Department of Natural Resources, because it causes significant environmental harm, by invading natural areas, spreading, and crowding out other vegetation. Here’s a link to their website on this topic: https://dnr.wi.gov/topic/Invasives/fact/CanadaThistle.html  The website includes pictures. The thistles are getting big now, and starting to get flower buds. If you have this plant in your plot, dig it out immediately. It spreads most through its roots, but it can also spread by seed, so don’t let it flower and go to seed. If you can’t dig it out, at least cut it down to keep it from flowering. You do not want this plant in your own garden, and you don’t want it spreading from your plot to anyone else’s.

LEAF MULCH AT UNIVERSITY HOUSES – The University Houses Gardens finally have leaf mulch from the Village of Shorewood, thanks to the persistence of your fellow gardener, Gemma. Thank you very much, Gemma. Also, bark mulch will be coming soon. We’re cutting down dead apple trees at Eagle Heights, and they will be taken to UH to be chipped.

MOWING/PATHS  – The paths are looking better now, thanks to work by our garden worker, the Housing workers, and some volunteers. If you have a weed whacker at home, you’re welcome to use it at the gardens to knock down tall grass and weeds that still border a few of the paths. (Let me know if you’re doing this, and I’ll give you workday credit.) On a related topic, one of the University Houses gardeners asked me to remind their fellow gardeners to keep their side paths cleared, so that the gardeners in plots farther from the main path can get around.

JUMPING WORMS – All earthworms in North America are actually invaders – there are no native earthworms here. But most worms are welcome garden residents, because they aerate and fertilize the soil. But Jumping Worms are harmful to soil, and spread rapidly. There isn’t yet a way to control them. We have had them in our gardens for a number of years, and gardeners have wondered if they lived in our leaf mulch. We always felt that the pile got hot enough that nothing could live in it. But this year, I have been seeing earthworms in the leaf pile. I haven’t seen jumping worms (yet), but I suggest that gardeners take leaves from higher up in the pile, and avoid leaves on the ground, which is where I’ve seen worms. Here’s the DNR information on jumping worms: https://dnr.wi.gov/topic/invasives/fact/jumpingworm/index.html

POTATO BEETLES – More bad news. Many gardeners are reporting potato beetles on their potato plants. They attack other plants as well, including potato relatives such as tomatoes. The surest way to get rid of these beetles is, unfortunately, picking them off your plants, one by one, and tossing them into soapy water. But you can also try neem oil – this is an organic pesticide. Some years, the garden workers spray Spinosad, which is an organic treatment for the beetles. But Spinosad can be harmful to bees, so spraying has to be done very carefully, and some gardeners don’t want it used on their plots. (When we spray, it’s done in the evening after the flowers are closed and the bees aren’t around. Also, it can’t be done safely when it’s windy or raining.) Let me know if you’d like us to spray.

Happy Gardening, and Stay Safe,  

Kathryn