Playing in the dirt with Mary D.: From creeping Charlie to squash bugs ...

By MARY DICKINSON
UI Extension Master Gardener


Wow! What a great response from the Paxton Record’s online readers. Thank you for three excellent garden questions. Creeping Charlie, squash bugs and “What’s wrong with my tree?” are the topics I’ll discuss this time.

Readers can send their questions to: Will Brumleve at the Paxton Record at will@paxtonrecord.net. Put “Garden Question” in the subject box. You can also mail them directly to me at P.O. Box 325, Loda, IL 60948.

Prevention is the best way to keep pests from harming your gardens. Get rid of weeds; remove any diseased or dead foliage that can harbor insects; rake and shred leaves and turn them into mulch or compost. When the ground freezes add about 2-4 inches of mulch, especially around plants that are marginally hardy in zone 5. Mow your lawn one last time around Thanksgiving and apply a winterizing fertilizer.

Is there any way of getting rid of creeping Charlie?

Creeping Charlie (glechoma hederacea) is the bane of many gardeners’ existence. Imported to this country by European settlers, it was used in traditional medicine as a treatment for a variety of ailments and as a salad green. A variegated form was once sold as a container plant. Unfortunately, it escaped its pot and soon overtook our lawns and gardens showing its ability to thrive in sunshine and in shadow and is now known as an invasive weed. There are several ways to get it out of your gardens – all of which require great perseverance because it spreads by stolons (stems that grow at or below the ground level).

You can dig it out, but probably by now, you have tried this and it hasn’t worked very well. That’s because digging invariably breaks the stems and roots of this weed. When that happens, you have essentially root pruned it and encouraged its re-growth in a different direction. If you dig it out be very persistent! Do not let any little bit of root remain in or on the surface of the soil or it will sprout anew. However, hand removal is still the best way to get creeping Charlie out of flower and vegetable beds. When you’ve removed as much as possible, cover with about 3 inches of mulch.

This doesn’t work so well if Charlie has taken over your lawn. In this case you will want to mow high-about 3-3 1/2 inches and apply a post-emergence herbicide. Chemical applications of broadleaf weed killers are effective if applied while the plant is growing and in a fall -spring -fall application cycle. There are products labeled for use in lawns and around ornamentals. Look for products containing dicamba, 2, 4-D and mecoprop. It takes persistence to kill creeping Charlie so be prepared to make several applications always following label directions. It’s not too late to start applying this in November. If your infestation is so severe that these measures don’t work, you can kill the whole area with glyphosate and reseed in the spring.

To make a new bed that is relatively weed free, cover the area with black plastic , several layers of newspapers, or cardboard  and mulch. Wait several weeks depending on the temperatures before planting. When it looks like the weeds are gone, plant your bed with plants that compete well with weeds. Vinca, hosta, and pachysandra are good choices for shady areas where Charlie thrives. 

For more information go to http://hyg.ipm.illinois.edu/pastpest/200114e.html.

My zucchini had stinkbugs (or something similar) this year, and Sevin didn’t seem to bother them a lot-any suggestions?

Were the bugs you saw a kind if grayish color, shield shaped and about ½ inch wide and ¾ inch long?

If yes, then they were probably squash bugs and are a pain to control. They injure the leaves and stems sucking the life right out of the plants! Squash bugs lay bright brown eggs on the leaves usually in tidy little rows, and although there is only one generation of them, they can be found in all stages of growth all summer long. That means you have to keep scouting for them and doing whatever it takes to remove them.

Eggs can be picked or rubbed off the leaves and squished. When the nymphs (baby bugs) hatch they look like small versions of the adults.  Nymphs and adults can be handpicked and dropped into a container of water or squished–if you are squeamish wear gloves or pay a child to do this for you. You can wash them off the plants with a strong spray of water – but they’ll probably just come back somewhere else on the plant.

Preventing the pests is usually the best cure. This fall, clean up any plant debris left in the garden. Do not compost any parts of the affected plants.  In the spring, plant your squash in a different area of the garden and cover the young squash plants with floating row cover to keep other squash munchers from attacking the young plants. Tuck the row cover under the leaves of the plants and secure it with ground staples or something heavy to keep it from blowing away.  Keep this on until the blossoms start to show. The row cover needs to come off to let the pollinators in, so remove it and keep scouting for insect pests. Lay down boards and check for bugs during the day when they hide under them. Remember to weed and mulch and keep the plants as healthy as possible so they can resist bug attacks.

If all else fails and you need to use a pesticide, use one containing cyfluthrin or permethrin. The active ingredient in Sevin is carbaryl which will work on the vine borers but not as well on the squash bugs. To avoid killing pollinators, spray late in the day. Remember to read and follow all label directions.

I have a question about my rose of Sharon trees. I planted four of them about 15 years ago, just four little twigs. Three of them are now about 12 to 15 feet and produce beautiful flowers mid July. One of them only reached about 6 feet tall and each year gets a little worse. The leave start to sprout but don’t get out of the sprout stage, the leaves are small and wrinkly. I hate to cut it down because it tries so hard to live but now one of its neighbors is now showing the same signs in part of the tree. So I am going to cut them both down this spring so it doesn’t spread any further, do you know what is causing the wrinkly leaves and dying branches. And if so, can they be saved?

This is difficult question to answer definitively for your situation. So I will ask you a lot of questions. Your answers will help you determine the plant’s problem.

When did you notice the tree was failing to grow properly? Was it kind of spindly and scraggly from the beginning or did the little tree start out healthy and grow vigorously until it reached the 6 foot level and then start the decline? If it started out sickly or smaller than the rest, it may have had a problem right from the start. If the decline started later, then perhaps the cause is some form of root damage possibly caused by an environmental factor, a physiological factor such as circling roots, a disease, or an insect problem.

Where are the trees planted? The placement of trees is very important to their long term growth. Environmental factors are usually the most frequently overlooked bit most often the cause of a plant’s problem. So examine your trees’ placement in regards to the following questions.

Are they near a sidewalk or other pavement? If the affected tree is closest to a sidewalk, it may be that the roots are not getting the same amount of oxygen, water and nutrients as its partners.  When it was a young tree, its roots weren’t as large and perhaps not covered by the
paving. Soil compaction in the root zone frequently happens when the soil is walked on frequently.

A tree near a street or driveway may be affected by the ice melting products that are either shoveled onto the root zone when shoveling snow or sprayed on by passing traffic.

Is there a walnut tree nearby? The failing tree may be coming into contact with the roots of a nearby walnut tree. Walnut trees produce a toxic substance called juglone which can poison many other plants. This is a defense mechanism for the walnut tree that helps it to reduce the competition from other plants for water and nutrients. 

Although Rose of Sharon seems to be tolerant of juglone toxicity, it may be possible that an already weakened tree may show symptoms of toxicity.

Are you near a farm field? If this little tree is the first one to be hit by pesticide drift that could possibly cause the problem. Many herbicides work by regulating the growth of the plants they come in contact with. This little tree may be getting the brunt of the drift due to its location. Again, its healthier partners may just shrug off the drift with a few lost leaves but this poor little runt isn’t strong enough to do so.

Are the trees well mulched and in well-drained soil? Do they all get about the same amount of sunshine daily? Have they been watered and fertilized at about the same rate? Rose of Sharon is a generally a very carefree plant growing in almost any soil or light condition. However, they do like full sun, well-drained soil and some additions of peat moss, leaf mold or compost to the soil.

Other factors that can cause this failure to thrive are insect borne viruses, nematode damage or a form of root rot. Have you checked the roots? Dig a bit into the soil and look for peculiar swellings or knobs on the roots. If you see these, they could be caused by nematodes. In which case, you will have to have this confirmed by a microscopic exam. This can be done by the horticulturalists at the University of Illinois Plant Clinic. In general, nematode damage is irreversible and you will have to remove the affected plant. The Plant Clinic is located on the University of Illinois campus at 1102 S. Goodwin Ave. S-417 Turner Hall. For more information, call 217-333-0519 or visit http://web.extension.illinois.edu/plantclinic/index.cfm

When you talk with them, they can tell you how to collect and send samples to them for analysis.

Speaking of plant problems, did you know that just as many- and possibly more plant problems are caused by environmental factors than by insects and diseases?

During the winter months, when planning for next growing season, think about which plants were successful in the garden and which were not. It should come to no surprise to you that the plants located in the correct environment survived the hot dry summer better than the plants that were in less than optimum places.

Categories (2):News, Living
Location (3):Local, Iroquois County, Loda

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