Dear Master Gardener: My lawn has been overtaken by creeping Charlie. How can I get rid of it?
Answer: Creeping Charlie (Glechoma hederacea), also commonly called ground ivy, is native to the British Isles and considered by many to be a nuisance weed in lawns. Its leaves resemble tiny geranium leaves and, in the spring, pretty and abundant tiny blue or purple flowers appear. The stems of creeping Charlie creep along the soil surface up to 30 inches in length, sending down rootlets at each node that create a mat of ground cover. This growth habit makes it difficult to eradicate.
You have some options in dealing with it. The easiest is to learn to accept and appreciate it as a ground cover. It is hardy, thick, always green and requires little or no mowing. When creeping Charlie is present in low numbers, you can remove it by hand (especially effective in the spring) or with a dethatching rake, which is a heavy and laborious task. It is crucial that you remove the roots as well as the above ground portion of the plant to effectively eradicate it. Creeping Charlie is aggressive so it may take multiple weeding events! Or, you can remove it chemically with herbicides containing 2,4-D and MCPP as their active ingredients. These herbicides will damage or kill any broad-leafed vegetation with which they come in contact, so use them with caution, following label directions carefully. The best time to spray is in the fall when no rain is forecast for 48 hours. Repeat applications may be needed every 10-14 days.
If your lawn has more creeping Charlie than grass, you may want to start over. To do that you will need to strip the sod with a sod cutter or apply glyphosate (Roundup) to kill the entire area. Applications of glyphosate are most effective on warm, calm days when plants are actively growing. Avoid windy days to ensure the herbicide does not drift onto non-target plants. Glyphosate treatments are most effective when two treatments are applied, with the second treatment taking place 7-10 days after the initial treatment. Then you can redo your lawn by preparing your soil and seeding it with high quality turfgrass to ensure dense, uniform germination throughout the area or sodding. Lawns with dense turfgrass coverage are less susceptible to weed invasion. If you do not want to use any pesticides, the U of M recommends using solarization. This involves placing a clear plastic sheet over the soil while it is warm (late spring and summer). The clear plastic sheet captures heat and sunlight, raising the soil temperatures to the point where grasses and weeds can no longer survive. Solarization works best on sunny, flat areas that are less than one-fourth of an acre. Remove the plastic in late fall when soil temperatures are 35-55 degrees so that new grass can be planted via dormant seeding.
Pink Mulla Mulla.
Contributed / Jennifer Knutson
Dear Master Gardener: I purchased an unusual annual this year called Pink Mulla Mulla for one of my containers. Some of the flowers are turning brown. Should I deadhead them and how?Answer: Pink Mulla Mulla (Ptilotus exaltatus) is an unusual annual that has recently made an appearance in garden centers. This is the first year I have seen this plant and purchased one myself! It is in the Amaranthaceae family, which is the same family as Celosia and Amaranth. It is native to the arid plains of Australia, so it is quite drought tolerant. When the spires of pink, feathery bottlebrush-shaped flowers start looking a little ratty and brown, deadhead the fading flowers to encourage new growth. Remove the flower head by cutting the stem just above a set of healthy leaves.
Yellow jacket wasps are numerous in August and are attracted to sweet, ripe and rotting food. Be watchful of cans and glasses of beverages, which may harbor yellow jackets you don’t see or expect before your next sip! Keep picking zucchini, cucumbers, snap beans and other vegetables from your garden, even if they are past their prime because the plants remain more productive. Also, the rotting produce attracts yellow jackets.Blossom end rot is a disorder that is characterized by a black, leathery sunken area at the bottom of tomatoes and peppers. Symptoms usually appear in hot, dry weather. It is caused by uneven watering which causes the minerals in the soil to not reach the fruit consistently. To avoid it, water deeply and regularly and don’t fertilize too heavily with nitrogen. Slice off the affected tissue — the rest of the tomato is perfectly good.Continue to dead-head perennial flowers to prevent seed set and enable the plant to retain more energy reserves for next year’s bloom.Divide and replant perennials that are overgrown and no longer blooming well. Discard the central part of any clump that has become woody, then replant the outer portions. Wait until spring to divide fall-blooming plants, such as mums.Iris become dormant and slow their growth this month, so now is the time to divide them if needed. Bearded iris flower better when they are regularly divided. Cut the foliage back to 6-8 inches and keep one or two foliage clusters per rhizome.Watch for enchanting sphinx moths in the early evening. They look very much like hummingbirds. They are about the same size, also flap their wings rapidly and hover, and they suck nectar from impatiens and other flowers with their long proboscises. Late summer is an excellent time to plant evergreen trees and shrubs, giving them several months to grow new roots. Evergreen trees such as pines, spruces and firs can help save energy when planted on the northwest side of your home, will provide shelter for birds, and are beautiful covered with fresh snow. It is important to water evergreens until the ground freezes any week in which we do not receive an inch or more of rain.Raise the height of your lawn mower blades to 3 inches. As heat builds in the summer the taller grass protects the roots and allows deeper root development. Shorter cut levels lead to shallower root systems, making the plants more susceptible to water and heat stress. Mid-August is a good time to plant grass seed. Warm soil and less weed competition greatly improves the chance for successful establishment before winter.Create a compost pile with grass clippings, leaves, garden debris (plant material), egg shells, and fruit and vegetable scraps. Warm August weather encourages the rapid breakdown of materials by bacteria. Keep it moist and turn it frequently to maintain an aerobic environment to speed up the breakdown process. According to the EPA, home composting can divert 700 pounds of waste per household per year from municipal waste. And, you’ve just created your own “gardener’s gold” to enrich your soil!
You may get your garden questions answered by calling the new Master Gardener Help Line at 218-824-1068 and leaving a message. A Master Gardener will return your call. Or, emailing me at
umnmastergardener@gmail.com
and I will answer you in the column if space allows.
University of Minnesota Extension Master Gardeners are trained and certified volunteers for the University of Minnesota Extension. Information given in this column is based on university research.
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