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Michigan Gardener | April 2022 | MichiganGardener.com
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Growing With Style Saturday, April 30, 2022 9 a.m.-4 p.m. – $50 www.mgsoc.org/educational-conference/ Nationally-known Keynote Speakers: David Culp – The Layered Garden Kerry Ann Mendez – Hydrangeas Demystified: Great Hydrangeas Plus Tips for Exceptional Flowering Shawna Coronado – Grow Up! Elevate Your Garden Beds and Stop Being a Pain in Your Neck Meredith Simpson / Richard Thomas – Oudolf Garden Detroit This is our 9th Annual Educational Conference for new and experienced gardeners – you need not be a Master Gardener to attend! Call or e-mail us with questions: Phone (248) 812-9437, E-mail: conference@mgsoc.org Registration deadline Wednesday, April 27, 2022
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When to divide perennials When is the right time to start transplanting or dividing perennials? If I wait too long, I am afraid my perennials are going to be too developed, but I also don’t want to do it too early. K.T., Kentwood Depending on the perennial, if it is starting to show some growth, dig it up as soon as you can work the soil, and then divide and transplant. That said, another approach is simply to do it when you have the time and before you get too busy with other garden chores. April, during spring clean-up, is one of the better times to divide and move perennials. During the growing season, gardeners are busy monitoring for pests, diseases, deadheading, and watering against the heat. Dividing in the spring allows the plants to grow to their new space, you to see if the placement coincides with your vision, and lets you enjoy them in their new location. Those plants you don’t get to in the spring, then divide them in the fall.
Getting rid of horsetail We have a big problem with horsetail weed, which has taken over one of our garden beds. How do we eradicate it without killing the perennials around it? P.P., St. Clair Shores Horsetail (Equisetum) should be admired for its tenacity as a living fossil. Virtually unchanged for millions of years, it thrives in those early prehistoric conditions: moist and boggy, or compacted and lean. Blessed with underground rhizomes, every time you pull or dig, any little piece resprouts a new plant. Black plastic smothering only gives them the oxygen-starved conditions they love. Applying heavy shredded mulch also provides the same moist, airless blanket. The key is to change the soil conditions it prefers. Take a hard look at the garden bed affected. First, tackle poor drainage. If needed, add a perimeter ditch around the bed to drain water away from the center. If that isn’t possible, you may need to add a length of field drain to divert the water farther away from the bed. Temporarily remove any mulch and apply dolomite lime at the rate recommended on the package for the square footage. Wait 2 weeks before amending the soil since lime and organic enrichments can conflict. Water in the lime so that it penetrates. Then determine where the low spots are and build them up with enriched compost, such as aged cow manure, leaf litter, or a balanced blend of organic compost.
You should see significant improvement in the first year, although you will see a few horsetails. Changing the soil conditions to those least preferred appears to send an evolutionary signal to cease and desist. To prevent reinfection, watch in April for the leafless fertile stems that contain millions of spores. Cut them off, put them in a ziplock bag and dispose in the garbage, not yard waste.
Yellowing yew needles The needles on some of our yews are turning yellow. Why and how can it be corrected? A.S., Canton Contrary to popular belief, evergreen needles do not stay green forever. The older, inner needles discolor and naturally drop off after one or more years. Yew needles turn yellow and drop in the late spring or early summer instead of the fall, like their deciduous counterparts. If that is the location of your yellow needles, then it is a natural process to get rid of old interior needles and sprout fresh ones. If the yellow needles are on the tips or outer branches, that can be a symptom of another cause. If yews are sheared late in the season, any resulting new growth does not have time to harden off before the temperatures drop. The tip tissue is killed and the result is yellow or browning in spring. Another reason yews begin yellowing is too much water. They don’t like wet feet or sitting in poorly drained situations (such as near a downspout). Often planted by walkways and driveways, they can get an abundance of snow load or rain run-off, which does not drain quickly due to the surrounding hardscape. They are also sensitive to de-icing salts. Poor drainage, soggy conditions and salt damage can cause root rot, which is a fungus that girdles the roots, strangling the cambium and preventing water and nutrients from reaching the outer branches. So check the location of the yellow needles. Then check the location of the plants themselves. It may be a natural seasonal process or something that warrants a physical remedy.
Weeping tree choices I need to replace a weeping cotoneaster on standard. I like the look of a single stem with a pendulous, mop-haired plant. This plant will be in a raised planter—about 2-1/2 feet high near a sidewalk. The mature width is limited to 5 to 6 feet. The mature height is unlimited. Suggestions? T.S., Garden City Most weeping tree varieties are grafted, and therefore, that is their most vulnerable spot. Southern exposure can be great,
