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TREES, SHRUBS CRYING OUT FOR A DRINK BEFORE WINTER
I watered eight trees last week. The task took six and a half hours to complete.
I ran the hose at nearly full-throttle and the water didn't start pooling under each of the six 10-foot spruce for 45 minutes. I ran the hose at the base of two 15-foot birch trees for one hour each and the ground never did get saturated. In other words - at least as of last Sunday afternoon - the ground is bone dry. How trees and plants of all kinds stay alive during prolonged periods of no rain is a mystery to me.
Until we receive at least a two-inch soaking rain, I highly recommend that you give your trees a good drink in the days ahead. The trees in greatest need of water are the ones you transplanted last fall or anytime during this growing season. Roots from these trees haven't grown much beyond the hole you dug when you transplanted them, so supplemental water is needed to ensure these trees' survival through the winter.
Trees and shrubs need the equivalent of one inch of rain per week. Since August 22, there has been a total of 0.3 inches of rain in my yard. That means my trees and shrubs - and probably yours - have been "running on empty" for too long.
It's especially important that evergreens get supplemental water during dry periods because, unlike trees that drop their leaves in the fall, evergreens transpire (give off moisture) throughout the winter. Evergreens that go into winter with thirsty roots are more likely to suffer winterburn and dieback.
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Have you observed a white powdery substance on leaves of lilac, phlox, roses, monarda, begonia, zinnia or other plants? Most likely the cause is powdery mildew, a fungal leaf disease that generally doesn't kill plants but does set them back by robbing nutrients and moisture and curbing growth and reproduction.
Powdery mildew typically appears on the surface of infected leaves as white or gray spots that dry out and often kill leaves. After becoming established, the fungus produces spores that are dispersed to other leaf tissue, causing secondary infections. Later, the fungus produces black pinhead structures called cleistothecia. These structures are able to survive the winter and cause new infections in the spring.
The disease is associated with high humidity and is often most severe on plants grown close together, grown in damp, shady locations, or grown in areas with poor air circulation.
The best way to prevent powdery mildew is through cultural practices. Increasing light penetration to plants, increasing airflow, and thinning crowded plants can all help minimize infections.
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Once the first killing frost puts an end to the growth of our vegetables and flowers, it will be time to remove all debris, including weeds, from the garden. Removing plant debris from the garden helps to control diseases and insects that are able to survive the winter on dead plant material, according to Chad Behrendt, University of Minnesota horticulturalist.
Most of this material can be composted, Behrendt says, but keep diseased material out of your compost pile unless you're certain it will reach a temperature of 130-160 degrees for two to three weeks.
Several columns ago, I mentioned that I suspected the cause of tomato blight in my potted plants this year was due to the carryover blight fungus present in the soil I used in the pots. I included compost made partially from last year's diseased plants, and some of the fungus spores most likely didn't get destroyed in the pile. My experience simply adds credence to Behrendt's advice.
If you don't compost your plant debris and want to dispose of it in some other manner than the weekly garbage pickup, you can bury it or burn it. Make sure you check first with your municipality concerning burning restrictions.
A few additional notes about fall cleanup: The more weeds you remove from your garden with their seeds intact, the fewer weeds you'll have to hoe or remove by hand next spring and summer.
You may also want to make some notes, or put markers in the soil, to indicate which annual plants were infected with fungal diseases this growing season and then not plant the same plants in that location next year.
Speaking of writing notes, it's a very good idea to write down now some of your observations and experiences from this growing season so you can review them next spring before buying, dividing or moving plants. I don't know about you, but I have discovered that my memory of last year's growing season gets pretty foggy, come spring.
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PUTTING DOWN ROOTS:
A Delightful Blend of
Gardening Wisdom, Wit
and Whimsy
$10 + $2 for shipping
by Cliff Johnson |
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