I recently heard a colleague remark, "The cracks in my yard have cracks." In Illinois, spring and fall typically bring reliable rainfall.
Fall of 2017 is off to a dry start. There has been little rainfall in the last month, and we experienced high temperatures the last few weeks. Our cool season lawns should be growing annoyingly fast. My mower should be cutting the lawn at least once a week. In the last five weeks, I've mowed my lawn one and a half times.
Late summer to early fall is also a good time to overseed, renovate or start a cool season lawn. Again, the fall weather is ideal for cool season turf grasses. This year, if you are not irrigating newly seeded lawn, it likely will not successfully establish and survive the winter.
Cool season perennial lawn weeds are best treated in the fall because they readily take up herbicide that translocates to the root system and kills the entire plant. With the hot weather, cool season weeds are not growing as normal, and herbicide will be less efficient. Our window for treating weeds closes about mid-October, and we may still be in the same situation.
Evergreens are another landscape plant for which fall precipitation is critical. By holding their foliage through the winter, evergreens continue to lose water. Frozen soils do not permit evergreens to replenish that loss. Evergreens going into winter after a droughty fall run the risk of severe winter burn of foliage, stress and perhaps the outright death of the plant.
Here are tips when dealing with fall drought:
º Water newly planted trees, shrubs and perennials. Trees especially take a long time to become established, upwards of two years depending on the species and site conditions. A plant without an established root system is highly susceptible to drought stress.
º Evergreens, both newly planted and established, require irrigation during a drought. Leave a dripping hose at the base of the evergreen for several hours at least once a week. A bucket with holes in the bottom does the same trick.
º Irrigating in the fall provides the necessary moisture to keep the lawn green and actively growing. Apply about an inch of water per week.
º Mulch is great for insulating soil from temperature extremes and conservingmoisture. Two to four inches of wood chips are adequate, but mulch should never touch a tree or shrub.
º Irrigate fall-blooming plants. Drought reduces the flowering of fall-blooming plants, and pollinators need that critical nectar source.
I wish there were a crystal ball to tell us exactly when the rains and cooler temperatures will return. The best we can do are computer models for predictions. As of now, the models suggest temperatures will cool to more seasonal levels, but we will remain dry. There is no significant rainfall in the long-range forecasts until November. By then it will be too late for our lawns, and depending on how low the temperatures fall, it may be too late for our evergreens.
At least the poison ivy looks good right now.