Now that the Iowa State Fair is over, schools are starting again, and garden produce is at peak; it is time to turn thoughts toward the autumn weather ahead. Fall is one of my favorite times of year, but also bitter-sweet, while thinking about freezing temperatures and when gardening efforts must be regaled to inside the home.

And unfortunately, looking back at weather history, there is even the slight potential that our first frost could arrive in the next month! Now is the time to start preparing plants for cooler weather ahead, in order to help prevent possible damage or winter-kill of perennial plants and shrubs.

Discontinue fertilizer application on perennial plants and shrubs. Fertilizer, especially the slow-release types will continue to encourage the plant to put out new growth. New plant growth is tender, and thus more susceptible to winter dieback, when the freezing temperatures arrive. Plants need time to “harden-off”, by stopping new growth, and putting energy into reserve for the winter months ahead.

Pruning plants such as roses and arborvitae also encourages new growth, and thus increases the possibility for winter dieback to occur. Avoid pruning actively growing plants to encourage winter shutdown to occur. Prune in early spring for best results.

Continue to keep perennial plants and trees well-watered and mulched until the ground freezes. This will help plants to avoid stress and go into the winter in a healthy state – which aids their probability of winter survival.

Did you know? Our bodies make Vitamin D from being outdoors in the sun, and we also obtain it by eating foods supplemented with Vitamin D. But most folks living in Iowa probably could use more Vitamin D in their diet, especially when shorter days of fall arrive. Check with your medical provider for further information on your Vitamin D needs, and information on how to avoid low Vitamin D levels when spending less time outdoors.

Horticulture Questions? Contact McCormick at yvonne@iastate.edu for information or advice.