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Over the Garden Fence

How plants and pests begin preparing for fall

By this time of year, woody plants have taken care of business, meaning the foliage already has produced the energy needed to form buds for both foliage and flowers for next year. If there is a fruit or pod containing seeds, that is nearly, if not already completed, as well. In the next few weeks, plants will get the signal that fall is on the way and begin to set up for the eventual color change and leaf drop. Needled evergreens will be doing the same thing, just not as dramatic as deciduous trees.

Our perennial beds are going to be doing something similar but in different ways. Some will have a fall color; others will just yellow and fade away. For sure perennials will be sending all that last bit of energy into the root system before they die down to the ground for the winter.

Annual flowers are going to continue to grow as the weather allows, but bloom may slow with the cooler temperatures. Eventually, we will either go ahead and clean up the bed because they look poor, or we will let that first hard frost come before we clean up.

In the vegetable garden, our warm loving crops – such as tomatoes and vine crops – will slow down producing for us while fall garden choices, like Cole crops and Swiss chard, will continue to grow well into the cold weather.

Kentucky blue grass lawns are just waiting for the cooler and wetter weather to return, and soon we will see that fall flush of growth again, putting away food reserves for next spring.

Our good and bad insects are finishing up their appropriate life cycles too. Insects can have a complete life cycle (think butterflies) with an egg, larval stage, chrysalis, and adult. The other group has an incomplete life cycle with an egg, a nymph stage with growth instars, and adult (think Boxelder bugs). How those insects will overwinter will be a mixture of eggs, pupae on the host or in the soil, and adults.

Plant diseases also will be getting ready to overwinter. Many will overwinter on plant debris from the host, and others may find an alternative host plant nearby. A few easy examples impact our apple and crabapple trees. Apple scab overwinters on the leaf litter beneath and nearby, while Cedar Apple Rust will overwinter on an evergreen host, usually cedars and junipers. Both will float back to the apple and crabapple next spring. Other diseases, for example tomato foliage diseases, are overwintering in the soil, and wait to be splashed back up onto foliage the following season.

About the author: Richard Hentschel’s expertise extends across several subject areas with specialties in lawn care, fruit tree production, woody ornamentals, and home and community gardening. During his 45-year career in horticulture and agriculture, Hentschel became a well-known and respected expert for commercial and homeowner audiences, industry organizations, and media. He retired from University of Illinois Extension in April 2022 with nearly 30 years of service as a Horticulture Specialist and Educator in northern Illinois.