Additional Notes: Fall Landscaping

By: Rebecca Konopka
Carter County Extension Officer

We often hear that fall or winter is a particularly good time to do certain things in the landscape. This is usually because the plants have gone into winter dormancy.

Dormancy can be compared to a long period of “rest” for plants, when they are relatively inactive in terms of metabolic processes (photosynthesis, respiration and transpiration, for example). I say relatively inactive because although these processes slow down during dormancy, they do not completely cease. Most temperate perennials go dormant in the fall as daylight becomes shorter, temperatures (including soil temperatures) become cooler, terminal buds form, and possibly due to warmer conditions. dry in late summer and fall.

Dormancy is how these plants survive the winter cold. It is important that landscape maintenance activities do not interfere with the plant’s natural dormancy process. Consider pruning and fertilization practices as examples.

Fall is considered a bad time to prune most woody perennials. Pruning will remove terminal buds which help maintain dormancy in many species. The presence of the terminal bud, even in an apparently inactive state, suppresses the growth of lower buds by a process called apical dominance, a type of dormancy imposed on lateral buds. If you remove the apical bud, it may encourage side buds to initiate growth in a plant that has not yet fully entered a dormant state. Once lateral bud growth is initiated, dormancy will be difficult to achieve, even with the advent of shorter day length and cooler temperatures. Thus, pruning in the fall can trigger new growth that delays dormancy and predisposes the plant to winter injury.

Plants are best pruned in late winter, around mid-February to mid-March. It also allows you to assess and remove winter damaged limbs. Late winter pruning will take place just before one of the most active periods of plant growth, bud break, when the plant redirects stored nutrients from the root system to the branches. This would be the fastest time for the plant to heal wounds (in our case, the pruned surface), while fall would be the slowest time for wound healing. An exception is if you are removing dead or severely damaged limbs due to breakage, insects or disease. In this case, it is better that you remove them as soon as possible at any time of the year. If the plant you are pruning is a spring bloomer (usually flowering before early June), it would be best from a flowering standpoint to wait until after flowering to prune, as the pruning process will remove pre-existing flower buds.

What about fertilizing woody plants? Fall and winter are considered the best times to apply fertilizer, but you should only do this when woody plants are completely dormant. Otherwise, applying fertilizer could trigger new growth and predispose the plant to winter injury.

How do you know if a plant is dormant? If the leaves are dropping, the plant has probably gone dormant enough to allow fertilization. To be doubly safe, wait until temperatures aren’t likely to climb into the 70 degree range. In Kentucky, it can happen anytime from mid-October through mid-November, so to be absolutely sure, it probably means mid-November or later. It’s best to put the fertilizer in before the ground freezes so that it doesn’t sit on the soil surface and become subject to runoff with additional rainfall.

If you don’t fertilize between Thanksgiving and Christmas, wait until the ground thaws in late February or early March to apply the fertilizer. However, be aware that February and March are not the best times to fertilize lawns made up of cool-season grasses (fescue, bluegrass and perennial ryegrass). If you regularly apply fertilizer to your lawn, woody plants growing nearby are likely getting enough nutrients from those applications and probably don’t need additional fertilizer.

For more information on fall landscape maintenance or other gardening topics, contact the Carter County Cooperative Extension Service. The educational programs of the Kentucky Cooperative Extension Service are for all people, regardless of economic or social status, and will not discriminate on the basis of race, color, ethnicity, national origin, creed , religion, political beliefs, sex, sexual orientation, gender identity, gender expression, pregnancy, marital status, genetic information, age, veteran status or physical or mental disability.

upcoming events:

  • The Grayson Farmer’s Market is open Saturdays from 9:00 a.m. while supplies last. The market is located in the hangar behind the extension office. The Olive Hill Farmer’s Market is open Saturdays and Wednesdays at 8:00 a.m. and Mondays at 3:00 p.m. while supplies last each day. Olive Hill Market is located in the Save-a-Lot parking lot.
  • Hay sampling is underway for the East KY Hay Contest. Dial 474-6686 before September 19e request a sample.
  • Field day on the farm and with the family – Thursday, September 8e – Farm by Matt & Tracy Prichard
  • Carter County Expansion District Board Meeting – Tuesday, September 13e @ 11:00 a.m. at Carter County Extension Office
  • Hike and Learn – Friday, September 16e @ 1:00 p.m. – Grayson Lake Spillway

About Antoine L. Cassell

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