Fall Perennial Care

Fall is coming and hopefully we are on the downhill slide as far as temperatures go. With the cooler temperatures we have an opportunity to complete some tasks that we haven’t felt like, or been able to do with the heat that we have had over the summer. As temperatures cool it’s time to give our perennial flower beds some care and attention. There are several tasks that we can accomplish over the next few months that will help our perennials and ornamental grasses thrive for years to come.

If your perennials didn’t bloom as well this year or they are getting too big for their space, fall is an excellent time to dig your perennials up and divide them into smaller clumps. Some perennials, such as daylilies, really do best if divided every four to five years to maintain flower production and while others need dividing to keep them somewhat in check. Other plants such as ornamental grasses will develop a dead spot in the middle if not divided periodically to maintain the vigor of the plant. September is an excellent time to dig these plants up and divide them into smaller clumps. Use a sharp spade and dig the entire clump up then use the spade to cut the clump into smaller pieces. Make sure each clump is at least 6” to ensure enough root system to create a vigorous new growth. You can then plant one clump back in the original spot and use the others in different spots in the yard or give them away to friends to expand their garden.

Peonies are a spring favorite of many people. While a peony can be left in one spot indefinitely and continue to grow and thrive you can divide them to expand your peony collection or move them to a new spot. Peonies are easy to divide in the fall because they have essentially gone dormant by mid-August even if the leaves are still green. To divide a peony, you should first remove all the foliage and then dig the entire plant up. Shake or wash all the soil off the clump till you can see the pink buds or “eyes” of the plant. Unlike dividing other perennials, you will need to use a sharp knife to cut up the peony roots as they are very tough. Make sure each clump has at least 3 eyes but four would be best. Plant the new clumps in locations that get at least a half day of full sun, but the more the better overall. Make sure the pink buds are only an inch below the surface. If planted any deeper you might delay flowering or there will be no flowers at all.

While it might be tempting with the cooler temperatures to fertilize your perennials this fall, it’s best to wait. In the fall we want our perennials to be preparing to go dormant which means you want to prevent lush thick growth going into the winter months. It is important to continue to water perennials unless we start to receive rainfall but hold off on the fertilizer.

Now is also the time to be watering our spring blooming shrubs such as lilacs, forsythia, mock orange and others as they are currently setting their bloom buds for the spring season. Water once or twice week deeply as opposed to every day with just a little bit of water for the best results.

While it’s easy to forget about the fall tasks there are a few things we can do now that will help our plants thrive through the winter and into the next growing season. Take this fall time to expand your perennial garden by dividing plants or give a gift to friends to help them get started on their gardening journey.

Have questions? Contact our office where our Horticulture Extension Agent will assist you with questions.

Phone: (316) 321-9660

Email: callae@ksu.edu