Fall is ideal for planting perennials, trees, and shrubs, and for dividing perennials like peonies, irises, and daylilies. Cooler air and shorter days reduce plant stress, and the warm soil fuels root growth, allowing plants to focus on building strong root systems before winter. Perennials planted in the fall continue to grow roots until the soil freezes. By spring, they emerge with earlier blooms, vigorous growth, and greater resilience to summer heat and drought than plants transplanted in spring.
When dividing plants, look for a suitable place. The right place might seem difficult, but it is simply a matter of choosing a plant to the location where it will be grown. If a perennial isn’t thriving where you planted it, has overgrown its space, or is too small and overwhelmed by its neighbors, now is a great time to move it to a better location. You can move and divide spring and early summer blooming perennials in the fall, but plants that bloom in late summer or fall are best moved in the spring. Ornamental grasses are also easier to divide in the spring. Finish moving plants at least four to six weeks before the ground freezes, so the roots will have time to establish.
Take care when moving a plant. Use a sharp shovel and dig just outside the plant’s root zone – usually the outer edge of the foliage- keeping the root mass as intact as possible. Set the plant into a new hole that’s two to three times wider than the roots, but equal to the original growing level. Skip adding compost or extra organic matter; research shows it can keep roots in the planting hole and prevent them from spreading out into the native soil. Ultimately weakening the plant. Firm the soil gently around the roots, then water thoroughly to settle the plant and remove air pockets. Wait until spring to apply fertilizer. Finally, mulch with a couple of inches of organic material such as bark chips or leaves.
A plant’s roots continue to grow until ground temperatures drop below 40 degrees, so it is important to keep watering perennials, trees, and shrubs until the soil freezes. Skip high-nitrogen fertilizers in the fall, as they trigger tender new growth that frost damages easily. However, applying compost or worm castings in the fall adds nutrients and increases soil health. Apply a fresh 2- to 3-inch layer of straw, shredded leaves, or wood mulch after nighttime temperatures drop to freezing, keeping the mulch slightly pulled back from the main stems.
Fall is also a good time to reflect on your garden and start planning for next year. Consider starting a Garden Journal – a place to keep notes, observations, plans, photos, successes, and failures – anything that relates to your garden. How you organize your garden journal isn’t important – the goal is to have a place to record all your important observations as the seasons go by. You can review your notes from previous seasons to determine what worked well and what didn’t, helping you make more informed decisions for next year. You can also use it to track plants you’d like to add, areas you want to redesign, and spots in the garden that could benefit from improvement.
By Jeanne Yeoman, Nebraska Extension Master Gardener Volunteer
