Plant Shrubs in Autumn

By C. Rae Hozer, Cumberland County Master Gardener

Question: “We have evergreen shrubs that died from drought or the freeze or from some unknown cause. We would like to replace them. Is it better to do this in the fall or the spring? Any suggestions as to what plants to get?”

Answer:  Most perennial plants with woody stems can be put in any time when the ground is not frozen. However, landscape and horticulture experts say shrubs and trees planted during the autumn months have an advantage over those installed in springtime.

Woody plants need good roots to bring in enough water and minerals to support both above– and below-ground growth. Balled and burlap (B&B) specimens are dug from fields where they’ve been raised. Lots of roots get left behind. Trees and shrubs grown in containers have little extra space in their pots for roots from the get-go. The health and vigor of newly located landscape specimens depend in part on how well their root systems develop. The earth stays warmer than the atmosphere as days grow shorter from September through November. Soil temperatures below the surface stay sufficiently high for root development throughout a typical Tennessee autumn. There is no need for new leaves or branches so all of the transplant’s resources can be devoted to roots in the fall. On the other hand, the air temperature rises more quickly than that of the ground during the spring months. Trees and shrubs set out too early just sit and wait until the soil warms enough for root growth. In addition, spring transplants must split their energy between putting out new shoots and leaves and establishing roots.       

The first consideration in shrub selection is homeowner preference. What attractive shrubs or small trees have you seen growing in your community? Make new friends while learning about plants you admire: stop and ask the folks who live there for names of plants growing in the yard. Do research before purchasing a specimen with appealing looks from a catalog or bringing one home from a garden center or nursery. Be sure it is winter hardy here. Match each plant’s needs and characteristics to the site. How much sunlight must it get each day? Is morning or afternoon sun better? What are the moisture requirements? Shade plants often want both less sun and more water, but a few prefer dry shade. Though some shrubs are drought tolerant when mature, they typically need extra water during the first one or two years at a new location. Irrigation may be required while they establish a good root system. Will the plant’s mature height and spread fit into the space available? Don’t create a maintenance nightmare by getting shrubs that must constantly be pruned to keep them smaller than their natural size.   

Once you’ve found a shrub whose looks you like which also matches conditions in your yard, don’t go overboard. A mixed border with species variety is a better than having many plants of the same species near each other. Mono-cultures often lead to landscape headaches. Why just one or two arborvitae, Leyland cypress, or junipers in a single species grouping always die, is one of nature’s mysteries. The empty spots really show up and can make the whole landscape look out of balance. Too many of a single species planted close together also increases the risk that an infection or insect infestation which hits one will more easily spread to the others.

Use proper planting techniques. Planting too deep is the number one mistake made when shrubs and trees are transplanted. The planting hole should be no deeper than the root ball!  

Plateau Gardening is written by Tennessee Master Gardeners about home landscapes and gardening in our state’s Upper Cumberland Region. For answers to specific yard and garden questions or to learn how to become a Master Gardener contact UT Extension Cumberland County, P.O. Box 483, Crossville, TN 38557, (phone 931-484-6743). Email inquiries to “mgardenerrae@frontiernet.net”. Email questions may be answered either individually or through future newspaper articles.