While spring is generally considered the ideal time to plant trees and shrubs, many woody ornamentals do quite well when planted in the fall. Some experts consider fall to be a better time to plant spruces and pines than in the spring.
When considering whether to plant a tree in the fall, check to make sure your tree isn’t one that is slow to establish roots. These trees are susceptible to being heaved out of the ground by the freezing and thawing of the ground over the winter. Some species to avoid include; Red Maple, Birches, Flowering Dogwood, Hawthorns, Tulip Tree, Tulip-poplar, Magnolias, Black Gum, Poplars, Stone fruit (Peach, Cherry, etc.), White Oak, Scarlet Oak, Bur Oak, Willow Oak, English Oak, Red Oak, and Willows. However, if you find one of these trees at a bargain price, it may be worth the risk. Sometimes they will survive just as occasionally a tree suited for fall planting won’t make it through the winter. Just don’t be overly disappointed if it doesn’t make it.
Once you have selected an appropriate site and determined that you have a species suitable for fall planting, here are some tips for planting your trees or woody shrubs.
The first thing to remember is to select only container-grown or balled-and-burlapped trees. Bare-root plants should only be planted in late winter or early spring while the plants are dormant. Remember to only handle trees from the container or root ball; do not pick them up by the trunk as this can cause injury due to the weight of the roots.
Avoid planting large trees in the fall. They can be risky to transplant in any season, but are particularly so when foliage is present. Leave the large trees until spring, and have a professional do the work. They have the proper equipment and expertise to help ensure a safe move.
Plant trees and shrubs early enough in the fall for the plant to develop a good root system. This serves two purposes; establishing the tree in its new location so it is less susceptible to winter heaving, and getting it off to a good start during the next spring. Soil temperatures should be well above 55 degrees at a depth of six inches at planting time. This condition usually exists until the middle of October and sometimes later in warm autumns.
Follow all normal tree planting recommendations. The planting hole should be three times as wide as the root ball and the backfill should not be amended. You want the area around the tree to return to the same condition as the surrounding soil as quickly as possible. Amending the backfill can result in a less compact area. This can fill with water and drown the tree.
Be careful not to plant too deeply. You should clearly see the root flare above the surface of the ground. The most common problem I see with trees is when they are planted too deeply. This tends to promote the development of something known as a girdling root which circles around and can eventually strangle the tree. Even without this problem, the roots will have a hard time getting enough oxygen if they are too far below the surface.
Apply two to three inches of mulch, no more, around the base of the tree, and avoid mounding it against the trunk. Staking trees for support can be helpful for tall trees but is not necessary in all situations. The trunk should be able to sway with the wind; the problem is when the root system moves. While fertilizing at planting is useful in spring, avoid this in the fall as it may cause trees to produce new foliage which will actually cause stress.
Water as needed to supplement rainfall. The tree should receive about one inch of water per week over the root zone, in a single, deep watering. Continue weekly watering until the ground is frozen, even after deciduous plants have lost their leaves. Wrap the trunks of thin-barked, young trees in late November to prevent frost cracks, sunscald and animal damage, but be sure to remove the wrap in March. Next year, continue to water these trees as if they are first-year plants.
For additional information see Purdue Extension publication HO-100-W, “Planting & Transplanting Landscape Trees and Shrubs,” by Purdue Horticulture Specialists Michael N. Dana and Rosie Lerner. It is available online at: https://www.purdue.edu/hla/sites/yardandgarden/wp-content/uploads/sites/2/2016/10/HO-100.pdf.