I’ve heard that fall is the best time to plant trees. Is that true? DB

Oftentimes when we tell people that the best time to plant trees and shrubs is in the fall, we get questioning looks. However, in spite of that apparent uncertainty, yes, fall is the best time to plant most trees and shrubs. Let me explain.

The first and most important thing that newly planted plants (including trees and shrubs) need to do is develop a healthy root system. The smaller the plant, the quicker this usually happens. But since trees and shrubs are usually larger than the annual and perennial flowers we plant, it takes them longer to develop a root system capable of anchoring and feeding these plants. So, when we plant trees and shrubs in the fall, while the above-ground portion of the plant is dormant, or at least not very active, the tree or shrub is free to concentrate of growing roots. When they have the fall, winter, and spring to develop a healthy root system, they will be better prepared to survive our Oklahoma summers. Trees and shrubs can be successfully planted at other times of the year, but you will really need to increase the amount of time you spend watering the new arrivals to your landscape to help them survive. If they have a good root system, their summer water needs will be diminished.

Trees and shrubs are available in three different ways: bare root, container grown, and balled and burlapped. Bare root trees are usually those you order from a catalog. Bare root trees should be planted from mid-February to mid-April but many of the planting rules are the same. One of the critical things for bare-root trees is that you keep the roots moist until they are planted.

The trees you will find in local nurseries come in two varieties: container grown and balled and burlapped. Container grown trees have spent their entire life in the container, so they have a head start on their root system. Balled and burlapped trees have been grown in the soil but then dug up by a claw-like device attached to a large tractor. This process cuts all the roots outside of the radius of the device, so they really need to grow a new root system and do it pretty quickly. Container grown trees and shrubs will do a little better when planted at other times of the year since they already have a decent root system. But, balled and burlapped trees will need the extra time to grow a proper root system.

Whether it’s balled and burlapped or container grown, the planting strategy is the same.

When planting, the first thing you will need to do is dig an appropriately sized hole. Now a lot of you are not going to like this recommendation, but don’t just dig a hole the size of what you are planting. You need to dig the hole about 3 times wider than the size of the existing root ball. I know this is more work and for most of us, digging is not one of our favorite activities, but you paid good money for this new plant, it’s best to go the extra mile to give it the best shot possible. Here’s why we dig a larger hold.

As you dig the hole you are going to notice that the soil is compacted (this is another way of saying “digging is hard”). If we only dig a hole the size of the root ball, the new, young, tiny roots that will be reaching out from your new tree and going to have a harder time reaching out into compacted soil that they would if the soil had been loosened for them. So, it’s a good practice to dig the hole 3 times wider than the root ball of whatever you are planting. This way then entire area has been loosened up for the soon to be growing roots.

This extra digging only pertains to the width of the hole though and not the depth. You don’t want to dig a hole that is deeper than the root ball because the packed or compacted soil underneath the root ball will help to minimize settling. Ultimately, you want the top of the root ball to be slightly above grade, so you won’t end up with a pond around your tree. If you are planting a balled and burlapped tree, you should remove the burlap and twine before planting.

Once you have you tree placed at the proper depth in the hole, it’s time to fill in the hole with the soil that came out of the hole. It is not necessary to add compost or amendments to this soil because you want your plant to get used to its new home in it’s natural state and not get pampered with super soil around its roots.

Next you will want to place a layer of mulch around your plant. This will help keep the soil moist and prevent water run-off. Some trees may require staking. If they do, be sure to support them loosely as the movement will help strengthen the young tree.

Now it’s time to water it in. You will want to keep it watered through the Fall and Winter since they will need about an inch of water per week.

This entire process may be more that you were expecting, but if you follow these steps, you will be well on your way to enjoying these new additions to your landscape for years to come.

You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at mg@tulsamastergardeners.org.

Photo: Anthony LeBude, NC State University, Bugwood.org