Many plants we bring home from the nursery have been growing in the same pot for months. The plants look healthy and robust, but when you slide the plant out of its container, the roots can be a circling, tangled nest. Loosening (also known as teasing or tickling) the roots before planting enables the roots to spread out and grow in all directions where they will branch out and form a good foundation for the plant. Teasing roots apart is a best practice for all plants, but it is crucial for plants that are pot bound.
What Is a Pot Bound Plant?
Often, when you purchase a plant in some type of pot or container, it has been growing in there for a good amount of time—sometimes over a year. What started as a small seedling has developed an extensive root system. Once roots have completely filled the container they are growing in, they have nowhere else to go. When that happens, the roots begin to grow around and around the bottom and sides of the pot, looking for somewhere to escape.
When a plant is pot bound, you will probably see some roots poking out of the drainage holes and maybe even above the top edge of the pot. To the novice gardener, it might seem like a bonus to purchase a plant with such a robust root ball, but in actuality, having its roots wrapped in a knot is very stressful for a plant—so much so that it might never recover, leaving it stunted or killing it outright.
If you plant a pot-bound plant into the ground or into another pot without first loosening the tangled and overgrown roots, they will continue to grow in a circle rather than reaching out into the soil to anchor the plant. It might seem like a harsh thing to do to your plants, you are actually helping them by detangling and roughing up the root ball.
How to Tease Apart Roots
Teasing roots is very similar to how you tease a hair-do; you comb your fingers through the roots to loosen the strands and increase their volume. Tease apart plant roots just before you are ready to plant. In most cases, you can loosen and detangle the roots with your fingers. Try to be as gentle as you can, but it's okay if a few roots are broken in the process. It's better to have a couple of small, damaged roots than many intact roots that are strangling each other.
If the roots are so tight that you can't get your fingers between them, try soaking the entire root ball in water for a few hours or overnight. Very often they will begin to float apart, making it easier for you to work the remainder of roots apart with your hands. You don't have to loosen every root, but try to ease apart as many as you can. After detangling you find that some roots have grown extremely long, it is safe give them a light pruning so they fit neatly into your planting hole.
In extreme cases of root-bound plants, you might need to slice through the root ball with a sharp knife or pruners in order to loosen up the roots. Do this in several places around the root ball to encourage root growth in all directions. It might seem harsh, but the plant will send out new feeder roots and should soon recover.
Annual plants, such as bedding plants and vegetable seedlings, are grown in very small containers and often come with a knotted mess of young roots that are easy enough to tease apart. However, many gardeners don't bother with annuals, because they only grow for a short season and don't need to develop a strong root system. It is perennial plants, and especially trees and shrubs, that receive the most attention and cannot be allowed to remain root-bound.
Whichever method use, be sure to give the plant plenty of water when you first plant it in the ground and for several weeks afterward. Damaged or traumatized roots require time and a bit of tender loving care to heal.