Why Will Plant Roots Not Develop Out of the Container Shape?

Adventitious Roots

• If you diligently water your container plant, the adventitious roots simply grow toward any available moisture. With a moist soil environment throughout the pot, roots continue to grow into a circle shape as the stem and foliage grow larger aboveground. Regardless of the container's material construction, the walls become a barrier, unless roots accidentally grow near a drainage hole. Quite often, you may not notice it is time for a transplant until the roots are so tangled that they grow right out of the holes, creating numerous appendages susceptible to drought and decay.

Root Growth Stimulation

• Container-shaped roots are often undisturbed when moved from the pot to the outdoor garden -- they have no immediate need to stretch their roots into the deep ground. To combat root girdling that leads to plant dieback, you need to stimulate the roots. For example, moving a tree from one side of your garden to another often involves root cutting. This damage to the roots tells the plant that it needs to grow new roots for nutrient and water absorption. As a result, the plant harnesses its energy toward root development.

Shearing and Loosening Roots

• Although root stimulation used to be confined to cutting four slices out of the root ball's sides, shearing is now more pronounced -- you need to cut up to 1-1/2 inches off the root ball's surface for adequate root stimulation. In essence, you encourage new root development by removing part of the root ball, if the roots are woody and large. As a result, new roots grow out of the cut area and into the surrounding soil. However, if you are moving plants from one container to another, you must perform this root pruning technique each time you transplant -- your plants eventually have normal root structures without the exaggerated container circling. Plants with fine roots should not be sheared. In fact, a simple loosening with the hands should be enough stimulation to help the plant grow normal root structures in the new location.

Moisture as Bait

• To encourage roots to grow outward after transplanting the plant, irrigate your soil deeply. Roots naturally grow toward moisture -- if you water lightly, creating a shallow moist area, roots grow toward the surface. By watering deeply and widely, your root ball slowly extends outward for sustenance. Keep an organic mulch on the topsoil as well to retain the moisture for better root establishment and plant health.