Your Garden … with Kate Russell: Root washing aids gardeners in replanting at proper depth

Root pruning stimulates growth the same way above-ground pruning does

By Kate Russell

Kate Russell

Why on Earth would you want to wash off a plant’s roots? Don’t roots prefer being covered with soil?

Well, they do. But root washing is an excellent way for Gilroy gardeners to see what a root system looks like so you can correct problems before they become fatal. While the delicate roots of tender annuals and seedlings should always be handled with care, woodier roots can withstand a surprising amount of harsh treatment and are often healthier as a result.

There are many good reasons for root washing. Being surrounded by the wrong soil, delivered in foreign soil, or delivered wrapped in burlap, can all lead to problems. Very often, mass-produced trees and shrubs are root bound by the time they reach market. Left uncorrected, these roots can kill the plants. Washing the roots allows you to identify the primary roots and prune out any problems. To wash roots, start by removing any packaging and shake as much soil loose as possible. If necessary, soak the root ball in water to loosen the soil. Then gently hose off the remaining soil. Now you can inspect, prune, and replant.

Root pruning stimulates growth the same way above-ground pruning does. Look for and remove any dead, damaged, mushy, or circling roots. Knotted roots, J-hooked roots, and other deformities should also be removed. These roots are likely to cause problems later in the plant’s life. Once a root system has been inspected and pruned, it’s time to replant in new soil, to avoid soil interface issues. Soil interface refers to what happens to roots when they come into contact with a different type of soil.

Very often, what’s used in mass-produced plants is a soilless mixture that contains a lot of pumice and organic material. You might expect plants would simply move into the new soil in search of food and water, but they often don’t. When this happens, the plant usually dies.

The same thing can happen when you transplant summer annuals from high quality potting soil into more compacted, residential soil. Washing roots and installing the plant in new or resident soil eliminates this problem.

Root washing helps you replant the newest member of your Gilroy landscape at the proper depth. Bagged and packaged plants are often surrounded with extra soil, which does not mark proper planting depth. Planting trees too deeply is one of the most common causes of tree death. The outward flare of the trunk should be visible above the soil line. Help your plants thrive with root washing and proper planting depth.