What is Root Rot and How Do You Prevent it?

Root Rot can be any gardener’s worst nightmare. It can be hard to properly diagnose on a failing tree, shrub, or perennial; and oftentimes it is done so too late for the plant to be saved. So what is it exactly that causes root rot and how can it be prevented in the garden or planted container? 

Cause

The main cause of root rot are several different species of soil-inhabiting, fungi-like pathogens such as Phytophthora, Pythium, or Rhizoctonia. These pathogens thrive in extended periods of high soil moisture and kill the crown and roots of plants when present in the soil. These pathogens can attack almost any type of plant that doesn’t love wet conditions and are easily spread. Vegetables, ornamental trees, and orchard plants are among the most susceptible.

Identification

There are several key identifiers that a plant will exhibit when infected with any of these pathogens. The leaves of plants will often appear stressed, wilting or yellowing as if in a drought. Branch die-back and a general lack of plant vigor are also signs of potential root rot. The base of the plant will often appear black and on some occasions there will be fungi fruiting bodies around it.  Also check the soil in the pot or area around the plant. Has it remained wet for an extended period? Is it planted in poorly drained soil? 

Management

Prevention is the best approach to managing root rots. The most important factor in reducing the threat of any of these pathogens is proper water management. Avoid prolonged saturation of the soil or standing water around susceptible plants. Irrigate only as necessary and make smart planting choices when it comes to shallow, poorly drained soil sites.

 Some root rots are treatable if caught early enough. Rotten roots can sometimes be cut out of the plant if it’s able to be bare-rooted. For larger landscape plants a specialist should be contacted to properly identify the exact pathogen causing the issue and come up with a  proper treatment plan. Fungicides are best used as preventative measures against the pathogens that cause root rot and should be applied to particularly susceptible plants such as orchard trees regularly. If root rot is evident and far along it is advised to remove and destroy the plant to avoid further spread of the pathogens.