Q. As plants in my garden begin to green and produce new growth, I've noticed that some of my evergreens are very brown. Is this a disease? What should I do?
A. The Chicago area experienced a very harsh winter this year. Extremely cold temperatures that rarely climbed above freezing and a large amount of snow kept plants continually dormant without the usual freezing and thawing cycle. Plants are unable to take up water through their roots during harsh winters. Evergreens, both needle and broadleaf, continue to lose water through their foliage, even during the coldest winter months.
When a plant's foliage transpires water faster than its roots can absorb it, foliage browns and the plant suffers from what is known as winter burn. Holly (Ilex), yew (Taxus), and boxwood (Buxus) plants were among the worst damaged this season. Dead stems should be pruned away in late spring. Determine if they are dead by gently scratching the stems. If green tissue shows, the stems are still alive and will not need pruning. Brown foliage will eventually fall on its own, or it can be trimmed. One way to minimize or prevent winter burn in the future is to make sure the plants are well hydrated going into winter. Applying a 2-inch layer of mulch will help retain moisture. If possible, small plants can be wrapped with burlap to protect the foliage. Also, planting evergreens in the spring and watering them consistently will give them one entire season to become established and a better chance of preventing winter burn.
Read more in our blog, "Overcoming Winter Scorch" by director of horticulture Tim Johnson.
Please contact Plant Information Service at (847) 835-0972 for more information.