Winter Tree Care

Which season is the best time to prune deciduous trees? If you guessed winter, you would be right! This is because damaged limbs and the presence of pests are more clearly visible during the winter after leaves have fallen off the tree.

During the dormant or winter season, a tree without leaves allows an arborist to inspect the tree canopy for limb damage, and make recommendations for pruning or removal. The arborist will also inspect the structure of the tree and branches. Pruning may be recommended to increase airflow through the tree canopy to help prevent storm damage when leaves return on the tree. Trees that sustain damage from storms are more likely to be subjected to insect damage and disease pressure.

But before you do any pruning or tree work, the first step is to contact a certified arborist who is licensed in the State of Maryland, to perform the tree work.

The Maryland Department of Natural Resources is the state agency that licenses companies that perform various types of tree maintenance. You can find a list of tree companies licensed to perform tree maintenance in the State of Maryland using this link: The listing indentifies companies that have ISA (International Society of Arboriculture) certified arborists on their staff.

Winter is also a good time to inspect trees for signs of disease presence or insect damage.

If the arborist identifies a pest presence, control measures may be recommended prior to leaf growth in the spring, or dormant pruning for certain species of trees, which are susceptible to insect vectored diseases. Insects that carry harmful tree diseases (i.e. Dutch Elm or Oak Wilt), are less active during cold winter weather, thereby enabling recommended pruning. Dormant pruning will permit callous tissue to begin sealing the pruning cut before spring growth begins and insect pests become active. Some tree species that are pruned during the warmer months of the year may become susceptible to invasion of diseases or insect damage due to increased pest activity. This is because the sap on the freshly cut limbs and branches will attract insects such as beetles and emerald ash borers that are harmful to Oaks and Ash trees. Trees in the rosacea family such as pears, apples, shadbush, and hawthorns should also be pruned during the dormant season to help reduce the spread of bacterial fire blight disease.

If the arborist recommends a control treatment, only hire firms licensed in the State of Maryland to perform the pesticide applications. A list of companies who are licensed in the State of Maryland to perform pesticide applications can be found at Several tree care companies are licensed to both perform tree inspections and apply pesticides to treat identified conditions.

From the City's Tree and Landscape Board