The general rules for times to prune landscape trees and shrubs would include:

1. Dormant Season - Most deciduous trees are best pruned after their leaves have dropped in the fall and before new growth begins in the spring. When the leaves are gone, it is easier to see the structure of the tree and to imagine the long term results of the pruning. Also, the absence of leaves reduces the weight of the branches and the amount of material to dispose of after the pruning.
    

2. Bleeders - Certain trees such as maples, birch and beech will "bleed" or seep sap from the wound if they are pruned late in the winter. This is when maple syrup is gathered so you know the sap is running. These trees are better pruned in the early summer after the first flush of new growth. However, the bleeding is not a serious stress on the tree and is mostly an aesthetic concern from the stain it might leave as it drips down the bark.
    

3. Spring Flowering Trees or Shrubs - Shrubs that flower in April or May such as lilacs, forsythia, rhododendrons and others are plants that set their flower buds in the previous autumn. Therefore, pruning in the dormant season will only remove flower buds and decrease the amount of bloom. These types of plants should be pruned immediately after they stop pruning. Of course, pruning them at other times will not hurt the plants, only decrease their flowering.
    

4. Summer Flowering Trees or Shrubs - Plants that bloom in mid to late summer usually develop their flower buds in the spring. They may be pruned during the dormant season.
    

5. Either Before or After Flowering
    

6. Red Oaks - Members of this branch of the oak family are susceptible to a serious fungal disease called oak wilt. The disease is spread primarily by bark beetles moving from tree to tree. They are attracted to new, wet wounds. Therefore, these trees should only be pruned during the dormant season when the insects are not active.
    

7. Pinching - Pruning to increase the branching of the plant.
    

8. Deadheading - Pruning off the spent flowers.
    

9. Rejuvenation - Pruning to encourage new growth on plants.
    

10. Vines - Pruning for optimum flowers (Clematis) and to keep them in place.

• Mulch Pros & Cons
• Perennial Beds
• Winter Care
• Fruit Prevention
• Storing Bulbs
• Tree Wraps

• Irrigation
• Lawn Irrigation
• Trickle Irrigation
• Sprinklers

• Hose
• Containers
• Basin

• Pruning Basics
• Bonsai
• Deadheading
• Espalier
• Rejuvenation
• Timing
• Pruning Tools

• Cut Methods
• Pinching Back
• Hedges
• Pruning Lilacs
• Pruning Roses
• Pruning Mature Trees
• Storm Damaged Trees

• Tree Stumps
• Topping Trees
• Pruning Young Trees
• Pruning Ornamental Vines
• Pruning Clematis

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.