This field guide outlines species-specific pruning timing recommendations for Northern Virginia based on tree biology, disease pressure, and risk considerations. 

Northern Virginia (USDA Zones 7a–7b)

Rule of thumb:

Prune based on species biology, disease risk, and objectives — not convenience.
 

Dormant season is often best, but not always.

Red oak · White oak · Pin oak · Willow oak

✔ Best:

• Dormant season (Nov–Feb)
   

✖ Avoid:

• Apr–Jul (oak wilt vector period)
   

Field notes:

• Emergency pruning OK anytime
   
• Seal cuts only when oak wilt risk is active
   
• Favor structure + clearance over aesthetics
   

Red · Silver · Sugar

✔ Best:

• Dormant season
   
• Late summer–early fall
   

⚠ Notes:

• Spring pruning causes sap bleeding (cosmetic only)
   
• Structural pruning easier in dormancy
   

✔ Best:

• Late winter (Feb–early Mar)
   

✖ Avoid:

• Topping (“crape murder”)
   
• Summer reduction cuts
   

Field notes:

• Light structural correction only
   
• Remove crossing, dead, inward growth
   

✔ Best:

• Late summer
   
• Dormant season only in dry conditions
   

✖ Avoid:

• Wet spring pruning
   

Critical:

• Sanitize tools between trees (black knot, bacterial canker)
   

✔ Best:

• Dormant season
   

✖ Avoid:

• Apr–Aug (Dutch elm disease vectors)
   

Pine · Spruce · Fir · Arborvitae

✔ Timing by type:

• Pines: Late spring (candle stage)
   
• Spruce/Fir: Late winter–early spring
   
• Arborvitae: Early spring or mid-summer
   

✖ Never:

• Cut into non-green wood
   

✔ Best:

• Immediately after flowering
   
• Late summer
   

✖ Avoid:

• Heavy dormant pruning (flower loss)
   

✔ Best:

• Late summer–early fall
   

⚠ Notes:

• Heavy sap bleeding if pruned late winter
   

Best for:

• Structural correction
   
• Deadwood removal
   
• Risk reduction
   
• Trees over targets
   
• Large-canopy work
   

Advantages:

• Clear defect visibility
   
• Reduced pest activity
   
• Lower physiological stress
   

• Immediate risk exists
   
• Dead/broken limbs present
   
• Storm damage occurs
   
• Inspection confirms urgent defects
•  See real-world pruning and inspection case studies
   

• Preserve branch collars
   
• Match cuts to species response
   
• Sanitize tools when disease is present
   
• Inspection precedes action
   
• Timing supports — but never replaces — judgment
•  This guide is intended for educational use and does not replace on-site inspection or professional judgment.