Norway Maple Maintenance
Norway Maple is a widely planted shade tree known for its dense canopy and deep purple-leaf cultivars. In Colorado, it often struggles with alkaline soils, heat stress, chlorosis, verticillium wilt, girdling roots, and several insect pests. It performs best in cooler, moist, well-drained soils.
- Species
- Norway Maple
- Botanical Name
- Acer platanoides — includes cultivars like ‘Crimson King,’ ‘Emerald Queen,’ ‘Deborah,’ ‘Royal Red’
- Group
- Deciduous Trees
- Tracked Problems
- 8
Seasonal Calendar
| Problem | Type | Active Season |
|---|---|---|
| Aphids | Insect | Spring–Fall |
| Scale insects | Insect/scale | Spring crawlers; visible year-round |
| Maple borers | Insect/borer | Summer |
| Leaf spot / anthracnose | Fungus | Spring–Summer |
| Verticillium wilt | Fungus | Spring–Fall |
| Chlorosis | Abiotic | Spring–Summer |
| Leaf scorch | Abiotic | Summer–Fall |
| Girdling roots | Structural/abiotic | Visible year-round |
Pest & Disease Guide
Aphids
Common symptoms
- Sticky honeydew
- Sooty mold
- Leaf curling
Treatment & management
- Hose-rinse foliage
- Encourage beneficial insects
- Treat severe outbreaks
Scale Insects
Common symptoms
- Hard or cottony bumps
- Branch dieback
- Yellowing canopy
Treatment & management
- Treat crawler stage
- Apply horticultural oil
- Prune infested branches
Maple Borers
Common symptoms
- Exit holes
- Branch dieback
- Sawdust/frass
Treatment & management
- Reduce stress
- Deep water during heat
- Preventive sprays if needed
Anthracnose / Leaf Spot
Common symptoms
- Brown blotches
- Early leaf drop
- Distorted leaves
Treatment & management
- Rake leaves
- Improve airflow
- Rarely needs treatment
Verticillium Wilt
Common symptoms
- One-sided wilting
- Sapwood discoloration
- Progressive dieback
Treatment & management
- No cure
- Prune affected limbs
- Support tree vigor
Chlorosis
Common symptoms
- Yellow leaves with green veins
- Reduced growth
- Thinning canopy
Treatment & management
- Iron injections
- Soil treatment
- Improve drainage
Leaf Scorch
Common symptoms
- Brown crispy edges
- Early leaf drop
- Heat stress damage
Treatment & management
- Deep water every 2–3 weeks
- Maintain mulch
- Avoid hot exposures
Girdling Roots
Common symptoms
- One-sided decline
- Trunk constriction
- Poor canopy density
Treatment & management
- Expose root flare
- Remove girdling roots (professional)
- Long-term correction needed
When to Worry
- Sudden one-sided wilting
- Severe chlorosis with decline
- Borer holes or frass
- Heavy scale infestation
- Progressive canopy thinning
- Trunk constriction from roots
Mostly Cosmetic
- Light leaf spot
- Minor scorch
- Small scale patches
- Occasional aphids
- Early color change in drought
Notes
These issues often require professional arborist evaluation.
These are typically seasonal and resolve with proper care.
Related Resources
Related Services
When you want a professional opinion
The Root exists to help you understand your landscape. When a tree needs hands-on evaluation, a Great Western arborist can look at it in person.