Tree Pests & Diseases
Hawthorn Tree Maintenance
Hawthorns are tough ornamental trees with flowers, fruit, and strong wildlife value, but they can develop rust, leaf spot, fire blight, aphids, and scale in Colorado landscapes.
- Species
- Hawthorn Tree
- Botanical Name
- Crataegus spp.
- Group
- Ornamental Trees
- Tracked Problems
- 7
Seasonal Calendar
| Problem | Type | Active Season |
|---|---|---|
| Fire blight | Bacteria | Spring–Summer |
| Cedar-hawthorn rust | Fungus | Spring–Summer |
| Leaf spot | Fungus | Spring–Summer |
| Scale insects | Insect/scale | Spring crawlers; visible year-round |
| Aphids | Insect | Spring–Fall |
| Spider mites | Mite | Summer |
| Environmental stress | Abiotic | Summer–Fall |
Pest & Disease Guide
Fire Blight
Common symptoms
- Blackened shoots
- Crook-shaped tips
Treatment & management
- Prune infected branches
- Sanitize tools
Cedar-Hawthorn Rust
Common symptoms
- Orange leaf spots
- Fruit spotting
Treatment & management
- Reduce nearby juniper sources
- Treat severe cases
Leaf Spot
Common symptoms
- Leaf lesions
- Early drop
Treatment & management
- Clean up leaves
- Improve airflow
Scale Insects
Common symptoms
- Bumps on stems
- Thinning foliage
Treatment & management
- Horticultural oil
- Treat crawler stage
Aphids
Common symptoms
- Sticky honeydew
- Leaf curling
Treatment & management
- Rinse foliage
- Encourage predators
Spider Mites
Common symptoms
- Bronzed foliage
- Fine stippling
Treatment & management
- Increase irrigation
- Rinse canopy
Environmental Stress
Common symptoms
- Scorch
- Poor vigor
Treatment & management
- Deep watering
- Mulch base
When to Worry
- Repeated fire blight
- Heavy rust infection
- Branch dieback
Mostly Cosmetic
- Minor leaf spotting
- Light aphids
- Some summer scorch
Notes
These can affect flowering, fruit, and long-term structure.
These often improve with pruning and irrigation.
Related Resources
Related Services
Great Western Tree Care
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.