Colorado cedar trees, such as Rocky Mountain juniper and Eastern red cedar, are known for their hardiness, drought tolerance, and striking characteristics like silvery-blue foliage and aromatic wood. While not considered “true” cedars, these trees are beloved by Colorado residents for their ruggedness and ecological benefits.
Eastern red cedars and Rocky Mountain junipers are highly susceptible to several specific fungal diseases. Knowing how to identify these Colorado cedar tree diseases and treat them can help to avoid severe damage.
Common Colorado Cedar Tree Diseases
Rocky Mountain junipers and Eastern red cedars are susceptible to the same diseases. They include:
- Cedar-Apple Rust & Juniper-Hawthorn Rust – Rust diseases require at least two alternate hosts to complete their life cycle. One part of the lifecycle occurs on cedars and junipers, while the other part takes place on apples, pears, and hawthorns. Galls form on cedars and junipers in the spring during wet weather. The galls are obvious – orange and gooey with tentacle-like structures coming out of them. Rust diseases are mainly an aesthetic issue on cedars and junipers, though they can sometimes cause branch dieback.
- Phomopsis Tip Blight – This fungal disease appears in cool, wet spring conditions and mostly affects young trees. It spreads through infected plant debris and in water droplets from rain or overhead irrigation. Phomopsis tip blight kills new shoot tips. The affected tips turn brown and die back from the tip inward. Symptoms occur during the summer.
- Kabatina Tip Blight – Kabatina tip blight has similar symptoms to Phomopsis, but symptoms appear in late winter to early spring. Symptoms appear on the previous season’s growth. Tracking the onset of symptoms between Phomopsis and Kabatina helps determine treatment timing.
- Canker Diseases – Fungal canker diseases enter through wounds or stressed tissue. They cause sunken, discolored cankers on branches and stems, can girdle branches, and lead to dieback. They are most problematic on drought-stressed trees.
Homeowners often misdiagnose canker diseases as pest activity. An accurate diagnosis from a certified arborist can help differentiate between the two and determine treatment options.
Signs Your Cedar Tree May Be Diseased
Signs of Colorado cedar tree diseases are very similar for Eastern red cedars and Rocky Mountain junipers. While every disease has its unique set of symptoms, here are some general signs your tree could be infected:
- Browning branch tips
- Unusual discoloration
- Early needle drop
- Galls on branches
- Cankers on branches and stems
What Causes Colorado Cedar Tree Diseases?
Colorado’s generally dry climate suppresses many fungal diseases, but late-spring moisture, overhead irrigation, and drought stress create conditions where diseases can establish and spread.
The state is known for its unpredictable spring weather patterns. The climate can swing from mild, sunny days in the 60s and 70s to heavy, wet snowfall within the same week. This instability can heighten disease pressure.
Treatment Options for Colorado Cedar Tree Diseases
Treating diseases infecting Rocky Mountain juniper and Eastern red cedar trees depends on correctly identifying the fungal disease affecting your tree.
- Cedar-Apple Rust & Juniper-Hawthorn Rust – Prune galls and dispose of the infected clippings to stop the spread.
- Phomopsis & Kabatina Tip Blight – Identify which tip blight is infecting your tree to determine the timing of treatment. Once identified, prune blighted branches 4 to 6 inches below the visibly diseased area, disinfecting your pruning shears between each cut. Consult with an arborist about applying fungicide in early spring for Phomopsis and in fall for Kabatina.
- Canker Diseases – Remove affected branches or twigs by cutting several inches below the canker, disinfecting shears between each cut. Once removed, bag, and trash diseased branches. Avoid composting the trimmings as the spores from cankers can survive the composting process.
When to Call a Professional
Certified arborists have a deep understanding of tree and shrub health. They can safely and effectively identify and treat diseases to ensure your property remains beautiful and healthy.
Arborists accurately identify harmful fungal diseases and use advanced methods to treat them, helping to protect healthy foliage in your yard.
CONTACT DAVEY TODAY FOR YOUR TREE INSPECTIONS
FAQ: How Can I Tell if My Cedar Has A Disease?
Yes. Rusts require two alternating tree hosts to spread: a cedar/juniper tree and a tree in the rose family, like crabapples, pears, apples, and hawthorns.
Orange growths are signs of rust fungus that can cause aesthetic damage and branch dieback.
Browning branch tips can be a sign your tree is infected with a disease. If you notice the tips of your trees turning brown, contact a certified arborist for an inspection.
Seasonal browning happens in late summer through fall on older, interior needles, while diseased browning appears on outer growth, new tips, or sometimes entire branches.
