Botanic Garden >> Gardening > >> Question and Answer >> Plant Species >> Conifers

Leyland Cypress Browning from Bottom: Canker Diseases

Several Leyland cypresses were turning brown from the bottom up, with healthy tops initially. The brown zone advanced upward.

The expert detailed two canker diseases: Seiridium canker (most destructive) and Botryosphaeria (Bot) canker. Both cause browning, cankers, dieback. Seiridium shows resin oozing; Bot has little resin. No resistant cultivars. Management: sanitation (prune, destroy debris, disinfect tools), mulch, irrigate during drought, remove severely damaged trees. Fungicides ineffective once infected.

Disease Comparison

Seiridium: resin flow, purple cankers, spring onset.
Bot: rust-colored branches, sunken girdling cankers, stress-triggered.
Both: prune out, improve water management, no chemical cure.

Conifers: Ash Tree Marginal Scorch: Root Stress, Not Disease; Diagnosing Lilac Decline: Root Rot and Herbicide Injury; Saving a Dying Palm Tree: Identifying and Treating Trunk Rot; Plum Tree Leaf Curl and Eggs: Beneficial vs. Pest Identification; Tulip Tree Troubles: Sapsucker Damage and Basal Decay; Pecan Tree Nut Problems: Weevils, Scab, and Spray Schedule; Kwanzan Cherry Oozing Sap: Bacterial Canker or Mechanical Injury?; Diagnosing Trunk Rot on Cold-Hardy Palms: When to Call Extension Services; Peach Tree Borer Fatality in Mature Plum Tree; Identifying and Treating Mealybugs on Bonsai

Garden Articles

Chinese Pistache with Ringed Holes and Sap: Yellow-Bellied Sapsucker Damage

Elm Tree with Peeling Bark and Defoliation: Insect Feeding Likely

Lemon Tree Leaf Curl and Yellowing in Madrid: Environmental Stress

Japanese Maple Scale Infestation: Simple WD-40 and Oil Treatment

Cedar-Quince Rust on Pear Tree: Identification and Management

Arborvitae Browning: Seiridium Canker from Stress

Mimosa Tree Diseases: Focus on Fusarium Wilt

Plants

Pine Tree Yellowing Needles and White Sudsy Substance: Insect Identification

Single Quaking Aspen Declining: Check for Root Pests or Cytospora Canker

Peach Leaf Curl on Fruit Salad Tree: Diagnosis and Prevention

Grapefruit Tree Greasy Spot Fungus: Organic Treatment Option

Black Knot Disease on Plum: Pruning and Fungicide Protocol

Persimmon Scale Infestation: Waxy Protrusions with Discharge

Holly Sooty Mold and Leaf Drop: Insect-Driven Dual Symptom