The Dee Runk Boxwood (Buxus sempervirens ‘Dee Runk’) is a popular evergreen shrub, valued for its upright, columnar growth and glossy green foliage. It is often used in landscaping for hedges, accents, or as a specimen plant, providing year-round structure. Adaptable to various sun and shade conditions, this resilient cultivar can still face health and appearance issues.
Identifying Common Dee Runk Boxwood Problems
Diagnosing Dee Runk Boxwood problems involves observing specific changes.
Pests
Boxwood leafminer activity causes blisters, tunneling, or blotchy discoloration on leaves. Boxwood psyllids lead to cupped or distorted leaves and a white, waxy residue. Spider mites cause fine stippling, leading to a bronzed or dusty appearance.
Diseases
Volutella blight causes branches to die back, with leaves turning reddish-brown and possibly exhibiting pinkish spore masses. Macrophoma leaf spot appears as small black dots on dead or stressed leaf areas. Boxwood Blight can cause dark brown to black leaf spots, rapid defoliation, and distinctive black streaks or cankers on stems. Root rot leads to general wilting, yellowing foliage, and overall decline.
Environmental Stressors
Winter burn results in foliage turning a yellow-orange to reddish-brown, particularly on exposed areas. Nutrient deficiencies often cause general yellowing of leaves. Drought stress includes wilting or drooping foliage, while overwatering can also lead to wilting and yellowing.
Addressing Pest Issues
Once pests are identified, specific treatments can manage their populations and reduce plant damage.
For boxwood leafminers, pruning affected leaves and stems helps reduce infestation. Early season applications of systemic insecticides or horticultural oils can target larvae.
Boxwood psyllids can be managed with strong water sprays to dislodge them. Insecticidal soaps or neem oil are also effective. Apply treatments thoroughly, ensuring coverage.
Spider mites can be controlled with repeated applications of insecticidal soap or horticultural oil. Good plant hydration makes plants less susceptible. Always follow product label instructions for proper application and safety.
Managing Disease Problems
Managing Dee Runk Boxwood diseases involves cultural practices and targeted treatments.
For Volutella blight, promptly prune all affected branches into healthy wood. Remove and dispose of fallen leaves and plant debris to reduce fungal spores. Improving air circulation by light thinning deters disease.
Macrophoma leaf spot is an opportunistic fungus affecting stressed plants. Pruning affected portions is usually sufficient; focusing on overall plant health helps prevent its occurrence.
If Boxwood Blight symptoms appear, promptly remove and dispose of diseased leaves and stems, preferably bagged for landfill to prevent fungal persistence. Sanitize pruning tools with bleach or alcohol between cuts and plants to prevent spread. Fungicide applications containing active ingredients like chlorothalonil can be used preventatively in areas with known blight or during conducive periods.
Resolving Environmental and Cultural Stress
Adjustments in care can promote recovery from environmental and cultural stresses impacting Dee Runk Boxwood health.
Winter burn can be mitigated by adequate watering before winter freezes and physical protection like burlap wraps in exposed locations. Prune damaged branches back to healthy wood in late winter or early spring.
Root rot, often from overwatering or poorly drained soil, requires improved drainage and adjusted watering. Dee Runk Boxwood needs well-drained soil and does not tolerate “wet feet.” Ensure planting sites are not low-lying or collect water, and for container plants, confirm adequate drainage holes. Allow the soil to dry out to a depth of about five inches before watering again.
Nutrient deficiencies can be identified through a soil test. Based on results, apply an appropriate balanced fertilizer or one specific to the deficient nutrient. Fertilization should be done carefully, as Dee Runk Boxwood has shallow roots.
Drought stress necessitates deep and thorough watering. While established Dee Runk Boxwoods can tolerate some drought, consistent watering during dry spells is important, especially for young plants. Ensure water reaches the entire root zone, and consider mulching to retain soil moisture.
Preventative Care for Healthy Boxwoods
Proactive measures contribute to the long-term health of Dee Runk Boxwoods.
Proper planting is foundational: select a site with well-drained soil. Provide some afternoon shade in hot climates to prevent leaf scorch. Plant the boxwood with the root ball slightly above the soil line, and apply a layer of organic mulch to conserve moisture and regulate soil temperature.
Water consistently, especially during the establishment period and dry spells. Water deeply, allowing the soil to dry somewhat between waterings. Avoid overhead watering in late afternoon or evening, as wet foliage can encourage fungal diseases.
Fertilization should be guided by soil test results. An early spring application of a balanced fertilizer can support growth.
Regular, light pruning in late winter or early spring maintains the desired shape and encourages density. Thinning the plant’s interior can improve air circulation and light penetration, which helps deter fungal problems.
Maintaining garden sanitation by raking and removing fallen leaves and debris reduces potential disease inoculum.