Arctic Willow

Plant Health Care Technician Manual

Field Reference | Training Manual | PHC Program Guide Arctic willow is a compact, fine-textured willow shrub used in mass plantings, low hedges, and borders. In Colorado it’s generally tough, but it can decline when drought-stressed or when growth is dense and airflow is poor—conditions that favor sap-feeding insects, leaf beetles, mites, and leaf spot diseases.

PLANT IDENTIFICATION (TECH CONFIRMATION)

Key identification traits

• Mature size: typically 2–4 ft tall and wide (dwarf, mounded habit)
• Leaves: narrow, willow-like leaves; blue-green to gray-green
• Stems: many thin stems from the base; good regrowth after pruning
• Site preference: full sun; best in well-drained soils (avoid chronic saturation)

Plant Identification Photos

Seasonal Pest & Disease Calendar

• Soft-bodied insects clustered on stems or leaf undersides
• Sticky honeydew (often ants present); possible sooty mold
• Leaf curl and weak, distorted new growth in heavy infestations
• Strong water spray can knock aphids off; repeat as needed
• Avoid excess nitrogen (lush growth fuels aphids)
• Insecticidal soap or horticultural oil if populations are building and distortion is increasing
• Leaf edges chewed; heavy feeding can thin the canopy
• Adults and/or larvae may be visible on foliage
• Hand-pick on small shrubs; prune out heavily infested shoots
• Encourage plant vigor (water during heat, avoid drought stress)
• Treat early if defoliation is progressing (contact insecticide per label or professional treatment)
• Fine stippling (tiny pale specks) and overall bronzing/dulling
• Leaf undersides may show mites/webbing in hot weather
• Damage is worst during hot, dry periods
• Rinse foliage—especially leaf undersides—during heat; reduce drought stress
• Miticides only if damage is spreading and populations are confirmed
• Dark brown/black spots that may have yellow halos
• Spots may merge into blotches; premature leaf drop late season
• Usually starts on lower/inner foliage where humidity stays higher
• Rake/remove fallen leaves; avoid overhead watering
• Thin lightly for airflow and faster leaf drying
• Fungicides/bactericides rarely needed for homeowners unless repeat severe defoliation occurs
• Sunken or discolored bark on stems; cracking or oozing may occur
• Progressive dieback of shoots/branches, often after stress (drought, winter injury)
• Prune out infected/dying stems several inches below visible symptoms (dispose of debris)
• Disinfect tools between cuts when dieback is active
• Correct stress drivers: improve watering, mulch, and avoid chronic crowding
• Dead tips/branches in spring; delayed or uneven leaf-out
• Worse on exposed, windy sites and during dry winters
• Desiccated buds and twig dieback most noticeable after snowmelt
• Winter watering during warm/dry spells (when soil isn’t frozen)
• Spring prune back to healthy wood once buds break

• Prune out winter dieback; thin lightly to open the canopy
• Inspect stems for aphids as buds break
• Scout for aphids on new growth and for early leaf beetle feeding
• Treat aphids only if distortion/honeydew is building
• Treat leaf beetles early if defoliation is increasing
• Monitor for spider mites during heat; look for stippling/bronzing
• Maintain even soil moisture; avoid drought stress
• Treat mites early if confirmed and spreading
• Rake/remove leaves (biggest disease reducer)
• Deep watering before soil freeze
• Remove obviously dead/cankered stems if easy to identify
• Winter watering during warm spells on dry sites
• No pesticide treatments needed

• Repeated heavy defoliation from leaf beetles (thinning year over year)
• Severe mite bronzing with premature leaf drop spreading through the planting
• Canker/dieback expanding beyond a few stems or recurring annually
• Light aphids without major distortion
• Minor late-season leaf spotting with normal fall drop
• Small amounts of tip dieback after a harsh winter (prune and recover)