White Poplar

(Populus alba — includes cultivars like ‘Bolleana’)

White Poplar is a fast-growing, drought-tolerant tree known for its white-backed leaves, but it is considered high-maintenance and short-lived in Colorado due to pests, disease, and aggressive suckering.

Seasonal Pest & Disease Calendar

Problem Type Active Season
Borers Insect/borer Summer
Cytospora / bacterial canker Fungus/Bacteria Spring–Fall
Leaf spot / blight Fungus Spring–Summer
Rust Fungus Summer–Fall
Aphids Insect Spring–Fall
Leaf miners Insect Spring–Summer
Suckering Physiological Spring–Fall
Environmental stress Abiotic Summer–Fall

Pest & Disease Guide (Homeowner-Friendly)

Borers

Common symptoms
  • Exit holes in bark
  • Sawdust/frass
  • Branch dieback
Treatment & management
  • Keep tree healthy
  • Avoid trunk injury
  • Professional treatments if needed

Canker Diseases

Common symptoms
  • Sunken bark
  • Oozing sap
  • Branch dieback
Treatment & management
  • Prune infected limbs
  • Improve vigor
  • No chemical cure

Leaf Spot / Blight

Common symptoms
  • Leaf spotting
  • Early leaf drop
Treatment & management
  • Remove fallen leaves
  • Improve airflow

Rust

Common symptoms
  • Orange/yellow spots
  • Leaf drop
Treatment & management
  • Usually cosmetic
  • Clean up leaves

Aphids

Common symptoms
  • Honeydew
  • Sooty mold
Treatment & management
  • Rinse foliage
  • Encourage beneficial insects

Leaf Miners

Common symptoms
  • Leaf tunneling
  • Brown trails
Treatment & management
  • Usually cosmetic
  • Remove affected leaves

Suckering

Common symptoms
  • Root sprouts spreading
  • New shoots far from tree
Treatment & management
  • Regular removal
  • Long-term solution is tree removal

Environmental Stress

Common symptoms
  • Leaf scorch
  • Early yellowing
  • Dieback
Treatment & management
  • Deep watering
  • Mulch base

When to Worry vs. When It’s Cosmetic

When to Worry (action recommended)

  • Significant borer damage
  • Expanding cankers
  • Severe leaf drop mid-season
  • Upper canopy dieback
  • Aggressive suckering spread

White Poplar is often short-lived and invasive in Colorado landscapes.

Mostly Cosmetic (monitor only)

  • Minor leaf spotting
  • Light aphid activity
  • Small amounts of leaf miner damage
  • Occasional early color change

These typically improve with watering and basic maintenance.