Winter Planting & Plant Care Best Practices in Western Washington

A short Guide for Landscapers, Contractors, and Plant Nurseries

 

At MB Nursery, we understand that successful winter projects lead to stronger landscapes and stronger partnerships, come spring. Our goal is to support landscapers, contractors, and garden centers with plant material that’s well-prepared for Pacific Northwest winters, along with practical guidance grounded in real-world growing conditions. From winter-hardened inventory and careful crop management to ongoing planning for spring availability, we approach the season with the same long-term mindset our customers bring to their projects. When your installations thrive, your schedules stay on track, and your clients are satisfied, we succeed alongside you—season after season.

 

Winter in Western Washington looks very different from winter in most parts of the country. While temperatures are generally mild, extended rainfall, saturated soils, intermittent freeze events, and limited daylight create unique challenges—and opportunities—for landscape professionals.

Understanding how plants respond to these conditions helps reduce winter losses, improve spring performance, and support long-term plant health. Below are winter planting and care best practices specifically tailored to the Pacific Northwest.

 

Understanding Winter Conditions in the Pacific Northwest

 

Western Washington winters are defined less by extreme cold and more by persistent moisture and reduced soil oxygen. Common challenges include:

• Prolonged periods of saturated soil

• Increased risk of root rot and soil compaction

• Occasional freeze events following mild, wet weather

• Reduced photosynthesis due to short daylight hours

 

At the same time, many woody plants are dormant, making winter an effective season for selective planting, structural pruning, site corrections, and planning.

 

Winter Planting: What Works Best

 

Plants Suitable for Winter Planting:

Winter planting can be successful when soils are workable and well-drained. Installing plants during dormancy allows roots to establish gradually before spring growth begins.

Good winter planting candidates include:

• Bare-root and container-grown deciduous trees
  (Maple, birch, serviceberry)

• Hardy evergreen shrubs
  (Rhododendron, euonymus, boxwood)

• Pacific Northwest native plants
  (Vine maple, red twig dogwood, sword fern)

Best practices:

• Avoid planting during freeze events

• Confirm adequate drainage before installation

• Minimize soil compaction during planting

 

Plants to Avoid Planting in Winter

Some plants struggle in extended wet conditions or establish poorly during winter dormancy.

Avoid winter planting of:

• Plants that prefer dry winter conditions
  (Lavender, rosemary, flax)

• Cold-sensitive or marginally hardy species
  (Rhaphiolepis, escallonia, hebe, choisya, loropetalum)

• Frost-tender or newly introduced subtropicals

• Any plants installed in poorly drained or waterlogged soils

When soils are saturated, delaying installation is often more cost-effective than replacing failed plants.

 

Winter Pruning: Timing Matters

Winter pruning can be highly beneficial—but only for the right plants.

 

Plants That Can Be Pruned in Winter

• Deciduous trees (fully dormant), including Japanese maples

• Fruit trees for structure, airflow, and disease reduction

• Shrubs that bloom on new wood

• Structural and corrective pruning

 

Dormant-season pruning improves branch visibility and reduces disease pressure.

 

Plants to Avoid Pruning in Winter

Do not prune the following during winter months:

• Rhododendrons and azaleas (flower buds already set)

• Thuja (arborvitae), due to winter burn risk

• Nandina, which provides winter interest

• Rhaphiolepis (Indian hawthorn), prone to cold damage

• Spring-flowering shrubs

• Conifers and needle evergreens

• Broadleaf evergreens

For spring-blooming plants, prune after flowering.

 

Winter Fertilization: Less Is More

 

Why Winter Fertilizing Is Discouraged

• Plants are dormant and not actively absorbing nutrients

• Nutrients readily leach from saturated soils

• Fertilization can stimulate tender growth vulnerable to frost

 

When Fertilization May Be Appropriate

• Late winter (February–March)

• Only with slow-release fertilizers

• Based on soil test results

• For evergreen plants showing nutrient deficiencies

 

In most cases, fertilization is best reserved for early spring.

Managing Wet Soils and Freeze Events

Drainage and Soil Protection

Prolonged rainfall increases the risk of root damage and soil compaction.

 

Best practices include:

• Limiting foot and equipment traffic on wet soils

• Avoiding unnecessary grading during winter

• Incorporating organic matter where appropriate

• Using raised beds or berms in poorly drained areas

 

Protecting Plants During Cold Snaps

 

Even cold-hardy plants can suffer damage during sudden freezes.

Protective measures include:

• Applying 2–3 inches of mulch to root zones (keep away from trunks)

• Watering prior to hard freezes if soils are dry

• Covering sensitive plants with frost cloth during extreme cold

 

Plants That Provide Winter Color and Interest

Winter landscapes don’t have to look dormant. Many plants provide color, structure, and fragrance during the colder months.

Popular winter and early-spring interest plants in the PNW include:

• Hellebores

• Camellias

• Mahonia

• Winter heath (Erica)

• Witch hazel (Hamamelis)

• Sarcococca

• Viburnum tinus

• Daphne odora

• Red flowering currant (early spring)

 

Evergreen trees and shrubs—both coniferous and broadleaf—remain essential for year-round structure and visual interest.

 

Using Winter to Prepare for Spring

Winter is an ideal time to:

• Evaluate plant performance from the previous season

• Identify drainage, soil, or siting issues

• Plan plant replacements and new installations

• Schedule spring pruning and fertilization

• Educate clients on seasonal expectations

 

Addressing site and structural issues during winter helps landscapes transition smoothly into spring growth and reduces reactive maintenance later in the season.