Tree & Shrub Planting and Care in Seattle, WA

Quick answer

Healthy trees and shrubs in the Seattle area start with planting at the right depth in a wide, shallow hole, mulching away from the trunk, and watering through the first two dry summers. Fall is the best planting season. Seattle and many nearby cities regulate removal of larger trees, so check before cutting.

Last updated October 22, 2026

Big trees define the Seattle area: Douglas fir, western redcedar, bigleaf maple and madrone, along with decades of planted ornamentals. Trees and shrubs are the long-term structure of a landscape, and in this region they also hold slopes together and soak up winter rain. Planting them right and pruning them thoughtfully pays off for decades, and some cities regulate what you can remove.

Planting it right

Set the root flare at or slightly above grade. Planting too deep is a leading cause of slow decline.
Dig wide, not deep. On glacial till, a deep hole in dense soil can fill with water like a bucket in winter. A wide, shallow hole, or planting slightly high in a mound, helps.
Loosen circling roots on container plants.
Mulch a few inches deep, pulled back from trunks.
Water through the first two dry summers. Even natives need help until roots are established.

Best time to plant

Fall is generally the best planting season in western Washington. Roots grow in the mild, moist winter, and plants are better prepared for the summer drought that follows. Early spring is the second choice.

Pruning basics

Remove dead, damaged and crossing branches first.
Prune spring-flowering shrubs, such as rhododendrons and azaleas, soon after they bloom.
Avoid shearing every shrub into a ball; it thins the interior and reduces flowering.
Never top trees. Topping creates weak, fast regrowth and decay, and in some cities it can count as removal under tree rules.
Thinning dense canopy, done properly, can let more light reach a struggling lawn or bed.

Tree rules in Seattle and nearby cities

Seattle regulates trees on private property through SDCI's tree protection code, which was updated in recent years. Depending on tree size, species and whether development is involved, removal may require SDCI review, replacement trees and public notice, and the work generally has to be done by a tree service provider on the city's registry. Trees in the planting strip are street trees and need an SDOT permit before removal. Bellevue, Kirkland, Redmond, Sammamish and other cities have their own tree retention rules. On mapped steep slopes, tree and vegetation removal is restricted further. Check with your city before removing or heavily pruning any sizable tree.

Invasive plants

English ivy climbing trees, Himalayan blackberry thickets, English holly and knotweed are common problems around Seattle. King County lists several of these as noxious weeds, with some, such as knotweed, subject to control requirements in certain situations. Removing ivy from tree trunks and replacing blackberry with natives are common landscape projects. The King County Noxious Weed Program offers species-specific guidance.

Large trees and removals

Landscaping companies commonly plant trees and maintain shrubs and small ornamentals. Large tree pruning, removals and work near power lines belong with a tree service that carries the right equipment and insurance, ideally with an ISA Certified Arborist. Washington's contractor rules list tree removal as its own specialty, so ask what a company is registered for.

Watch for common problems

Root rot on shrubs planted in soggy, poorly drained spots
Summer drought stress on new plantings and shallow-rooted trees
Leaf spots and fungal problems on crowded, damp plantings

WSU Extension Master Gardener clinics in King, Pierce and Snohomish counties can help identify plant problems. When you're ready, request a landscaping company for planting or shrub care.

Frequently asked questions

Do I need a permit to remove a tree in Seattle?

Possibly. SDCI regulates trees on private property, and depending on size, species and circumstances, removal may need review, replacement and notice, with work done by a registered tree service provider. Street trees need an SDOT permit. Check with SDCI first.

When should I prune rhododendrons?

Rhododendrons and azaleas set next year's flower buds after blooming, so prune them soon after the flowers fade. Pruning later can remove next spring's blooms.

How do I deal with English ivy on my trees?

Cutting ivy stems at the base of the trunk and pulling it back from the trunk lets the upper vines die. King County's noxious weed program publishes best management practices for ivy and other invasives.

Sources and further reading

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