Coast Spruce Picea sitchensis

Sitka spruce is a large, coniferous, needled evergreen tree that can grow from 40 to 230 feet tall. It can grow to have a trunk diameter of 16 to 22 feet. Reportedly, it is the largest species of spruce, the third tallest conifer species in the world, and the fourth largest conifer. The Giant Sequoia, Coast Redwood, and Western Red Cedar are the only conifers that exceed it in size. The Sitka Spruce has an open crown and pendulous branches that can reach the ground. It has 1-inch long, stiff, four-sided, blue-green needles with very sharp tips. Each needle arises from a raised woody peg or sterigma. The bark is smooth and gray but becomes purplish-brown and scaly as the tree matures. Male and female cones appear from early April to early June. The fruit is a mature woody cone that is found near the top of the tree in late summer and fall. The Sitka Spruce is a member of the Pinaceae or pine family. 

This tree is native to the Pacific Coast from Alaska to California, and it is the State Tree of Alaska. It is typically found along moist cool coasts of the Pacific Northwest and performs best in moist foggy rainforests. They are rarely more than 10 miles from the ocean.  

The genus name, Picea, is thought to be derived from the Latin word pix which means "pitch." This refers to the sticky resin in the bark of the tree. The species name, sitchensis, references Sitka, Alaska. Sitka is the name of a tribe of Native Americans that inhabit the coasts of southeast Alaska and British Columbia.

This tree prefers full sun to partial shade. It performs best in cool and moist coastal climates and moist to wet soils with a high organic matter content. This species is more wind and salt spray tolerant than other similar trees. They are propagated by seeds, but cuttings and layering are other options. The tree will begin to produce cones when they are 15 to 40 years old. 

Sitka spruce is a valuable food source and nesting and roosting site for many birds and small mammals. Many of these trees are found in Olympic National Park, Vancouver Island, and Oregon Coast. Some specimens are over 1300 years old.

The Sitka spruce requires cool and moist climates near the ocean. Based on the size of the tree, it has very limited use in most landscapes.

Season of Interest:

Bark:  Year-round     Bloom:  Spring       Foliage:  Year-round    Fruit:  Summer and Fall       

Quick ID Hints:

• large, tall, coniferous, needled-evergreen tree
• pendulous branches
• smooth, thin, gray bark that becomes dark purplish-brown and scaly
• stiff, flat, four-sided, 1-inch-long needles, spirally arranged bluish-green upper surface and bluish-white on the undersides with very sharp tips 
• each needle is formed on a woody peg or sterigma
• male cones and female cones are produced from late April to early June
• male cones are up to 5/8 inches long and red; female cones are 2 to 3 inches long, reddish-brown, and found near the top of the tree
• Woody seed cones mature in late August through September and seeds may be harvested in October

Insects, Diseases, and Other Plant Problems:  The Sitka spruce is susceptible to the green spruce aphid. It was reported that this aphid caused high mortality of this particular species in the States of Washington, Oregon, and California in 2020. The tree is also vulnerable to the white pine weevil, ambrosia beetle, spruce beetle, scales, adelgids, and spider mites. Galls are caused by the Cooley spruce gall adelgid and are frequently seen. Other potential problems include fungal diseases resulting in root and stem rots. The tree is also vulnerable to windthrow during severe storms.

VIDEO created by Ryan Contreras for “Landscape Plant Materials I:  Deciduous Hardwoods and Conifers or Landscape Plant Materials II:  Spring Flowering Trees and Shrubs” a plant identification course offered by the Department of Horticulture at Oregon State University