Species Sitka Alder
green foliage with brown branches with light-brown flowers

Sitka Alder

Alnus alnobetula subsp. sinuata

Sitka Alder (Alnus alnobetula subsp. sinuata) is a deciduous flowering shrub found in the Pacific Northwest region of the U.S. and around Alaska's Aleutian Islands. It is a fast grower, reaching up to 10-15 feet in height and its trunk can be up to two feet in diameter. Its bark is light gray and may be rough or smooth. Its leaves are oval-shaped and its flowers are yellow. The shrub produces a seed that is an important food source for many birds. It is a hardy and drought-resistant species that prefers wetter sites. It prefers full sun but can also tolerate partial shade. Its root system helps reduce erosion and increase water infiltration. Sitka Alder can also be used for erosion control, fuel, and can provide a source of nitrogen for adjacent plants.

Watering:

Frequent

Propagation:

Cutting,Grafting Propagation,Layering Propagation,Seed Propagation,Root Cutting

Hardiness Zone:

Flowers:

Yellow Flowers

Sun:

Sun, Partial Shade, Shade

Soil:

Sand, Loam

Cones:

Yes

Leaf:

Yes

Leaf Color:

green

Growth Rate:

Low

Drought Tolerant:

Yes

Salt Tolerant:

Yes

Care Level:

Moderate

watering

Sitka Alder requires moderate but consistent watering during its active growing season (typically spring to fall). The soil for Sitka Alder should remain moist, but not overly wet. During very hot summer days, it is best to water the plant twice daily; in the morning and the late afternoon. During cooler periods, about once every 3-5 days should be enough. Sitka Alder should not be allowed to sit in soggy soil, and it may require additional drainage to prevent waterlogging.

sunlight

Sitka Alder (Alnus alnobetula subsp. sinuata) needs an adequate amount of sunlight for growth and maintenance. This species does not require full sun, but prefers light, dappled shade. Sitka Alder benefits from at least 4 hours of direct sun each day, but can tolerate full sun in the morning or late afternoon with some mid-day shade. During the hotter months of summer, especially in the southern US, adequate shade should be provided in order to prevent leaf-scorching and enhance overall health.

pruning

Sitka Alder should be pruned during late winter or early spring, before new buds appear. This species should not be severely pruned, but light trimming can be done to keep its natural shape and growth. Trimming should involve the removal of dead or damaged branches back to a healthy bud. To maintain its natural shape and size, light pruning should be done annually and serious pruning should be done every 3 to 5 years. When pruning, it's important to make sure the cuts are less than 25% of the plant's canopy eachyear to avoid stressing the plant. Lastly, no cutting of the main trunk should ever be done.

Season

Fall
Winter
Spring
Summer
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Starts Flowering

Sitka Alder typically starts flowering in April.