Speckled Alder trees (Alnus rugosa syn. Alnus incana)

Common Name: Speckled Alder

Speckled alder is a cold hardy, native shrub. It is often planted on infertile sites so it can fix nitrogen deficient soils.

Scientific Name: 
Family: Betulaceae
Genus: Alnus
Species: A. incana

Hardiness Zone: 2 to 6
Height: 15 to 25 ft
Width: 15 to 25 ft

 Common characteristics:

Speckled alder is most often seen in a multi-trunked form with a broad-rounded irregular crown. The bark of these trees is brown to reddish-brown to grayish, with scattered white lenticels. Older bark is grayish to reddish-brown with pale horizontal lenticels. Leaves are alternate, simple, and egg-shaped with acuminate tips. The edges are coarsely doubly toothed with shallow lobes. The upper surface of leaves is dark green while the lower surface is dull green and hairy, especially along the veins. The speckled alder is monoecious meaning male and female flowers are borne separately on the same plant. They are formed in clusters called catkins, blooming in very early spring before leaves emerge. It flowers in May and the seeds open and ripen in October.

Where it grows:

Grows well in moist, well-drained soils. Will tolerate wet sites that experience occasional flooding. Best in full sun to partial shade. 

How it’s used:

The Speckled Alder Tree (Alnus rugosa) is a deciduous tree that has been widely used throughout history for its medicinal purposes as well as in modern herbalism. This is an excellent pioneer species for re-establishing woodlands or difficult sites.

Speckled Alder is a fast-growing and flood-tolerant species that lives, approximately 40-50 years. It can be thicket-forming and provides erosion control along watercourses in the mountains. Alders' fixes nitrogen deficient soils and thus serve as nutrient-giving plant. It can be used in the urban setting in residential or park settings and under powerlines. 

Where it is native to:

Speckled alder trees (Alnus rugosa syn. Alnus incana) are native to central and eastern Canada

Speckled Alder Information

Speckled alder trees growing in the wild look a lot like shrubs. Speckled alder trees do not get above 25 feet (7.5 m.) tall and can be much shorter in colder climates. In addition, speckled alder trees usually grow with multiple slender stems like bushes. The common name comes from the fact that the stems, heavily lined with horizontally borne lenticels, appear speckled.

Both male and female alder flowers are called catkins. The males are long and conspicuous, while female flowers are reddish and smaller, and lack outer scales.

How to Grow a Speckled Alder

Sowing seeds

Four weeks prior to sowing, soak seeds in cold water for 24-48 hours. The seeds should then be surface dried. Mix the seeds with a little moist horticultural sand and place in loosely tied plastic bags in the bottom of a fridge (not the freezer!). Four weeks at low temperatures improves the speed and evenness of germination.

Alder grows very fast provided plenty of moisture is available to them. Aim to sow during April on seedbeds or in a pot (around 5 seeds per pot and remove all but the strongest seedling).

Cover the seed thinly (3-5mm of coarse horticultural sand or grit). It is important that the seed is not covered too thickly as this could prevent germination. Firm the seeds gently.

Never let alder seeds or young seedlings dry out! These are trees that grow on damp ground and drying out can very quickly lead to the death of many plants. If planting in pots, stand pots in a shady, sheltered spot outside and water, from the top, until the seedlings emerge. Keep moist at all times.

Growing

Alder should germinate rapidly. Alder can produce its own nitrogen (the element essential for strong growth). Added feeding for alder seedlings will benefit even more from a small application of fertilizer when they are about six weeks old.

It would not be unreasonable to expect up to 60cm growth in the first year, but the plants can be transplanted or left in the pots (repotting if necessary) for another year. Plants in pots will need to be fed regularly while they are actively growing (April-September).

When your alder is tall enough, it can be planted into its new home. Prepare the site well by clearing away any weeds or grass and make a hole big enough to accommodate the root ball. Plant carefully in the hole, to the same depth as it was in the pot, and firm back the soil.

Be sure the ground is wet and that the trees get full sun to part sun. If that’s the case, care of speckled alder should be easy. If you want to grow the alder to look more like a tree than a shrub, you can prune out the stems, leaving only the strongest to serve as the trunk.

Medicinal Uses 

The speckled alder was quite widely used medicinally by the native North American Indians who used it to treat a variety of complaints. The bark is alterative, astringent, emetic, laxative, ophthalmic, stomachic and tonic.

Note: It is up to the buyer to verify nutritional and health benefits with a qualified professional for all edible plants listed.

Seeds are fresh, untreated, open-pollinated for seed saving, and organic.

You will receive a package of 100 seeds. 

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Due to the nature of our products, seed germination rates may vary depending on storage and growth conditions. Some varieties have a naturally low germination rate, at around 50%. When a variety has a lower germination rate, it is usually indicated on the packet and we endeavor to provide more seeds to compensate. The vast majority of our seeds have germination rates of over 85%. We work hard to provide you with the best service possible.