Botanical Name: Alnus rugosa
Species: A. incana
Synonyms: A. incana rugosa. (Duroi.)Clausen
Common Names: Speckled Alder, Alnus incana, Grey alder
Habitat : Alnus rugosa is native to Northern and Eastern N. America – Hudson’s Bay to Virginia. Naturalized in C. Europe It grows on wet sandy or gravelly soils, usually along streams and rivers, but also in ponds and swamps. It is only found in open sunny areas, being unable to compete in dense shade.
Alnus rugosa is a deciduous small to medium size tree 15–20 m (49–66 ft) tall with smooth grey bark even in old age, its life span being a maximum of 60 to 100 years. The leaves are matte green, ovoid, 5–11 cm (2.0–4.3 in) long and 4–8 cm (1.6–3.1 in) broad. The flowers are catkins, appearing early in spring before the leaves emerge, the male catkins pendulous and 5–10 cm (2–4 in) long, the female catkins 1.5 cm (0.6 in) long and one cm broad when mature in late autumn. The seeds are small, 1–2 mm (0.04–0.08 in) long, and light brown with a narrow encircling wing. The grey alder has a shallow root system, and is marked not only by vigorous production of stump suckers, but also by root suckers, especially in the northern parts of its range. The wood resembles that of the black alder, but is somewhat paler and of little economic value.
It is in flower in May, and the seeds ripen in October. The flowers are monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and are pollinated by Wind.It can fix Nitrogen.
Suitable for: medium (loamy) and heavy (clay) soils and can grow in heavy clay and nutritionally poor soils. Suitable pH: acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist or wet soil.
Prefers a heavy soil and a damp situation. Grows well in heavy clay soils. Tolerates very infertile sites. A fast-growing but short-lived tree. Closely related to A. incana and considered to be no more than a sub-species (A. incana rugosa) by some botanists. This species has a symbiotic relationship with certain soil micro-organisms, these form nodules on the roots of the plants and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby.
Seed – best sown in a cold frame as soon as it is ripe and only just covered. Spring sown seed should also germinate successfully so long as it is not covered. The seed should germinate in the spring as the weather warms up. When large enough to handle, prick the seedlings out into individual pots. If growth is sufficient, it is possible to plant them out into their permanent positions in the summer, otherwise keep them in pots outdoors and plant them out in the spring. If you have sufficient quantity of seed, it can be sown thinly in an outdoor seed bed in the spring. The seedlings can either be planted out into their permanent positions in the autumn/winter, or they can be allowed to grow on in the seed bed for a further season before planting them. Cuttings of mature wood, taken as soon as the leaves fall in autumn, outdoors in sandy soil.
The speckled alder was quite widely used medicinally by the native North American Indians who used it to treat a variety of complaints. It is little used in modern herbalism. The bark is alterative, astringent, emetic, laxative, ophthalmic, stomachic and tonic. The bark contains salicin, which probably decomposes into salicylic acid (closely related to aspirin) in the human body. This is used as an anodyne and febrifuge. The root bark was mixed with molasses and used in the treatment of toothache. A decoction of the inner bark was used as a wash for sore eyes. The outer bark is astringent and is applied as a poultice to bleeding wounds, it also reduces swellings.
Dye; Pioneer; Soil stabilization; Wood.
This is an excellent pioneer species for re-establishing woodlands on disused farmland, difficult sites etc. Its fast rate of growth means that it quickly provides sheltered conditions to allow more permanent woodland trees to become established. In addition, bacteria on the roots fix atmospheric nitrogen – whilst this enables the tree to grow well in quite poor soils it also makes some of this nitrogen available to other plants growing nearby. Alder trees also have a heavy leaf canopy and when the leaves fall in the autumn they help to build up the humus content of the soil. Alder seedlings do not compete well in shady woodland conditions and so this species gradually dies out as the other trees become established. The tree has an extensive root system and can be planted to control banks from erosion. A dark dye is obtained from the bark. Browns, through red to orange colours can be obtained from the bark. The wood is soft, weighing 29lb per cubic foot. The tree is too small to be of importance for lumber or fuel.
Disclaimer : The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplement, it is always advisable to consult with your own health care provider.