Herbs & Plants

Alnus rubra

[amazon_link asins=’B00MN2L1TW,B00RKHN8I2,B072LPT3GC,B072L11VL6,1508502285,B071LRJ8XX’ template=’ProductCarousel’ store=’finmeacur-20′ marketplace=’US’ link_id=’d3ed935c-895f-11e7-a380-d9bc78e52b19′]

Botanical Name : Alnus rubra
Family: Betulaceae
Genus: Alnus
Subgenus: Alnus
Species: A. rubra
Kingdom: Plantae
Order: Fagales

Synonyms :Alnus oregona.

Common Names : Red Alder, Oregon Alder

Habitat :Alnus rubra is native to Western N. America – Alaska to California. It grows on moist rich soils in woods, usually below 600 metres and within 50 km of the coast.

Alnus rubra is the largest species of deciduous alder tree in North America and one of the largest in the world, reaching heights of 20 to 30 m (66 to 98 ft). The official tallest red alder (1979) stands 32 m (105 ft) tall in Clatsop County, Oregon (USA). The name derives from the bright rusty red color that develops in bruised or scraped bark. The bark is mottled, ashy-gray and smooth, often draped with moss. The leaves are ovate, 7 to 15 centimetres (2.8 to 5.9 in) long, with bluntly serrated edges and a distinct point at the end; the leaf margin is revolute, the very edge being curled under, a diagnostic character which distinguishes it from all other alders. The leaves turn yellow in the autumn before falling. The male flowers are dangling reddish catkins 10 to 15 cm (3.9 to 5.9 in) long in early spring, and female flowers are erect catkins which develop into small, woody, superficially cone-like oval dry fruit 2 to 3 cm (0.79 to 1.18 in) long. The seeds develop between the woody bracts of the ‘cones’ they are shed in the autumn and winter
It is in flower in March, and the seeds ripen from Sep to 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. The plant can tolerate maritime exposure.
Prefers a heavy soil and a damp situation. Grows well in heavy clay soils. Tolerates very infertile sites. A very wind resistant tree with excellent establishment in severely exposed sites, it tolerates severe maritime exposure. The red alder is a very fast growing tree, even when planted in severe exposure, but it is short-lived, dying when 60 – 80 years old. Trees that are 5 years old from seed have reached 6 metres in height on a very exposed site in Cornwall, they are showing no signs of wind-shaping. This is an important pioneer tree, quickly invading logged or burnt over sites, and providing ideal conditions for other trees to become established. A very ornamental tree. 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. Red alder has been estimated to fix as much as 300 kg of nitrogen per hectare. Special Features: Attracts birds, North American native, Inconspicuous flowers or blooms.

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.
Edible Uses:
Catkins – raw or cooked. They are rich in protein but have a bitter flavour and are not very palatable. Inner bark – cooked, It must be dried since it is emetic when fresh. No more details are given but inner bark is often dried, ground into a powder and then used as a thickening in soups etc or mixed with cereals when making bread. Sap – raw. Harvested in late winter, the flow is best on a warm, sunny day that follows a cold frosty night. A sweet flavour, it was often used to sweeten other foods. Buds.
Medicinal Uses:
Red alder was widely employed medicinally by native North American Indians who mainly used the bark to treat a wide range of complaints. The plant is little used in modern herbalism. The bark is appetizer, astringent, cathartic, cytostatic, emetic, 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. An infusion of the bark has been used in the treatment of many complaints such as headaches, rheumatic pains, internal injuries and diarrhoea. Externally, a poultice of the bark has been applied to eczema, sores and aches. The sap is applied externally to cuts. The catkins and young cones are astringent and have been chewed in the treatment of diarrhoea.

Other Uses:
Charcoal; Dye; Fuel; Hedge; Pioneer; Shelterbelt; Soil stabilization; Tannin; Wood.

A fast-growing and very wind resistant tree, it is an excellent plant for providing rapidly produced shelterbelts. The trees extensive root system also makes it suitable for controlling erosion along the banks of rivers. 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. Tannin is obtained from the bark and the strobils. Both the roots and the young shoots have been used in making baskets. A red to brown dye is obtained from the bark. Wood – soft, brittle, not strong, light, close and straight-grained, very durable in water. An important lumber tree, it makes a good imitation mahogany and is used for cheap furniture etc. A good fuel, it does not spark so can be used in the open, it also makes a high grade charcoal.

Landscape Uses:Border, Erosion control,  Woodland garden.

Known Hazards : The freshly harvested inner bark is emetic but is alright once it has been dried.
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.


Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.