Alnus incana
ssp. rugosa
Speckled Alder or Hazel Alder
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An ordinary tree rarely seen in the cultivated landscape that is one of the first to flower in the spring.
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Family |
Betulaceae |
Genus |
Alnus |
Species |
incana |
Category |
Woody |
Type |
Tree (deciduous), Shrub (deciduous) |
Subspecies |
rugosa |
Synonyms |
Alnus rugosa |
USDA Hardiness Zone |
2 - 6 |
Canadian Hardiness Zone |
0a - 6a |
RHS Hardiness Zone |
H7 - H6 |
Temperature (°C) |
(-45) - (-18) |
Temperature (°F) |
(-43) - 0 |
Height |
5-8 m |
Spread |
5-8 m |
General Description |
A fast growing tree, typically multi-trunked, wrinkled green-grey leaves with little to no autumn colour. This species has been placed on the IUCN Red List as least concern. |
Landscape |
It has limited use in the landscape as it is not an ornamentally significant species. It does find use in land reclamation since its roots have the ability to fix nitrogen and thus it is tolerant of very poor soils. Its seed are consumed by a wide variety of birds species while some species of butterfly larvae are known to feed on the leaves thus it may be used to attract wildlife to the landscape. |
Cultivation |
Grow in acidic, moist soils. |
Growth |
Fast |
ID Characteristic |
Bark with pronounced lenticels presenting a speckled appearance, dull green wrinkled leaves with furrowed veins and red hairs on the underside. |
Pests |
Diseases can include canker, which can be severe, leaf curl and powdery mildew. Insect pests may include flea beetles, lace bugs, tent caterpillars, leaf miners and aphids. On alkaline soils chlorosis will occur. |
Habitat |
Marshlands, coastland and riverbanks. |
Bark/Stem Description |
Often multi-stemmed with reddish-brown bark covered in grey, pronounced lenticels. |
Leaf Description |
The leaves are 5-10 cm long, with significantly wrinkled surfaces, dull green in colour, wedge-shaped at the base with an acute apex, doubly serrate margins and red hairs on the underside. There is no significant autumn colour. |
Flower Description |
Monoecious, catkins appearing in March to early April prior to leaf emergence. Male catkins are slender, cylindrical and drooping to 4-5 cm long, purplish-brown and covered with yellow pollen. The female catkins are green, rounded to 1.25 cm and are clustered on short stalks. Pollination is anemophilous. |
Fruit Description |
The strobiles (fruiting cones) are 1.5-2 cm long, short stalked or sessile and are composed of winged seeds (samara) 2-2.5 mm long. The strobile, which resemble small pine cones turn brown in autumn and persist into the winter months. Several species of bird feed on the seed from the strobiles. |
Colour Description |
Dull green leaves, red-brown bark with pronounced grey lenticels, brown cones and little or no autumn colour. |
Texture Description |
It is a coarse textured plant and remains that way throughout the year. |
Propagation |
Natural stands occur primarily through suckering and or layering. Fresh seed may be sown in a sand based coldframe over the winter months with germination occurring in the spring. Greenhouse sown seed requires stratification of 60-90 days at 5°C. |
Ethnobotanical Uses (Disclaimer) |
It was used in the past by Indians to relieve anemia. When it is combined with powdered bumblebees it assists in the relief of pain during childbirth. Speckled alder tea was was used in the treatment of diarrhea and jaw pain as well as many other symptoms such as backaches, bruises, sore eyes and sprains. |