Alnus rubra (Red Alder)


Botanical Information

FamilyBetulaceae
GenusAlnus
Speciesrubra
CategoryWoody
TypeTree (deciduous)
OriginCanada, United States (Alaska to California, coastal areas)
Pronunciation

Details

USDA Hardiness Zone6
USDA Hardiness Ref.
Canadian Hardiness Zone5 - 6a
Canada Hardiness Ref.
RHS Hardiness ZoneH7 - H6
RHS Hardiness Ref.
Temperature (°C)(-23) - (-18)
Temperature (°F)(-10) - 0
Height30 m
GrowthMedium
Flowering PeriodApril, May

Description and Growing Information

General DescriptionThis tree has been placed on the IUCN Red List as least concern.
ShapePyramidal tree with slender crown.
CultivationVery tolerant of infertile or wet sites.
Notable SpecimensWakehurst Place, Ardingly, Haywards Heath, Sussex, England.
Bark/Stem DescriptionShoots are angled and sticky, appearing first as a dark red.
Flower/Leaf Bud DescriptionBus are red with glandular-resinous scales.
Leaf DescriptionLeaves are 8-17 x 5-11 cm, occasionally up to 20 cm, with dark green colouring above, and grey or blue-grey beneath with red-brown pubescence.
Flower DescriptionMale catkins 10-15 cm, slender, appearing in clusters of 3-5.
Fruit DescriptionFruit catkins to 3 cm, barrel-shaped, in clusters of 3-6 on orange-red pedicels.

Photographs