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Scientific Name:
Alnus rubra
Pronunciation:
AL-nus ROO-bra
Common Name:
red alder
Family Name:
Betulaceae
Plant Type:
Tree - deciduous
Key ID Features:
Leaves alternate, ovate-elliptic, 7-13cm long x 5-8cm wide, 8-15 major veins on each side of midrib about parallel; margins double serrate and rolled under; poor fall colour (leaves often fall off green); male catkins 8-15cm long, hanging in small clusters at stem tips; female catkins woody, barrel shaped 1.2-2.4cm long x 1-1.3cm wide, arise at various angles from twigs. Winter ID: new twigs three sided, becoming rounded; buds stalked, oblong, 10-14mm long, red; leaf scars raised, half-round to triangular with 3 bundle scars; persistant woody cone catkins and/ or immature male or female catkins.

Habit:
Stiffly upright
Form:
Oval - vertical
Texture:
Medium
Mature Height:
22 - 30m
Mature Spread:
7 - 10m
Growth Rate:
Fast
Origin:
B.C. west of Cascades, U.S. - northwest, U.S. - southwest
Hardiness Rating:
Zone 5: (-29 to -23 °C)
Exposure:
Full sun
Soil/Growing Medium:
Acidic, Humus rich, Well-drained
Water Use:
Moderate
Landscape Uses:
Erosion control, Native planting, Tall background, Wetland - bogs, Woodland margin
Additional Info:

Leaf Morphology:
Form:
Simple
Arrangement:
Alternate
Texture/Venation:
Soft flexible, Heavily veined, Pinnate venation
Surfaces:
Glabrous, Lustrous
Colour in Fall:
Yellow, Brown
Shapes:
Elliptic, Ovate
Apices:
Acute
Bases:
Attenuate, Obtuse
Margins:
Double serrate

Inflorescence Type:
Catkin (ament)
Flower Morphology:
Monoecious plant
Number Of Petals:
0
Colour (petals):
Not showy, Yellow
Flower Scent:
None
Flower Time at Peak:
Mar, Apr, Aug

Fruit Type:
Samara
Fruit Colour:
Brown
Fruiting Time:
Aug, Sep, Oct
Additional Info:
Not showy, Persistent, Cone-like female catkin release many tiny samaras

Bark Morphology:
Smooth, Lightly fissured, Single stem trunk
Bark or Stem Colour:
Grey, Brown
Leaf Bud Type:
Oblong, Stalked
Leaf Scar Shape:
Half-round
Organ Modifications:
Ectomycorrhizae, Root nodules (N-fixing)
Propagation:
Seed, Greenwood cuttings, Hardwood cuttings
Maintenance:
Medium
Pest Susceptibility:
Beetles or weevils, Canker or sap rot, Caterpillar or cutworm, Fungal leaf spot, Galls, Root rot, Sawflies or horntails or ants (Pest resistant, Disease resistant)

Course(s):
  • AARB 1012
  • HORT 1155
  • Level 4 Apprenticeship
Location(s):
  • (FSC)  Far South Campus
  • (JPL)  Juglans PLanting
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