Lupinus arboreus Sims
tree lupine (yellow bush lupine)
Fabaceae (Pea family)
Introduction to Vascular Plants
tree lupine (yellow bush lupine)
Fabaceae (Pea family)
Introduction to Vascular Plants
Introduction
Tree lupine, or yellow bush lupine, is found in North America along the north and central Pacific coast, often in coastal bluffs and dunes, but has naturalized further north (Riggins and Sholars 1993). It is an introduced and invasive species in British Columbia, and has naturalized in coastal areas of the southwestern part of the province. On the mainland, it has been reported from Powell River, Delta and New Westminster (Annacis Island and Lulu Island). On Vancouver Island, it has been reported from Tofino, the Wickaninnish dunes, Sooke, and Swartz Bay. It is particularly abundant in the Sooke area where it occurs interspersed with Scotch broom. While lupines can be difficult to identify, this species is easy to recognize. It can reach heights of six or seven feet, and is the only shrub species of lupine found in BC. It has distinctive yellow (sometimes grading to blue) flowers (Riggins and Sholars 1993). It is an aromatic, sweet-smelling plant that readily attracts pollinators.
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Species Information
General:
Short-lived, somewhat shrubby perennial from a woody stem-base and deep heavy root; stems erect, 1-1.5 (2) m tall, much-branched with numerous leafy, short branches in the axils of the main leaves, short-hairy to silky-hairy.
Leaves:
Alternate, palmately compound with 5 to 11 leaflets; leaflets oblanceolate, 3-6 cm long, 4-7 mm wide, short-hairy to silky on the lower surface.
Flowers:
Inflorescence a terminal, stalked raceme of pea-like, more or less whorled flowers; corollas yellow or white to sometimes bluish, 14-20 mm long on stalks 4-9 mm long, the banner glabrous and bent backwards at the midpoint, the wings glabrous, the keel fringed with hairs along the upper edges; calyces silky-hairy, the upper lip 2-toothed, the lower lip entire and boat-shaped.
Fruits:
Pods, 4-6 cm long, about 1 cm wide, long-soft-hairy; seeds 8 to 12, dark brown, 5 mm long.
Illustration
If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.
Illustration Source: The Illustrated Flora of British Columbia
USDA Species Characteristics
Flower Colour:
Yellow
Blooming Period:
Mid Spring
Fruit/Seed characteristics:
Colour: Brown
Present over the Summer
Source: The USDA
Ecology
Ecological Framework for Lupinus arboreus
The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)
The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)
| Site Information |
Value / Class |
||
|
Avg |
Min |
Max |
|
| Elevation
(metres) |
1048 | 1046 | 1051 |
| Slope
Gradient (%) |
13 | 4 | 30 |
|
Aspect (degrees) |
62 | 72 | 356 |
| Soil
Moisture Regime (SMR) [0 - very xeric; 4 - mesic; 8 - hydric] |
4 | 4 | 5 |
| Modal
Nutrient Regime
Class |
C | ||
| #
of field plots species was recorded in: |
3 | ||
| Modal
BEC Zone Class |
SBPS | ||
|
All BEC Zones (# of stations/zone) species was recorded in |
MS(1), SBPS(2) | ||
|
Source:
Klinkenberg 2013
|
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Habitat and Range
Dry to mesic bluffs, sandy beaches, eroding banks and other disturbed sites; rare on SE Vancouver Island, the Gulf Islands and adjacent mainland; introduced from CA.Status Information
References
Rhonda Riggins and Teresa Sholars. 1993. Lupinus arboreus treatment. In: Hickman, James C. The Jepson Manual of the Higher Plants of California. University of California Press, Los Angeles.