Ceanothus – derived from keanothos, an ancient Greek name relating to some plants in the buckthorn family (Rhamnaceae)

Native range: Western North America

Leaves:

• alternate
• shallowly serrate
• margins sometimes gland-toothed
• pinnately veined or w/ 3 main veins from the base (especially prominent on the underside of the leaf)

Flowers:

• inflorescence – cluster in leaf axils (spike or panicle)
• perfect
• small petals
• 5 stamens, opposite petals
• 3 carpels
• intense blue (~white)
• 5-merous

Fruit:

• capsule
• fruit separating at maturity into 3 dehiscent nutlets

Other notes:

• small shrub or tree to 20 ft.
• ~thorny
• mostly evergreen, can be deciduous
• popular garden plant but several native species occur in the PNW
• C. thyrsifolius and cultivar Puget Blue are common here
• C. gloriosus (Point Reyes C.):
  • low and prostrate
  • blue flowers
  • dark green leaves
  • good in hot dry conditions

Ecology & Adaptations:

• C. thyrsiflorus (Blue blossom, California lilac)
  • native from SW Oregon to Southern California
  • found in the Coastal Range foothills
• C. prostratus (mahala mat, squawcarpet)
  • native to: east slope of the Cascades in Washington from Yakima County south; Washington south to California; east to Idaho and western Nevada
  • found in drier open woods, moderate to mid-elevations in the mountains
• C. sanguineus (redstem ceanothus, Oregon teatree)
  • native to and widely distributed on both sides of the Cascades in Washington; BC to California, east to Idaho
  • found in moist to dry open woods, low to moderate elevations
• deciduous:
  • C. velutinus (mountain balm, greasewood, sticky-laurel, tobacco-brush)
    • native to and widely distributed on both sides of the Cascades in Washington; BC to California, east to South Dakota and Colorado
    • found in moist to dry open forests, low to mid-elevations in the mountains
• evergreen:
  • C. integerrimus (deerbrush)
    • native east of the Cascades in Washington along and near the Columbia; Washington south to Baja California
    • found in dry, open forests and open areas at low to moderate elevations on gentle to steep slopes
    • drought-deciduous (i.e., survives drought by dropping its leaves)
• pollinated by hummingbirds, honey bees, and bumble bees
• seed dispersal – ripe seed is forcibly ejected from the capsule when the capsule dries and splits
• tolerates low-nutrient levels – a species of N-fixing bacterium, Streptomyces, inhabits Ceanothus root nodules, enabling the genus to handle low-nutrient conditions
• fire/disturbance adapted:
  • regenerates after fire and herbivory by resprouting from root crown and/or stem
  • may spread laterally by layering
  • early successional species that establishes on sites after fire, landslide, or other stand-replacing event
  • N-fixing bacteria in root nodules provides essential nutrients in disturbed environments
  • primary means of re-establishment after fire is seeds, which are produced in abundance and may remain viable for over 20 years, until the hard seed coat is scarified by fire
  • establishment is best on bare mineral soil, such as that found after fire