BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Salix myrtillifolia | Blueberry Willow 



GENERAL BOTANICAL CHARACTERISTICS : 
Blueberry willow's two varieties differ significantly in growth form.
Low blueberry willow is a much-branched, low-growing, and often
prostrate shrub typically between 8 and 24 inches (20-60 cm) tall.  Tall
blueberry willow is an erect shrub often 6 to 8 feet (2.0-2.5 m) tall
but is occasionally taller [26].  Both varieties have relatively small,
simple, alternate, deciduous leaves.  Male and female flowers occur on
separate plants in 3/4- to 2-inch-long (1.5-5 cm) erect or ascending
catkins.  The fruit is a two-valved capsule [22,26].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Blueberry willow's primary mode of reproduction is sexual.  It produces
an abundance of small, lightweight seeds.  Like most willows, it
probably begins seed production at an early age (between 2 and 10 years)
[13].  At maturity, the fruit splits open, releasing the seed.  Each
seed has a cottony down that aids in dispersal by wind and water.  The
seeds are dispersed during the growing season and remain viable for only
about 1 week without moisture.  Viable seeds will germinate within 24
hours of dispersal on moist seedbeds [6].  In germination tests, 97 to
100 percent of blueberry willow (both varieties) seeds germinated within
1 to 3 days at temperatures between 50 and 77 degrees F (10-25 C) [9].
Exposed mineral soils provide the best seedbed [6].

Vegetative reproduction:  Most willows are prolific sprouters.  It is
assumed that blueberry willow also sprouts from the root crown or
stembase if aboveground stems are broken or destroyed by cutting,
flooding, or fire [13].  Detached stem fragments form adventitious roots
if kept moist.  Thus, tall blueberry willow stem fragments transported
by floodwaters develop into new plants when deposited on riverbars
[3,8].  In muskegs and bogs, low blueberry willow commonly reproduces by
layering as the lower branches are overgrown with sphagnum [5].


SITE CHARACTERISTICS : 
Low blueberry willow typically occupies poorly drained bogs, swamps, and
black spruce (Picea mariana) muskegs [10,26].

Tall blueberry willow occupies better drained sites.  It is common in
willow thickets along streambanks and riverbanks, and also grows along
roadsides, lakeshores, and prairie margins [3,26].  It is common on
siltbars and sandbars of the Tanana and Yukon Rivers [26].  Frequent
associates include bog birch (Betula glandulosa), alder (Alnus spp.),
balsam poplar (Populus balsamifera), and numerous species of willow
[3,25,26].


SUCCESSIONAL STATUS : 
Low blueberry willow is an early seral species that becomes locally
abundant following disturbances which expose mineral soil and create an
open canopy.  It occurs in early seral stages following burning in
low-lying black spruce stands [26].

Tall blueberry willow is also seral.  It is one of the first willows to
colonize recently deposited river alluvium on interior Alaska
floodplains.  Floodplain willow communities are short-lived; thinleaf
alder (Alnus incana ssp. tenuifolia) and balsam poplar typically
establish within 5 years of initial willow colonization.  By 20 to 30
years, poplars begin to overtop the brushy canopy and dominate.  By this
stage in succession, overstory shade has eliminated most tall blueberry
willows, but some may persist as scattered individuals [24,25].


SEASONAL DEVELOPMENT : 
In Alaska, low blueberry willow catkins appear after the leaves have
begun to develop.  Seeds are dispersed during the growing season, about
mid-June [9,26].  

In Alaska, tall blueberry willow catkins appear after the leaves have
begun to develop.  Flowering is in early to mid-June, seeds mature in
late June to mid-July, and catkins fall in late July [26].
  

Related categories for Species: Salix myrtillifolia | Blueberry Willow