BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Ribes americanum | American Black Currant 



GENERAL BOTANICAL CHARACTERISTICS : 
American black currant is a native, deciduous shrub growing from 3.3 to
5 feet (1-1.5 m) tall [16].  Its many erect branches lack spines
[9,13,16].  The three- to five-lobed, suborbicular leaves are 1.2 to 3.2
inches (3-8 cm) wide and gland-dotted beneath [8,13,16,17].  Drooping
racemes are five- to ten-flowered [13,16].  The globose berries are
smooth and contain many seeds [13,16,38].  


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
American black currant reproduces mainly by seed.  The ability of
American black currant to sprout from the root crown has not been
described in the literature.

Shrubs of Ribes spp. begin fruiting after 3 years [4].  Many seeds fall
beneath the parent plant; they are also dispersed by birds and mammals
[35,36].
  
Mineral soil and scarification generally enhance germination in Ribes
spp.  [35,36,44].  Results of germination experiments on American black
currant are variable.  In Montana, no germination was obtained when
American black currant fruit was fermented, aerated for 2 weeks, flailed
mechanically in water, and washed on screens [9].  In Dun County,
Wisconsin, seeds were obtained from green berries, almost-mature
berries, and mature berries.  They were refrigerated for 6 months,
soaked in water for 10 days, and placed on moist blotting paper at 59
degrees Fahrenheit (15 deg C).  After 13 months, only one seed, from a
"mature" berry, had germinated [11].  A germination rate of 76 percent
was obtained by stratifying American black currant seeds at 28 and 36
degrees Fahrenheit (-2.2-2.2 deg C) for 90 to 120 days.  Seeds were
stratified and germinated in sand moistened with nutrient solution [26].
Hoyle [18] reported that chilling American black currant seeds at 38.3
degrees Fahrenheit (3.5 deg C) for 15 weeks promoted germination.

Fallen seeds of Ribes spp. may remain viable in the soil and duff for
many years [35,36].  The viability of American black currant seeds from
herbarium specimens 3 to 9 years old was tested.  Fourteen seeds were
extracted and planted in peat at 40 to 77 degrees Fahrenheit (10-25 deg
C) daily alternation.  No seeds had germinated by the fourteenth week.
Drying Ribes seeds may induce dormancy [11].


SITE CHARACTERISTICS : 
American black currant has wide ecological amplitude.  It occurs in
swamps [17,25], in moist woods and canyons [9,17,23], along roadsides,
and on plains, foothills, and mountains [9,16,39,42].  It grows on
clayey, sandy, and rocky soils [9,39,42].  In Colorado, the elevational
range of American black currant is 3,500 to 8,000 feet (1,050-2,400 m)
[16].  On the Pine Ridge escarpments in Nebraska, American black currant
occurs from 2,500 to 4,500 feet (750-1,350 m) [39].

The Pine Ridge escarpments receive an average annual rainfall of
approximately 18 inches (45.72 cm), and summer drought is frequent.  The
average frost-free period is 145 to 150 days [39].  On the eastern edge
of Michigan's Upper Peninsula, where American black currant occurs in
alder swamps, climate is continental with modification by Lake Superior.
The average annual rainfall is 31 inches (780 mm).  The average annual
snowfall is 96 inches (2,500 mm).  The average summer temperature is 63
degrees Fahrenheit (17 deg C), and the mean frost-free period is 116
days [25].


SUCCESSIONAL STATUS : 
American black currant is somewhat shade tolerant.  It often grows in
moist forests [9,13,16,23].  In Long Grove, Illinois, American black
currant grows in closed canopied woodlands [2].  In Minnesota, very
dense balsam fir (Abies balsamea) or northern white-cedar (Thuja
occidentalis) overstories suppress Ribes spp. [3].


SEASONAL DEVELOPMENT : 
American black currant flowers May through June [23], and seed ripens
from mid-August through early September [9].  Near Woodworth Stutsman
County, North Dakota, Callow and others [6] recorded the following
phenological dates for American black currant from 1979 to 1984:

earliest first bloom				        5/12/80
latest first bloom					6/06/79
median date of first 10 plants with flowers		5/18
median date of full flowering				5/21
median date when flowering was 95% complete	        6/9
mean length of flowering period			        22 days  

Related categories for Species: Ribes americanum | American Black Currant