BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Potentilla recta | Sulfur Cinquefoil 



GENERAL BOTANICAL CHARACTERISTICS : 
Sulfur cinquefoil is an introduced, perennial, long-lived forb with one
to several stems growing from a woody caudex.  The erect, stout stems
are 12 to 28 inches (30-70 cm) tall.  The leaves have five to seven
coarsely serrate oblong leaflets.  The small seeds are slightly
flattened and 0.05 inch (0.12 cm) long.  The taproot may exhibit some
lateral growth, but there are no rhizomes.  Individual plants
approximately 25 to 30 years old have been found in Michigan, and
20-year-old plants are not unusual [18,19,26].


RAUNKIAER LIFE FORM : 
   Hemicrytophyte


REGENERATION PROCESSES : 
Although sulfur cinquefoil reproduces primarily by seed, it has an
unusual method of vegetative reproduction.  Annual regrowth each spring
eventually causes individual sulfur cinquefoil plants to become several
closely spaced, independent plants.  Each year new shoots appear on the
outer edge of the woody caudex.  The old, central portion rots away and
completely disintegrates within 6 to 8 years.  The remaining living
portions form a ring-shaped clump composed of several individuals
[19,26].  Wild carrot seedlings have been observed growing in the clump
center [26].
  
Most sulfur cinquefoil seeds are produced by cross-fertilization, but a
few are produced by self-fertilization.  In an old field abandoned for
10 years, sulfur cinquefoil averaged 61.5 seeds per flower, 25 flowers
per stem, and 1.1 stems per plant.  Thus, an average plant produced
approximately 1,650 seeds [26].  The seeds do not have a special
dispersal mechanism [21].

Seeds germinate when exposed to light if soil moisture is not limiting.
Some fresh, mature seeds exhibit dormancy, but buried seeds are
generally not dormant despite yearly changes in temperature.  In one
study in Kentucky, sulfur cinquefoil seeds were buried 2.8 inches (7 cm)
deep.  Each month for over 2 years, some seeds were exhumed, and
germination was tested in light and dark conditions at five alternating
day/night temperature regimes:  59/43, 68/50, 77/59, 86/59, and 95/68
degrees Fahrenheit (15/6, 20/10, 25/15, 30/15, and 35/20 deg C).
Percent germination fluctuated between 35 and 100 percent for the four
coolest temperature regimes.  The warmest regime showed erratic
germination from 2 to 71 percent suggesting that germination may not
occur in July and August when temperatures are high [2].

Documentation of sulfur cinquefoil seeds in seedbanks was not found in
the literature, but sulfur cinquefoil appears to be a persistent
seedbank species.  Percent germination of sulfur cinquefoil seeds did
not decrease with more than 2 years burial [2].  Rice and others [20]
suggest that sulfur cinquefoil seeds remain viable in the soil for more
than 4 years.

Soule and Werner [21] studied the reproductive effort (the proportion of
aboveground biomass allocated to reproductive parts) in sulfur
cinquefoil in three old fields in Michigan.  The average reproductive
effort ranged from 16 to 28 percent, but differences within and between
populations were not statistically significant [21].

Sulfur cinquefoil stems that are knocked to the ground can produce roots
at the nodes [27].


SITE CHARACTERISTICS : 
Sulfur cinquefoil grows on roadsides, waste places, unworked fields,
pastures, prairies, and along fencerows.  It grows under a variety of
climatic conditions.  In Canada, sulfur cinquefoil occurs in areas with
30 to 50 inches (750-1,250 mm) mean annual precipitation [26].  Sulfur
cinquefoil has also been reported growing on a site in western Montana that
receives 13 to 16 inches (330-410 mm) mean annual precipitation [13].

Sulfur cinquefoil grows on dry sandy, gravelly, and rocky soils
[1,15,19,26].  It occurs at low to middle elevations in Montana [19].


SUCCESSIONAL STATUS : 
Sulfur cinquefoil is an early successional species but persists into
later seres until an extensive woody cover is present [21,26].  Sulfur
cinquefoil was present on old fields in Michigan abandoned from
cultivation 5 and 15 years previously but was not a major species on a
field abandoned for only 1 year [11].  Sulfur cinquefoil is common in
the mixed herbaceous perennial stage of old-field succession which
usually predominates 11 to 15 years after abandonment from grain crops
and 16 to 20 years after abandonment from cultivated fields and hay
fields [4].  Sulfur cinquefoil occurred in three old fields in Michigan
which received 51 to 84 percent of full sunlight.  The lowest light was
a shrubby habitat dominated by staghorn sumac [21].  Sulfur cinquefoil
does not occur under a dense forest canopy [26] and thus is probably
intolerant of shade.

Sulfur cinquefoil is reported to be very competitive.  In Montana, it
invades bluebunch wheatgrass (Pseudoroegneria spicata) rangeland in good
condition [20].  Densities as high as 3.5 flowering stems per square
foot (39/sq m) have been reported for sulfur cinquefoil in Michigan
[26].  It is actually replacing spotted knapweed, an aggressive weed
species, on some sites in Montana [18].


SEASONAL DEVELOPMENT : 
In Michigan and in New England, sulfur cinquefoil flowering begins in
early June and continues until early August [9,26].  In Montana, sulfur
cinquefoil begins to bloom in late May [20].  Peak flowering generally
occurs in late June [26].  Seeds germinate at anytime during the growing
season provided soil moisture is not limiting and alternating day/night
temperatures are less than 95/68 degrees Fahrenheit (35/20 deg C) [2].
Growth begins early in spring [20].

Related categories for Species: Potentilla recta | Sulfur Cinquefoil