BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Salvia mellifera | Black Sage 



GENERAL BOTANICAL CHARACTERISTICS : 
Black sage is a native, semideciduous, subligneous, malacophyllous
(soft-leaved) subshrub that grows between 3.3 and 6.6 feet (1-2 m) tall
[16,21,32,40,55].  Plants are openly branched and spreading [16,40,47].
The square stems are green or purple when young but turn brownish-gray
with age [2].  The aromatic leaves are dark green and wrinkled above
with lighter-colored undersides [2,40].  Flowers are 0.5 inch (1.25 cm)
long, pale blue or white, and arranged in compact whorls spaced at
intervals along the flowering stalk [2,40].  The fruit is a smooth, dark
brown, dehiscent nutlet approximately 0.08 inch (2 mm) long [22,40].
Black sage is shallow rooted [16].  The much branched and fibrous root
system rarely extends 2 feet (0.6 m) below the soil surface with the
majority of roots concentrated in the top 5 inches (12.5 cm) of soil
[14,16].  Longevity of black sage is estimated at 20 to 30 years
[16,32].


RAUNKIAER LIFE FORM : 
   Undisturbed State:  Phanerophyte (nanophanerophyte)
   Burned State:  Hemicryptophyte 


REGENERATION PROCESSES : 
Black sage reproduces by both sexual and vegetative means.  Seedling
recruitment and vegetative regeneration occur immediately following fire
as well as during extended fire-free intervals [20,21,32].

Seed reproduction:  Black sage flowers almost annually once plants have
established [22].  The small, lightweight seed is widely dispersed
during the summer [22].  Although seed longevity is not documented for
black sage, seeds of closely related chia remain viable for at least a
decade under laboratory storage [20].

Black sage exhibits a complex germination behavior that permits seedling
establishment under a number of environmental conditions.  Because seed
germinates readily when exposed to light [25,36], black sage invades
disturbed areas.  Keeley [21] recorded 23 percent germination when seeds
were incubated in the light at 73 degrees F (23 deg C).  Most seeds
germinated within the first week.  Germination increased to 50 percent
when seeds were exposed to alternating temperatures of 55 degrees F and
79 degrees F (13 degrees C and 26 degrees C) for 12 hours each.  Keeley
[20] suggests that alternating diurnal temperatures such as these are
likely near the soil surface of gaps within undisturbed chaparral and
coastal sage scrub communities and may account for black sage seedling
recruitment in canopy gaps.  Germination is inhibited by darkness [20].
Seeds buried in the soil remain dormant and require the presence of
charred wood for germination [21].

Vegetative regeneration:  Black sage may spread vegetatively by
producing adventitious roots along decumbent branches [14,58].
Established individuals also rejuvenate their canopies through the
continual production of new basal sprouts from epicormic buds at the
stem base [32].  Following disturbances such as fire or cutting, black
sage sprouts from surviving adventitious buds on the root crown
[20,33,59].


SITE CHARACTERISTICS : 
Black sage typically occurs at low elevations on the coastal and inland
sides of the California Coast Range.  Sites include dry slopes and
benches below 3,000 feet (915 m) [2,40].  Dominant Salvia species
segregate by moisture preference within coastal sage scrub communities
[51,54].  Relative to other Salvias, black sage occupies more mesic
habitats [28,29,51].  It is common on coarse-textured soils including
those derived from unconsolidated sand, limestone, sandstone, and
serpentine [16,28,51].  Within Venturan coastal sage scrub communities,
black sage prefers coarser-textured soils and more southerly aspects
than purple sage [54].  Whereas annual precipitation on black sage
dominated sites may average 14.5 inches (36.2 cm), sites dominated by
purple sage receive 13.6 inches (33.9 cm) of annual precipitation [54].
Although black sage may occur as scattered individuals [4] or intermixed
with other Salvia species, it often forms pure, monospecific stands that
extend over large areas [28,51,54].


SUCCESSIONAL STATUS : 
Black sage is a short-lived, shade-intolerant species that nonetheless
produces self-perpetuating stands within coastal sage scrub communities
[28,52,54].  Continual seedling recruitment within intact stands and
basal sprouting by established individuals allows black sage to maintain
vigorous, mixed-aged stands during extended fire-free intervals [53].
Stands unburned for 60 years do not appear senescent [32,53].  Within
Venturan coastal sage scrub communities, black sage attained highest
cover in tall-canopied, older stands exhibiting substantial litter
buildups [51].  On these sites black sage is a keystone species that
controls the composition and abundance of herbaceous associates [54].
Evidence suggests that it influences the associated flora through
biotic-control factors such as allelopathy [37,38,39], shading [49], and
the selective herbivory of associated rodents [53,54].

Black sage typically occupies gaps within the chaparral canopy.
Although seedlings rapidly invade recent burns within drier chaparral
communities, maximum cover occurs during postburn years 3 and 4 and
subsequently declines as the stand matures [60].  In chaparral stands
over 20 years of age, black sage recruits seedlings in canopy gaps and
may form enclaves [53].


SEASONAL DEVELOPMENT : 
Black sage is a herbaceous perennial that becomes woody at the base
[26].  Plants die back somewhat in the winter and produce new growth in
the spring.  Like many associated coastal sage scrub dominants, black
sage is a semideciduous or seasonally dimorphic species [52].  Large
leaves develop on main shoots during the winter when moisture is most
abundant and these are dropped over the summer drought period.  Smaller,
axillary leaves are produced immediately following the formation of
main-shoot leaves but are retained until the following winter [52,53].

Black sage typically blooms from March to June [9,40].  Flowering
coincides with the early season activity of solitary, native bees [9].
Phenological development of black sage on chaparral sites in the Santa
Monica Mountain foothills is presented below [48]:

    growth initiated                 September - following autumnal
                                                   rains
    main period of stem elongation     March - late May
    flower stalks dried                June
    early season leaves dropped        June
    stem growth terminated             June

Related categories for Species: Salvia mellifera | Black Sage