BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Andropogon gerardii var. paucipilus | Sand Bluestem 



GENERAL BOTANICAL CHARACTERISTICS : 
Sand bluestem is a native, warm-season, perennial, rhizomatous tallgrass
that grows 3 to 6 feet (1-2 m) tall.  Well-developed rhizomes reach
lengths of 4 to 8 inches (10-20 cm) in climax stands but only about 4
inches (10 cm) in recently vegetated shifting sands [58,61].  Root
depths vary from 6 to 10 feet (1.8-3 m) [61].


RAUNKIAER LIFE FORM : 
   Cryptophyte


REGENERATION PROCESSES : 
Sand bluestem is a poor seed producer. Tolstead [58] noted that in
Nebraska seeds seldom formed even in well-developed communities.  Sims
and others [51] observed that only 36 percent of shoots of the cultivar
'Elida' developed seed heads.  In sand bluestem stands in Kansas,
Cornelius [15] observed that only 13.3 percent of florets contained
caryopses.  Seed does not require cold treatment to germinate [56].
Seeds germinate in the fall and overwinter as seedlings.  Stubbendieck
and McCully [52] noted that although high temperatures favored
germination, lower temperatures favored seedling survival.

Most reproduction in sand bluestem occurs via rhizomes.  Rhizomes grow
from axillary buds during June and July, turn upward in late summer, and
then remain dormant, ready for shoot growth the following spring [51].


SITE CHARACTERISTICS : 
Sand bluestem is found almost exclusively on sandy soils.  It is most
common on sandhills, windblown sand dunes, and high and low sandy
plains.  It is only occasionally found on moderately coarse soils [53].
In the Northern and Central Great Plains, sand bluestem appears to be
restricted to the upper and middle elevations of sand dunes and
sandhills [3,5,6,51].  This preference is apparently related to soil
moisture.  In sandhills, there is very little soil development because
of wind erosion.  Here coarse-textured sands are found at the tops of
dunes, and the finer sands near the bottom.  The sandy characteristic of
the soil at the upper reaches of the sand dunes allows for deep water
percolation with very little runnoff.  This water is stored at depths
below 23.5 inches (60 cm) and is available to deeply rooted species such
as sand bluestem throughout the growing season, even during dry summer
periods [4].

Sand bluestem's importance in a plant community tends to decrease as
sand content of the soil decreases.  Finer textured soils do not absorb
water as efficiently, nor does the water percolate as deeply, as in
sandy soils.  On these sites, sand bluestem must compete with
shallow-rooted grasses, such as Stipa, Agropyron, and Bouteloua spp.,
which are better able to extract moisture in this soil type.  Barnes and
Harrison [4] observed that sand bluestem plants growing on fine-textured
soils at the lower slopes of sand dunes experienced greater water stress
than plants growing at mid or upper slopes.

Elevational ranges for sand bluestem in several western states are as
follows [8,19,25,62]:

     under 5,000 feet (1,524 m) in the Rincon Mountains, AZ
     from  3,500 to 5,200 feet (1,067-1,585 m) in CO
           3,000 to 7,000 feet ( 914-2,134 m) in NM
           2,800 to 3,800 feet ( 853-1,158 m) in MT
           4,100 to 4,800 feet (1,250-1,463 m) in WY
           4,600 to 5,800 feet (1,400-1,770 m) in UT


SUCCESSIONAL STATUS : 
Facultative Seral Species

Sand bluestem occurs in a variety of successional stages, from recently
vegetated shifting sands to climax grassland communities [46,58,61].  It
is a pioneer on sand blowouts where it often dominates with blowout
grass (Redfieldia flexuosa), prairie dropseed (Sporobolus heterolepis),
and hairy prairie clover (Helianthus periolaris) [12].  In more mature
stands it is often found with prairie sandreed, sandhill lovegrass
(Eragrostis trichodes), sand dropseed, sandhill muhley (Muhlenbergia
pungens), and needle-and-thread grass (Stipa comata) [46,57,58].


SEASONAL DEVELOPMENT : 
Regrowth of sand bluestem occurs in late spring.  Shoots originate
primarily from axillary buds and apical meristems of short, terminal
rhizomes [51].  Studying the growth of the cultivar 'Elida in eastern
Colorado, Sims and others [51] observed that 26 percent of blade growth
occurred by May 29, 81 percent by June 30, and 99 percent by July 28.
Most of the leaves were dry by September 5, and all were dry by October
14.

Sand bluestem exhibits ecotypic variation in relation to the time of
flowering and maturity.  Plants from the northern and western areas of
its range flower earlier than plants growing in the southern and eastern
portion of its range [38,40].  Flowering dates in several states was
reported as follows [19,26,33,58]:

Location                 Beginning of flowering      End of flowering

  CO                            July                     Sept
  MT                            July                     Sept
  ND                            July                     Aug
  NE                            July                     Sept
  TX                            Aug                      Nov
  WY                            July                     Sept

Phenology of two sand bluestem cultivars grown in Fergus Falls,
Minnesota was reported as follows [42]:

                                         'Garden'      'Goldstrike'
                                      (origin w NE)    (origin nw NE)

1st emergence of inflorescence,         July 28           August 4
  10 culms or more
1st anthesis, 10 culms or more          July 30           August 8
50% emergence of inflorescence          August 16         August 23
1st seed mature                         August 21         August 24
Seed mature - starting to shatter       October 9         October 9

Related categories for Species: Andropogon gerardii var. paucipilus | Sand Bluestem