BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Juncus balticus | Baltic Rush 



GENERAL BOTANICAL CHARACTERISTICS : 
Baltic rush is a thick, mat-forming, rhizomatous graminoid.  Its stems
are needle shaped and from 8 to 32 inches (20-81 cm) tall [21,29].
Leaves are basal, and branched flowerheads form on the side of the stem.
The seed pod is a pale to dark brown capsule with many seeds [33].
Botanical differences between varieties are listed below [9,21]:

J. b. var. littoralis - cyme dense to open; 1-9 cm long
J. b. var. littoralis forma dissitiflorus - cyme open & diffuse; 4-15 cm long
J. b. var. montanus - cyme compact; tepals 0.5-0.6 cm long
J. b. var. vallicola - cyme diffuse & branched; tepals 0.4-0.5 cm long
J. b. var. stenocarpus - culms 0.3-0.7 cm long 


RAUNKIAER LIFE FORM : 
   Chamaephyte
   Geophyte


REGENERATION PROCESSES : 
Baltic rush reproduces by seed and extensively creeping rhizomes
[25,29].  Mass (g m-2) and length (cm cm-3) per unit area of soil of
rhizomes, large (> 0.9 mm diameter), and fine roots were reported as
follows [25]:

Depth (cm)        Rhizomes      Large         Fine
-------------------------------------------------------
                Mass/Length   Mass/Length   Mass/Length
-------------------------------------------------------
 0-10           680.5/.27     265.3/1.83    934.1/97.09
10-20             6.9/.00     190.3/ .85    151.5/17.93
20-30             8.9/.00      97.2/ .51     71.0/ 9.23
30-40             2.9/.00      96.1/ .56     49.8/ 6.28


SITE CHARACTERISTICS : 
Baltic rush occurs from sea level to subalpine zones in montane
habitats, as well as in wet areas of Southwestern deserts, in wet
meadows, along streambanks, rivers, lakes, ponds, freshwater and
brackish marshes, and sometimes in dry flats and meadows [9,15,33].  It
usually occurs on gentle slopes, and occurs on all aspects [35].  The
water table in Baltic rush community types ranges from 13 to 39.4 inches
(33-100 cm) below the surface [27,37,38].

Soil in Baltic rush communities are poorly drained, sandy to silty
loams, often with a thick organic layer.  Soils orders and suborders
include Mollisols, Entisols, Borolls, Cryaquolls, Haploxerolls,
Fluvaquentic Haploborolls, and aquic or calcic Cryoborolls
[12,22,28,37].

Plant associates include other rushes (Juncus spp.), sedges (Carex
spp.), Kentucky bluegrass (Poa pratensis), saltgrass (Distichlis
stricta), needle spikesedge (Eleocharis acicularis), redtop (Agrostis
alba), timothy (Phleum pratense), tufted hairgrass (Deschampsia
cespitosa), red fescue (Festuca rubra), smartweed (Polygonum spp.),
dandelion (Taraxacum officinale), alkalai sacaton (Sporobolus airoides),
false Solomon's seal (Smilacina stellata), western aster (Aster
occidentalis), elk thistle (Cirsium scariosum), common silverweed
(Potentilla anserina) [4,12,22,24,27,].

Elevational ranges for Baltic rush have been reported as follows [6,35]:

Oregon        from 4,200 to 6,100 feet (1,280-1,859 m)
Wyoming       from 6,400 to 9,700 feet (1,951-2,957 m)
Colorado      from 3,400 to 11,500 feet (1,036-3,505 m)
Montana       from 4,000 to 8,900 feet (1,219-2,713 m)
Utah          from 4,200 to 9,900 feet (1,280-3,018 m)


SUCCESSIONAL STATUS : 
Facultative Seral Species

Baltic rush is a perennial, native, cool-season species [29].  It is a
climax component of several western community types and plant
associations.  However, it is usually grazing induced and an indicator
of disturbed sites [7,24,28].  In Montana pure stands of Baltic rush can
indicate disturbance or wetter phases of the Baltic rush community type
[12].  In overgrazed areas Baltic rush will replace Kentucky bluegrass,
tufted hairgrass, and Nebraska sedge (Carex nebraskensis) [24,28].  On
sandy, subirrigated rangelands Baltic rush can be replaced by balsam
poplar (Populus balsamifera), quaking aspen (P. tremuloides), and willow
(Salix spp.) [1].


SEASONAL DEVELOPMENT : 
Flowering dates in some western states have been listed for Baltic rush
[4,6]:

Colorado       May - July
Montana        June - August
North Dakota   June - August
Utah           April - May
Wyoming        May - July

The variety littoralis flowers from May through September, while the
variety stenocarpus flowers from July through September [9].

Related categories for Species: Juncus balticus | Baltic Rush