BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Spiraea douglasii | Douglas' Spirea 



GENERAL BOTANICAL CHARACTERISTICS : 
Douglas' spirea is a rhizomatous, deciduous shrub with erect, spreading
stems 3 to 6 feet (1-1.8 m) tall [17,35,40].  Leaves are 1 to 4 inches
(3-10 cm) long [20,35].  Seeds are 0.08 inch (2 mm) long [40].
Douglas'spirea forms adventitious roots after burial [1].  


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Douglas' spirea is a rhizomatous shrub that often forms dense colonies
[1,4,32].  It will sprout from the stem base and root crown following
disturbance [4,29].  In Washington following the May 18, 1980 volcanic
eruption of Mount St. Helens, Douglas' spirea showed extensive rhizome
development in the tephra (volcanic aerial ejecta) and contained one to
five adventitious roots per centimeter of stem 1 year after burial.
Maximum adventitious root length of Douglas' spirea was 3.6 inches (9
cm) [1].

Douglas' spirea produces small seeds that are probably dispersed via
animals and strong winds [40].  
  


SITE CHARACTERISTICS : 
Douglas' spirea occurs in riparian areas including wet meadows,
floodplains, terraces, bogs, swamps, and along streams, rivers, lakes,
springs, and ponds [4,12,17,23,24].  

Douglas' spirea grows best on moist to semiwet soils with good drainage
[20,28,29,32,35].  It grows best on loam and sandy loam soils, but
occurs on silty clay, clay loam, and gravelly substrates as well
[17,19,23,29,42].  Douglas' spirea is tolerant of permanently
water-logged soils (peat) and widely fluctuating water tables [23,28].  

Elevations for Douglas' spirea are as follows:

                           feet                 meters

California              4,620-6,435           1,400-1,950     [20,46]
Montana                 3,760-6,700           1,147-2,044     [4,35]
Oregon                  2,200-5,800             660-1,740     [29]
Washington              2,500-5,000             750-1,500     [19]


SUCCESSIONAL STATUS : 
Douglas' spirea occurs mostly in seral communities [2,4,7,27,37].  It is
generally shade intolerant [28], but horticultural specimens have been
described as shade tolerant [11,20].  In British Columbia Douglas'
spirea is a pioneer species in disclimax communities maintained by
avalanches [2].  In southwestern British Columbia and northwestern
Washington, Douglas' spirea is a pioneer species on clearcut sites
[27,37].  In northwestern Montana a Douglas' spirea community type may
be seral to an as yet undefined thinleaf alder/Douglas' spirea habitat
type [4].  

Douglas' spirea often forms dense impenetrable thickets in riparian
areas [4].  In Washington Douglas' spirea usually occurs in mosaics with
other hydric and mesic non-forest species in riparian forest openings
[19].  
 


SEASONAL DEVELOPMENT : 
In California Douglas' spirea flowers from June to September [40].  

Related categories for Species: Spiraea douglasii | Douglas' Spirea