BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Rosa acicularis | Prickly Rose 



GENERAL BOTANICAL CHARACTERISTICS : 
Prickly rose plants are quite variable in morphological details
including pubescence, glandularity, and fruit shape [87].  Prickly rose
is a deciduous shrub about 4 feet (1.2 m) in height with many fine roots
in the top 8 inches (20 cm) of soil.  Deep roots may extend to 55 inches
(140 cm) [73].  The main stems are usually covered with slender,
straight bristles or prickles.  The alternate leaves are pinnately
compound with five to nine leaflets and conspicuous stipules [28,72].
The pink or rose-colored flowers have numerous stamens and are borne
singly on lateral branches.  The globose, fleshy, red or orange-red hip
has 10 to 30 achenes.  Each achene is 0.15 to 0.2 inch (3.8-5 mm) long
with stiff hairs along one side [28,37,72].

Information about subspecies (varieties) is summarized below [72,87]:

    Subspecies (variety) acicularis is octoploid (2n = 56).  It has
glandular pedicels and narrow sepals (less than 0.1 inch or 3 mm).  Its
leaves have five leaflets.

    Subspecies sayi (variety bourgeauiana) is hexaploid (2n = 42).  Its
pedicels are glabrous and the sepals are wider than 0.1 inch (3 mm).
There are five to nine leaflets in each leaf.


RAUNKIAER LIFE FORM : 
   Undisturbed State:  Phanerophyte (nanophanerophyte)
   Burned or Clipped State:  Hemicryptophyte
   Burned or Clipped State:  Cryptophyte (geophyte)


REGENERATION PROCESSES : 
Prickly rose regenerates vegetatively by means of widespread rhizomes.
A single clone with 8 to 11 aboveground stems linked by a horizontal
rhizome can cover 11.95 to 23.92 square yards (10-20 sq m).  Results of
an Alaskan study found rhizomes between 8 and 12 inches (20-30 cm) deep.
This was sufficient for the rhizomes to be in the mineral soil below
deep organic horizons [10].  Since rhizomes sprout after fire and other
types of disturbance, prickly rose clones may live for hundreds of years
[17].

Prickly rose flowers and sets seed frequently in open communities and
infrequently under a canopy [46].  Seed is dispersed by small mammals,
song birds, and grouse [1].  Seeds exhibit deep dormancy and require
warm stratification for the initial stages of germination, followed by
cold stratification for germination to continue [10,17,54,90].  While
most seeds germinate following snowmelt the second spring after seed
set, germination of one seed crop may spread over several years [17].


SITE CHARACTERISTICS : 
Prickly rose is a characteristic species of boreal forests under white
spruce and relatively open black spruce.  It is very common in northern
hardwood forests composed of paper birch (Betula papyrifera), aspen
(Populus tremuloides), and cottonwood (Populus spp.), and in
transitional zones between birch and spruce forest.  It is less frequent
in closed black spruce forests [9].

In the northern Great Plains and Alberta, it is found on wooded
hillsides, along streambanks, and on rocky bluffs and ledges [28,72,90].
Near the Great Lakes, prickly rose is found on sandy and gravelly
shores, and sandy woodlands with jack pine (Pinus banksiana) and oak
(Quercus spp.).  It also grows on rocky ridges and shores, in moist
thickets, in swamps, and in openings in conifer forests [87].  Prickly
rose grows on active floodplains [26,54,76,81,90].

In Alaska, prickly rose is common with aspen in old burns and is found
in thickets, alongside roads, and in bogs [84].  

Soil relationships:  In interior Alaska and on the Saskatchewan and
MacKenzie river deltas, prickly rose does best on soils based on
alluvium that may be seasonally flooded.  However, it does not do well
on peats or in basins with restricted drainage [18,20,57].  From
British Columbia to Manitoba prickly rose does well on a variety of soil
textures and soil moisture regimes and it has good drought tolerance
[14,64,90].  In Alberta, prickly rose does not seem to grow on the
poorest sites, although in Alaska it grows on gravels that are low in
nutrients and susceptible to rapid freezing and thawing [14,90].  In
British Columbia subboreal spruce stands, prickly rose is characteristic
of mesic and mesotrophic sites on both fine and coarse textured soils
[42,61].  A Minnesota report describes it as growing on sites that range
from poor and dry to moderate [5].  


Elevation:  Elevational ranges in some western regions are [14,19]:

                     Minimum                   Maximum
                   feet      meters         feet      meters

Alberta           1,650        500          6,550     2,000
Colorado          4,500      1,372         10,900     3,322
Montana           3,300      1,006          9,000     2,743
Wyoming           5,000      1,524         10,900     3,322


SUCCESSIONAL STATUS : 
Prickly rose is moderately shade tolerant [90].  In Minnesota forests,
this is evident from reported frequencies of 71 to 100 percent in the
open and 1 to 40 percent under a canopy [5].  Around Lake Michigan, it
is a seral dominant during succession on lake dunes [96].  In northern
Montana rough fescue (Festuca scabrella) grasslands, patches of prickly
rose, serviceberry (Amelanchier alnifolia), and snowberry
(Symphoricarpos spp.) appear to originate when rodents throw up bare
soil on which the shrubs may establish [46].  Along the eastern slopes
of the Rocky Mountains, it invades on patches of mineral soil exposed by
disturbance and pioneers on gravel bars along rivers or after fire [90].
Along rivers in British Columbia and Alaska, it first establishes with
pioneering willows and replaces them after they are overtopped by
cottonwoods on exposed gravel and silt bars [26,76,78,81].

Following disturbance on black spruce sites, prickly rose may appear as
sprouts on the freshly disturbed or burned site.  It can spread rapidly
by stem and root shoots and reaches greatest density during the tall
shrub-sapling stage or under seral aspen.  It decreases as the canopy
closes [22,25,82].  In white spruce stands, prickly rose sprouts
following disturbance, becoming a seral dominant under various mixtures
of aspen, birch, lodgepole pine, and white spruce.  Finally, it is an
understory dominant in the climax stand [22,54,61].  In British
Columbia's interior cedar-hemlock transitional subzone, it is found in
seral shrub communities with aspen, paper birch, and lodgepole pine
[29].


SEASONAL DEVELOPMENT : 
In New England, prickly rose blooms in mid-June [69].  In northwest
Illinois, the normal bloom period is during the last 2 weeks in May, and
fruit is set by July [66].  In Alaska, prickly rose blooms in June and
July, and hips turn red in August [84].

Related categories for Species: Rosa acicularis | Prickly Rose