BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Physocarpus malvaceus | Ninebark 



GENERAL BOTANICAL CHARACTERISTICS : 
This deciduous shrub is generally 2.0 to 7.0 feet (0.6-2.1 m) tall;
broad stem structure; twigs glabrous; bark shreddy on older branchlets;
inflorescence corymbose [21].  The fruit is an inflated two- to
three-chambered capsule with two to four very small seeds per chamber.
Ninebark leaves are palmately three- to five-lobed, and begin to turn
color as early as late July, becoming brownish-red by early autumn [23].

Ninebark has a horizontal perennating root system, although it is often
called a "rootcrown shrub".  Sectioning revealed that its perennating
organ is a rhizome [3].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Seeds, flowering, and fruiting:  Flowering dates vary from May to July,
and fruit ripening occurs between late August and early October.
Ninebark averaged 756,000 cleaned seeds per pound (344,000/kg), with a
16 percent soundness value [16].  Ninebark seeds are primarily
transported by gravity.  Seeds stored in the soil are 11 percent viable,
and germinate in partial shade on scarified soil [46].

Regeneration following disturbance:  In western Montana, Bradley [4]
found ninebark to occur in two forms:  singularly or in small clumps of
stems sprouting from one rhizome; or in large groupings with many stems
originating from a number of interlaced rhizomes.  External observations
of rhizomes revealed numerous suppressed buds along the entire length of
the axis.  One half of the shrubs excavated had stems arising from more
than one section of the rhizome.  Presence of buds throughout the
rhizome may permit sprouting at many points given the proper
environmental conditions [4].


SITE CHARACTERISTICS : 
Ninebark is most commonly found on hillsides, canyons, and grasslands on
mesic ponderosa pine and Douglas-fir sites [17,23].  It also has been
found on moist slopes and streamsides in mountain-brush, aspen, and
mixed-conifer woodlands at 5,250 to 10,000 feet (1,600-3,000 m)
elevation [37].

Soils:  Ninebark is found predominantly on soils with no exposed rocks.
Parent materials range from calcareous/noncalcareous sedimentary rocks
such as limestone, sandstone, and conglomerates, to igneous rock such as
granites and basalts.  Soil textures found on ninebark sites range from
sandy loams to silty clay loams.  Ash layers have been found on some
loess soils in central Idaho.  Surface soil acidity range from pH 5.5 to
7.1.  The average duff layer is 2.6 inches (6.5 cm) with an effective
rooting depth generally at 15 inches (38 cm) [8,40,47].


SUCCESSIONAL STATUS : 
Ninebark is associated with a variety of species through its
successional progression.  In early seral stages, ninebark is a part of
communities that reflect great species diversity.  This would include
overstory species such as quaking aspen (Populus tremuloides), shrub
species like redstem ceanothus (Ceanothus velutinus), and numerous
herbaceous species.  In mid-seral communities ninebark is associated
mostly with ponderosa pine and Douglas-fir, shrubs in the Salix and
Prunus genera, and herbs such as penstemon (Penstemon attenuatus) and
Fragaria species.  In climax ninebark associations, Douglas-fir is the
dominant overstory species and occurs in pure stands.  Shrub layers
become increasingly simple, consisting primarily of Physocarpus,
Symphoricarpus, Amelanchier, and Spiraea.  The herbaceus layer decreases
and is generally limited to shade-tolerant rhizomatous species [46].

In the Intermountain West, ninebark forms a union primarily in the
Douglas-fir/ninebark association.  In northern Idaho, this association
is generally found between the drier ponderosa pine/Idaho fescue
(Festuca idahoensis) or ponderosa pine/ninebark associations, and the
moister grand fir/mountain lover (Pachistima myrsinites) association
[6].

Ninebark responds to various forms of disturbance such as silvicultural
cutting or wildfire by major vegetative responses.  This includes an
increase in coverage from existing plants and vigorous rhizome sprouting
[46].  Ninebark is an obligate pioneer species that predictably
increases rapidly in average height following disturbance.  Over time,
as overstory competition increases, the height of ninebark generally
decreases [24].


SEASONAL DEVELOPMENT : 
Ninebark flowering and fruiting dates are as follows [16]:

                             Flowering    Fruit Ripening   Seed Dispersal
     Site        Elevation     Dates           Dates           Dates
---------------  ---------   ---------    --------------   --------------
Kootenai Co. ID   3200 ft    5/20 - 6/30      August        Sept. 15 +
Missoula Co. MT   3200 ft     5/30 - 6/25    8/20 - 9/5      Oct.  10 + 
                  4400 ft     6/20 - 7/10    8/20 - 9/25     Oct.  5 +
                  5400 ft     6/25 - 7/15    8/20 - 9/30     Oct.  5 + 
                  6400 ft     7/5  - 7/25    9/5  - 9/25     Oct.  10 +

Ninebark shrubs in northern Idaho showed stem elongation 25 days earlier
on southern aspects than on the cooler eastern aspects.  From this, it
is hypothesized that stem elongation may be controlled by air
temperature [11].  

Seasonal development for ninebark east of the Continental Divide in
Montana and Yellowstone National Park from 1928 to 1937 are as follows
[43]:

                     Average    Earliest    Latest  Standard  Number of
                      Date        Date       Date    Error    Observations

First Appearance     May  3      Apr   6    May  20    2          23
Leaves Full Grown    June 18     May  17    July 20    3          23
Flowers Start        June 13     May  22    June 30    2          24
Flowers End          July 6      June 18    July 21    2          24
Fruits Ripe          Aug  4      June 16    Sept  9    4          24
Seed Fall Starts     Aug  17     July 26    Sept 18   16           3
Leaves Wither        Aug  9      July  1    Sept 19    3          24
Leaves Fallen        Aug  24     July 23    Sept 26    3          24
First Frost Injury   Sept 25     Aug  28    Oct  26    3          24

Major phenological activities of ninebark in northern Idaho are as
follows [36]:

        Bud     Leafing     Stem                Fruit   Leaf Color  Leaf
Year   Swell      Out      Growth    Blooming   Growth   Change     Fall
------------------------------------------------------------------------
1971     NA     4/21-5/11  5/4-6/18  5/26-6/18  6/18-NA   9/23      9/23      
1972     NA     4/19-5/23  5/6-6/13  5/19-6/13  6/13-NA   9/26      9/26
1973  4/3-4/15  4/23-6/4   5/2-6/4   5/23-6/12  6/19-NA   8/28      10/2

Related categories for Species: Physocarpus malvaceus | Ninebark