BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Prunus americana | American Plum 



GENERAL BOTANICAL CHARACTERISTICS : 
American plum is a native, deciduous, sometimes thicket-forming, erect
shrub or small tree.  The growth habit of this species can vary
considerably; plants range from shrubs approximately 3 feet (1 m) in
height to arborescent individuals growing up to 32.8 feet (10 m) [12].
On the Great Plains this species typically grows from 9.8 to 26.2 feet
(3 to 8 m) tall and is rarely treelike [9].  In Utah, American plum
forms thickets reaching heights of up to 16.4 feet (5 m), and treelike
individuals are uncommon [34].  The leaves are somewhat stout with
pubescent, usually glandless petioles; twigs often become somewhat
spinelike at the tips.  White flowers usually appear before the leaves
and are borne in fasicles of two to five on the tip of spur branchlets
or from axillary buds formed the previous season.  Fruits are yellow to
red plums (drupes), at least 0.8 inch (2 cm) long with yellow flesh and
a compressed stone.  Although this species sometimes produces small,
hard plums, the fruits are generally fleshy and highly palatable.
Occassionally trees cultivated for plums escape and persist.
Horticultural varieties can be distinguished from the native species by
their larger petals, smaller flower clusters (one to three per node),
and sometimes by the gland-tipped teeth of the leaves.


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
American plum regenerates sexually and vegetatively.  Although
regenerative strategies have not been widely documented, vegetative
expansion via rhizome initiation is apparently the primary mode of
regeneration.  This shrub typically forms thickets and colonies in the
western portion of its distribution [9,12,34].

The fruit of American plum is a yellow to red drupe containing a
compressed stone.  Seeds are approximately 0.6 to 0.7 inch (1.5 to 1.8
cm) long and 0.4 to 0.5 inch (1 to 1.2 cm) wide.  As with all species
within the Prunus genus, seed dormancy is a problem.  In order to
overcome dormancy, seeds must be exposed to an afterripening period in
the presence of oxygen and moisture [9].  Germination is usually
enhanced following cool, moist stratification for 90 to 150 days at 50
degrees F (10 degrees C); germinative capacity is approximately 60
percent following stratification at 50 degrees F (10 degrees C) for 60
days.  Germination requirements appear to vary geographically.  American
plum seed from northern Minnesota germinated much better at 50 degrees F
(10 degrees C) than at higher temperatures; whereas optimal germinating
temperatures for seeds from Nebraska are from 70 to 80 degrees F (21.1
to 26.6 degrees C) [39].  Seedbed characteristics are virtually
unstudied in this species.  Although the majority of seeds are presumed
to be deposited beneath the parent plant, frugivorous mammals probably
function as long-distance dispersal vectors.  Rogers and Applegate [26]
speculated that black bears are one of only a few disperal agents for
large-seeded species such as American plum.


SITE CHARACTERISTICS : 
In the western portion of its range, American plum is locally
distributed on moist to dry sites ranging from the plains to lower
elevations in the mountains [12].  Although commonly associated with
riparian areas, this species also occupies open to wooded locations such
as prairie ravines, pastures, roadsides, fencerows, ditchbanks, and
natural drainage patterns [9].  Soils on most sites consist of sandy to
rich loams, but plants are also somewhat tolerant of saline soils in the
West [4].

 Elevational ranges for several western states is as follows [4]:

	from 4,600 to 7,500 ft (1,402 to 2,287 m) in UT
             3,500 to 6,000 ft (1,067 to 1,829 m) in CO
             3,500 to 4,500 ft (1,067 to 1,372 m) in WY


SUCCESSIONAL STATUS : 
NO-ENTRY


SEASONAL DEVELOPMENT : 
American plum typically blooms from April to May in the Pacific
Northwest [12] and on the Great Plains [9].  Flowers characteristically
appear before the leaves and are borne in fasicles of two to five on the
tip of spur branchlets or from axillary buds formed the previous season.
Seed matures from September and October in Utah [24].

Flowering data from some western states are presented below [4,7]:

State             Earliest flowering date             Latest flowering date

CO                       April                               May
MT                       May                                 May
ND                       April                               May
UT                       May                                 June

Related categories for Species: Prunus americana | American Plum