BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Dactylis glomerata | Orchardgrass 



GENERAL BOTANICAL CHARACTERISTICS : 
Orchardgrass is a cool-season, perennial bunchgrass, 1.4 to 4 feet
(0.5-1.2 m ) tall with erect, glabrous culms and blades 4 to 16 inches
(10-40 cm) long and 0.1 to 0.5 inch (0.2-1.1 cm) wide.  The
inflorescence is a panicle with two to six florets per spikelet, with
the spikelets tightly clustered on one side of the branch.  Orchardgrass
is nonrhizomatous [21].  Most root development is in the upper 3 inches
(8 cm) of soil but extends to at least 18 inches (46 cm) below the
surface [23], producing a dense sod of medium-sized roots [26].


RAUNKIAER LIFE FORM : 
   Hemicryptophyte


REGENERATION PROCESSES : 
Orchardgrass reproduces largely by seed and by tiller formation.  The
relatively large seed does not have an innate dormancy [24].  Seed can
germinate in either light or darkness; germination is largely controlled
by moisture availability, and most seed germinates in the fall.  Thus,
orchardgrass does not tend to build up seedbanks in the soil [24].


SITE CHARACTERISTICS : 
Orchardgrass is best adapted to well-drained, rich or moderately fertile
soils with an adequate water regime (12 inches or more annual
precipitation [30 cm]) [24,28,62,71] and temperatures that are not
extreme [4,28].  Optimum top growth is achieved at temperatures of
approximately 70 degrees Fahrenheit (21 deg C) [72].  Orchardgrass is
shade tolerant and does well at higher elevations in the western United
States and Canada (4,900 to 6,200 feet [1,500-1,900,m]) [28].  It is
widely planted in the eastern United States, most notably in
Pennsylvania, Maryland, and West Virginia [13].


SUCCESSIONAL STATUS : 
Facultative Seral Species

Orchardgrass is shade tolerant.  It is often seeded on disturbed areas
and is naturalized to fields, meadows, and waste places [67].  It is
long-lived but susceptible to replacement by native species, especially
in drier areas, and does not usually persist past 1 or 2 decades
[12,42,43].

Stands of orchardgrass tend to become clumpier with age, especially
under high nitrogen conditions.  This may be best explained by the
relative amounts of competition among tillers and among plants [72].


SEASONAL DEVELOPMENT : 
Orchardgrass begins growth early in spring and flowers from May to
September or October.  In dry areas it is dormant in summer, but will
add new growth in the fall, and will flower again in fall under
appropriate conditions.  Most European populations are obligately
dormant in the summer, showing no growth even when irrigated.  Some
Mediterranean populations do not have this obligate dormancy [16].  A
green basal rosette is maintained through winter [14].  Flowering
appears to be temperature rather than light dependent [20].  Seed
shattering takes place in late summer; most seed will germinate in fall
as there is no innate dormancy [24].

Related categories for Species: Dactylis glomerata | Orchardgrass