Facts about Orchard Grass – Dactylis glomerata

Plant Description

Orchard grass is a coarse, clump-forming, cool-season, tall growing, perennial grass that normally grows about 1.4 to 4 feet (0.5-1.2 m) tall. The plant is found growing in grass and heath land, forests, riparian habitats, freshwater wetlands, coastal areas, meadows, pastures, sand dunes, disturbed sites, roadsides, rough grassland, fields, savannas, woodland borders, orchards, thickets, fence rows, powerline clearances in wooded areas and miscellaneous waste area. The plant performs well on different textured soils ranging from clay to gravely loams and on shallow to deep soils. It does not grow well in saline soils and areas with high water tables. The plants have extensive fibrous root system but no stolons and rarely have short rhizomes. Stems are flattened and are either erect or bend abruptly at the base. Culms are light green, terete, and glabrous; later they become straw-colored.

Leaves

The leaves of both fertile and infertile shoots have a similar appearance. Their blades can be 3 to 12 inches long (or more) and 1/8 to 1/3 inch wide. They are light green to dark blue-green and hairless somewhat rough on the upper and lower surfaces and margins, and sharply folded (V-shaped in cross-section). The leaf blades of infertile shoots spread outward and remain low, while the blades of alternate leaves on fertile shoots are more arching. Leaf sheaths are light green, hairless, and open toward their apices and have longitudinal veins. The ligule (projection inside on the top of the sheath) is membranous, finely toothed, rounded to pointed and relatively long (1/6 to 1/3 inch long). Auricles (appendages at the top of the sheath) are absent.

Flower

The inflorescence consists of a panicle of spikelets; the branching pattern of this panicle tends to occur along a 2-dimensional plane. The panicle is up to 10 inches long and 5 inches across, consisting of an erect rachis and short lateral branches (only 1 lateral branch per node). Latter are stiff, straight, spreading to nearly erect, and few in number. Lateral branches have dense tufts of spikelets toward their tips, otherwise they are naked. The rachis also terminates in dense tufts of spikelets.

Each spikelet consists of a dense tuft of 3-7 lemmas and their perfect florets; there is a pair of sterile glumes at the bottom. The spikelets are whitish green while their florets are blooming, but they later become light tan to brown. The glumes are linear-lanceolate, keeled, and unequal in size; the shorter glume of a pair is about 4-5 mm. in length, while the longer glume is about 5-6 mm. in length. The lemmas are linear-lanceolate and ciliate along their keels; they are about 5-8 mm. in length. In each spikelet, the upper lemmas tend to be shorter than the lower lemmas. Each floret has a pair of white plumose stigmata and 3 stamens with large white anthers. The blooming period occurs from June to September, lasting about 1-2 weeks for a colony of plants.

Fruit

The seed head is dense and spike-like in appearance when it first emerges. With maturity, it becomes open and branched. Seeds are very small, narrow, pointed about 1/3 inch long with 95,000 to 1,300,000 seeds/kg. They are food sources for caterpillars like the gatekeeper and meadow brown; while the seeds are eaten by finches and gamebirds.

Prevention and Control

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product’s label.

Physical/Mechanical Control

Beddows (1959) says that D. glomerata can easily be controlled by ploughing, and that it does not survive heavy trampling by livestock. Muyt (2001) says that plants can be dug out but that the crown must be removed to prevent regrowth. Where plants are in seed he suggests cutting and bagging the stems before removing the rest of the plant. Muyt (2001) also says that stands can be slashed regularly during the main growing season to limit seed production. When a weed in turfgrass it can eventually be eliminated by close mowing (Hathaway et al., 2004).

Biological Control

Although a few insect species seem to be confined to D. glomerata (Beddows, 1959) there has never been any interest in using any of these for biological control: the species is so-long established and so valuable in many places that this would be impractical.

Chemical Control

Muyt (2001) says that plants can be treated with non-selective herbicides like glyphosate or grass-selective herbicides like fluazifop-butyl, but follow-up treatment is needed to control seedlings and surviving plants.

Few Important Facts

• Having a deep root system, the plant is also useful for checking soil erosion.
• The plant can be grown for biomass, annual productivity ranges from 2 to 37 tons per hectare.
• It is widely used as a pasture grass and also to improve forage production on rangelands.
• Orchard grass has 487,000 seeds per pound.

References:

https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=193446#null

http://www.hear.org/pier/species/dactylis_glomerata.htm

https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomydetail?id=13114

https://pfaf.org/user/plant.aspx?latinname=Dactylis+glomerata

http://www.floracatalana.net/dactylis-glomerata-l-

https://www.cabi.org/isc/datasheet/17618

https://plants.usda.gov/core/profile?symbol=DAGL

https://en.wikipedia.org/wiki/Dactylis_glomerata

https://www.cal-ipc.org/plants/profile/dactylis-glomerata-profile/

http://www.theplantlist.org/tpl1.1/record/kew-406640

https://www.fs.fed.us/database/feis/plants/graminoid/dacglo/all.html

https://gd.eppo.int/taxon/DACGL

https://www.hort.purdue.edu/newcrop/duke_energy/Dactylis_glomerata.html

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