Smooth Brome (Invasive Exotic Plants of North Carolina)

Smooth Brome

Bromus inermis

Summary ¹⁰

Bromus inermis is a species of the true grass family (Poaceae). This bunchgrass is native to Europe.

Management considerations ¹¹

More info for the terms: cool-season, fire exclusion, forbs, prescribed fire, restoration, rhizome

Range: Smooth brome's tolerance to grazing is generally rated as high
[56]. It is highly adaptable, having persisted in many of the habitats
where it was planted to increase forage production including
pinyon-juniper (Pinus-Juniperus spp.) [39], quaking aspen (Populus
tremuloides) [21], and subalpine and alpine ranges [56,102]. It has
persisted on old saltgrass (Distichlis spicata) meadows with saline
soils once the saltgrass was removed [84,85].

Smooth brome may not tolerate grazing on all habitat or site types.
Currie and Smith [36] reported that smooth brome planted on
low-fertility ponderosa pine (Pinus ponderosa) forest soils in Colorado
declined under even light-intensity cattle grazing. They speculated
that smooth brome is more likely to persist under cattle grazing on
fertile soils.

Laycock and Conrad [77] used cattle to test several grazing systems on
rangeland seeded to crested wheatgrasses (Agropyron cristatum and A.
desertorum) and smooth brome in mountain big sagebrush (Artemisia
tridentata spp. vaseyana) habitat in Utah. They found that average
cattle weight gain was the same under all systems, but heavy June
grazing in alternate years best promoted grass production.

Ungulates in Yellowstone National Park utilized smooth brome growing in
association with other graminoids and forbs, but did not graze smooth
brome where it grew in a monoculture [48].

Forestry: In British Columbia, height and biomass of lodgepole pine
(Pinus contorta var. latifolia) seedlings established from a mix of
lodgepole pine seed and smooth brome and other grass seed were less
than height and biomass of lodgepole pine seedlings established from
lodgepole pine seed sown alone [28].

Native grassland restoration: Smooth brome dominates many native
grasslands and old fields [2]. Masters and Vogel [82] stated that on
tallgrass prairie, it is usually found in areas with a history of
overgrazing and/or fire exclusion. Grassland restoration efforts often
include controlling smooth brome with cool-season grass herbicides such
as atrazine and glyphosate, mowing, and/or prescribed fire [73].

Anderson [2] found that near Lincoln, Nebraska, fall application of
glyphosate helped control smooth brome. Atrazine may not be as
effective; other studies [83,96] have reported that while atrazine
controlled other exotic cool-season grasses, it did not significantly
reduce smooth brome.

Establishment and maintenance: Seed handling and planting guidelines
for smooth brome are available [49,116,117]. Cultivars adapted to
selected environments and/or regions are sold commercially
[56,103,104,108,119,123].

Smooth brome requires fertile soil in order to maintain nutritional
quality. On infertile soils it needs periodic fertilization or a
companion nitrogen fixer. On rangelands smooth brome is usually planted
in a mix with alfalfa (Medicago sativa), yellow sweet clover (Melilotus
officinalis), or other legume species. Fertilization affects growth
allocation: Watkins [120] found that fertilizers increased leaf and
shoot growth but reduced rhizome and root growth.

Rhizomatous cultivars become sod-bound after several years unless litter
is removed by grazing and/or fire [56,110].

Weediness ¹²

This plant may become weedy or invasive in some regions or habitats and may displace desirable vegetation if not properly managed. Please consult with your local NRCS Field Office, Cooperative Extension Service office, or state natural resource or agriculture department regarding its status and use. Weed information is also available from the PLANTS Web site at plants.usda.gov.

Establishment ¹³

A clean firm seedbed is needed. Due to the slow germination and establishment of smooth brome, spring seedings are especially preferred in the northern states. In southern areas, late summer seedings are a second option. Fall seedings should be made at least 6 weeks before a killing frost is expected. Seeding rates are typically 5-10 pounds per acre in mixtures, and about 15 pounds when seeded alone. When smooth brome is seeded in a mixture with alfalfa, the alternate row method will give the best results. For seed production plantings under irrigation, seed in rows 30 to 42 inches apart at a rate of 3 to 4 pounds per acre. Seedings should be drilled at a depth of 1/2 to 3/4 inch. If broadcast increase the seeding rate and cultipack after planting.

Sources and Credits

(c) Hörður Kristinsson, some rights reserved (CC BY-NC), http://www.flickr.com/photos/30548850@N08/4840475673
(c) James K. Lindsey, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:Bromus.inermis.jpg
(c) Christian Fischer, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:BromusInermisFlowering.jpg
(c) Matt Lavin, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:Bromus_inermis_(3731514115).jpg
(c) Matt Lavin, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:Bromus_inermis_(3731515013).jpg
(c) Matt Lavin, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:Bromus_inermis_(3738506011).jpg
(c) Matt Lavin, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:Bromus_inermis_(3739398258).jpg
(c) Matt Lavin, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:Bromus_inermis_(3860383107).jpg
(c) Matt Lavin, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:Bromus_inermis_(3861164554).jpg
Adapted by Kate Wagner from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Bromus_inermis
Public Domain, http://eol.org/data_objects/24631153
Public Domain, http://eol.org/data_objects/1379229
Public Domain, http://eol.org/data_objects/1379232

More Info

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Smooth Brome

Summary 10

Management considerations 11

Weediness 12

Establishment 13