Biology and Impacts of cheatgrass (Bromus tectorum), foxtail barley (Hordeum jubatum), and bulbous bluegrass (Poa bulbosa) Brian Sebade University of Wyoming Extension Extension Educator for Northeast Wyoming
What is a weed?
A weed is... • Plants that are competitive, persistent, and pernicious and therefore interfere with human activities –Stephen Miller
General Biology of Bromus tectorum L. • Common names: downy brome, cheatgrass, cheat • Introduced from the Mediterranean area of Europe • Believed to have reached the United States in the late 1800’s via packaging material • Historically was used extensively for thatching roofs in the Mediterranean region • Cheatgrass has the ability to establish quickly on growing sites that are undesirable to other species • Has made immediate and major impacts since its introduction
Biology continued Winter annual growth pattern Grows 4-24 inches tall in high plant densities Prefers well drained soils of most textures Not well adapted to saline or sodic soils Usually greens up before most native plant species in the early spring • Mature plants often turn a purplish color • Large amounts of seeds are produced and are notorious for sticking to objects • • • • •
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Cheatgrass Impacts • • • • • • • • •
Grazing potential affected Increased fire potential Loss of desired species Loss of desired function and structure of sites Crop yield decreases Soil nutrient changes Resources for control Others? Positive impacts? http://plants.usda.gov/gallery/standard/brte_009_shp.jpg
Biology of foxtail barley • • • • • • • •
Cool perennial growth pattern Reproduces mainly via seeds Seeds that can easily be dispersed Height 1-2 feet tall Adapted to wet soils Enjoys alkaline soils Native to North America Squirreltail is a similar species http://plants.usda.gov/gallery/standard/hoju_008_shp.jpg
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Foxtail Barley Impacts • Decreased grazing potential • Removal of desired species (i.e. monoculture stands) • Loss of site function and structure • Decreased crop yields • Harmful to livestock (injuries to eye, mouth and throats of grazing animals) • Resources for control • Others? • Benefits?
Bulbous Bluegrass Biology • Cool season perennial grass • Introduced from Europe • Grows from basal bulbs (only grass known to grow from true bulbs) • Grows to a height of 6-24 inches tall • Thought to reproduces asexually when introduced, yet sexual when growing in native regions • Most likely because of different growing conditions
Biology continued • Grows in most temperate and subtropical regions • Generally speaking bulbous bluegrass enjoys mild winters, dry summer, and winter rain • Can be found in many sites, if the site receives 12-40 inches of precipitation • Adapted to a variety of soils textures and characteristics • Attempts have been made to cultivate the grass as a turf species
Sheri Hagwood @ USDA-NRCS PLANTS Database
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Bulbous Bluegrass Impacts • • • • • •
Decreased crop yields Decreased structure and function Loss of desirable species Resources for control Others? Benefits?
Biology Overview • All three species considered weeds and exhibit weedy traits • All three species are adapted to a wide range of soil types, textures, and precipitation regimes • All three are able to quickly spread and occupy undesirable and desirable growing locations • Cool season growing patterns are used by all three species • Cheatgrass is an annual whereas bulbous bluegrass and foxtail barley are perennials • Each species has a certain niche it uses to maintain large populations in certain areas
Impacts Overview • All three species to some extent impact grazing by livestock • All three have the ability to affect the structure and function of a site • All three can decrease amount of desired plant species • All three can negatively impact crop production • All three usually require monetary, time, or energy for control when not desired
Structure and Function • Native plant community structure and function are negatively impacted with these processes: Nutrient cycling Fire regimes Water cycling Different size and structure of plant community (new structure of plant community might become less desirable for certain wildlife species)
Positive impacts • All three provide limited grazing opportunities depending on livestock species and timing of grazing • Some wildlife species might benefit form these species (example chuckers and cheatgrass)
Take Home Message • One of these species can be found in almost any region of Northeast Wyoming • Different management strategies might be needed for control of each species even though all three species exhibit weedy traits • All three species exhibit slightly different growth patterns (annual, perennial) and desired growing regimes (temperature, soil, water)
Questions
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