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Jubata Grass (Cortaderia jubata)

Grass Family (Poaceae)

Cortaderia jubata (jubata grass). Photo courtesy of John M. Randall, The Nature Conservancy, Bugwood.org
Photo: John M. Randall, The Nature Conservancy, Bugwood.org

       Cortaderia jubata (jubata grass).  Photo by BLM      
Photo: BLM

Cortaderia jubata (jubata grass) - John M. Randall, The Nature Conservancy, Bugwood.org
Photo: John M. Randall, The Nature Conservancy, Bugwood.org

Description/Habitat:  Jubata grass (Cortaderia jubata) is large, perennial tussock grass that is native to South America. Jubata grass was introduced as a landscape ornamental and for erosion control, but it has since escaped cultivation and become a noxious weed in some areas of California.It is a substantial threat to the ecological quality of preserves, particularly in coastal and grassland sites. Jubata grass grows vigorously in disturbed areas, nearly any soil, under low or high moisture regimes, and in full sun or dense shade.
Similar species: Pampas grass (Cortaderia selloana) is easily confused with jubata grass (C. jubata). The two species are distinguished by stem height, leaves, plume, spikelet color, florets, leaf tip, and the presence of viable seed. Fountain-like tussocks of pampas grass are more erect, narrow, and are pale pink to silvery white in color, as compared to the showy plumes of jubata grass, which tends to be pink to violet in color.
Leaves:  Most of the leaves emerge near the base (tuft) with narrow, attenuated blades. The leaf blades are 2-10 cm wide, deep green; and the upper surface is hairy at the base. Leaves are very tough and sharp, with razor-like margins.
Flowers:  The flower clusters (panicles) are large, terminal, and plume-like, and range from 0.3 to 1 m long. Flower stems rise up to three times higher than the clump of foliage. Distinctive features of jubata grass are huge, nodding pinkish or purplish flower plumes that later turn creamy white.
Seeds:  Jubata grass possesses a breeding system termed “agamospermous apomixes” which allows plants to produce seeds without fertilization (asexual), despite the fact that all of the plants are female. The seeds can disperse long distances by human activities and by wind up to 30 km away. Each seed-bearing plume can produce up to 100,000 seeds. Seeds do not appear to survive long in the soil, although no detailed studies have yet been conducted.
Flowering Period:  Late July to September. Jubata grass can flower twice during the same season.

Management:  Jubata grass first moves into disturbed sites and can spread within a few years to form dense infestations. Once established it will also move into gaps in the surrounding native vegetation, further expanding its range. At one time there were long lines of jubata along roads within the Fort Ord National Monument range areas but those sites have now been controlled. Sometimes single plants will become established in sites of natural disturbance surrounded by native vegetation within the range areas. It is not possible to push through the vegetation to treat these plants because of concerns about unexploded ordnance.

In areas outside of the Army ranges small or medium sized jubata are hand pulled or removed with a Pulaski. The few large plants that are discovered are also often removed in this manner but it is hard, time consuming work.

Because of the risk of unexploded ordnances within the Army ranges, chemical control of jubata grass is the required and safe alternative. Large and small infestations of jubata grass can be controlled by spot treatment with a post-emergence application of glyphosate herbicide. Fall applications have been shown to result in better control than summer applications. This is due to the fact that during the fall, nutrients are being pulled down into the plant to be stored as energy reserves. However, due to the large amounts of jubata present on Army lands, treatment is done throughout the year and has been successful in controlling infestations that formerly covered many acres.


DiTomaso, J. M. and E. A. Healy. 2007. Weeds of California and Other Western States. Volume 2: Geraniaceae to Zygophyllaceae. University of California Department of Agriculture and Natural Resources: 1090-1096

DiTomaso, J. M. 2000. Cortaderia jubata. Pp. 124-128. in Bossard, C. C., J.M. Randall, and M. C. Hoshovsky. Invasive Plants of California's Wildlands. University of California Press. Berkeley, CA

Last updated: 08-20-2012