San Benito County Weed Management Area

Identifying and Controlling Weed Species

Before any type of control on weeds can be done, it is very important to first identify the plant.  Is it truly a weed?  (Noxious weeds are those species of plants that are detrimental or destructive to native species, agriculture, or the environment.)  Is it a beneficial native plant?  How does it reproduce?  These are important questions to answer.  Knowing how the plant reproduces will help determine how to control it.  If the plant reproduces from the roots, then just cutting the above ground portion will not control the plant.  It will only stimulate the plant to grow.  If it reproduces from seeds, when do the seeds mature?  Cutting the plant after it has gone to seed will have no long term effect on the population of that weed.  You want to remove the plant before it can add to the seed bank.  When the weed is removed it has to be replaced with something else or it could repopulate the area.  Replacing it with native plants benefits humans and the habitat.  Native plants are adapted to their environments and require the least amount of care to survive.

The table below lists all the species in the "Selected Invasive Weeds of San Benito County" booklet.  (Limited copies of this booklet are available free to San Benito County residents, contact the County Ag. Commissioner's office for a copy.)  Some have a link from this site to sites with more identification and control information.   Links will be added and changed over time.  Click on the species name for local information, then on the picture for additional identification and control information.

For information on how to calibrate your chemical sprayer click HERE.
 

Yellow Starthistle is native to southern Europe.  It invades various soil types on waste areas, roadsides, pastures, and dry rangelands.  It is toxic to horses and causes "chewing disease".

It is prevalent in San Benito County but does not occupy all potential habitats at this time. 

For information on controlling Yellow Starthistle click HERE.




Purple Starthistle is native to southern Europe.  Found in fields, roadsides, disturbed open sties, grasslands, overgrazed rangelands, and logged areas.  Plants seldom persist in shaded places and colonize most soil types that have been disturbed.

Currently found in the Northwest portion of San Benito County.



Puncturevine is native to the Mediterranean.  Grows in pastures, cultivated fields, waste areas, and disturbed sites such as roadways.  It is toxic to livestock.  It particularly thrives in sandy and sandy loam soils.  The hard spiny burs damage wool and may be injurious to livestock, as well as bare feet, dogs' pads, and bike tires.  Other common names include goathead, caltrop, and Mexican or Texas sandbur.

Puncturevine is found in disturbed soils throughout San Benito County.

Giant Reed is native to the Mediterranean.  It can grow in a wide range of conditions, from moist well-drained soils to those with a water table at or near the surface.  It is found along roadsides, in ditches, and along banks of streams and rivers.

In San Benito County it is found in riparian and watershed drainage's.  As yet it is sparsely disturbed throughout the county.

For information on controlling Giant Reed click HERE
 

Scotch Broom is native to Europe and North Africa.  It is found in soils with pH less than 6.5, low fertility, and is rare on limestone.  Inhabits disturbed places including road cuts, forest clear cuts, and riverbanks, as well as grasslands and open canopy forests.

Found in northwestern San Benito County and contiguous coastal counties.





French Broom is native to the Mediterranean.  It is found in varied soils including soils with high pH and soil with poor nutrients.  Inhabits disturbed places including road cuts, forest clear cuts, and riverbanks, as well as grasslands and open canopy forests.

Found in northwestern San Benito County and contiguous coastal counties.

Medusahead is native to Eurasia.  Appears most commonly on high shrink-swell clay soils.  Infested rangelands have   suffered up to 75% reductions in grazing capacity. 

Infested areas have been found throughout San Benito County.

For information on controlling Medusahead click HERE

Hoary Cress is native to Europe.  Commonly grows in disturbed sites, saline soils, and along riverbanks and other waterways.

Hoary Cress, also locally known as Hellweed, occurs throughout San Benito County. 
(Photo from CALFLORA.)

For information on controlling Hoary Cress click HERE





Saltcedar (also known as Tamarisk) is native to Eurasia and Africa.  It establishes in disturbed and undisturbed streams, waterways, bottomlands, banks and drainage washes of natural or artificial water bodies, moist rangelands and pastures, and other areas where seedlings can be exposed to extended periods of saturated soil for establishment.  Can grow on highly saline soils and tolerates alkali conditions, significantly lowers water table and reduces water quality.

It is currently found in riparian areas and watersheds throughout San Benito County.  Commonly used for horticulture but escapes and spreads quickly.

Italian Thistle is native to the Mediterranean, southern Europe, and North Africa to Pakistan.  Introduced into the U.S. around 1912, spread by wind, vehicles, and animals, a single plant can produce up to 20,000 seeds per season.

Occurs throughout CA coastal ranges, including San Benito County, below 3,000 ft. in meadows, pastures, ranges, on roadsides, and in disturbed wildland areas.

For information on controlling Italian Thistle click HERE.




Tree-of-Heaven is native to Asia.  Although it is usually found in disturbed areas, it does spread to undisturbed areas and does well on very poor soils.

Currently found throughout San Benito County and was originally used for horticulture.

 For information on controlling Tree-of-Heaven click HERE.