Ada County Weed Pest and Mosquito Abatement Ada County's 5 Worst Weeds - Puncturevine

 

***IMPORTANT NOTE***

According to Idaho Code 22-2407, Idaho property owners carry the primary burden of controlling noxious weeds on their land.  County Weed Superintendents may only treat noxious weeds on private property if the landowner fails to fully mitigate the situation.  In such instances, the County will treat the noxious weeds and bill the property owner for the weed control efforts. 

 

Puncturevine is an annual weed that reproduces solely by seed.  It begins sprouting when the soil temperature becomes high enough, usually in mid May or early June.  Depending on weather conditions, the weed's first flowers can appear within a week of germination.  A hard, spined, seed head soon develops and at maturity, breaks into five, spined seeds, commonly called "goatheads." These spiny seeds are hard and sharp enough to puncture bicycle tires or stick in the soles of pedestrians' or hikers' shoes.  Spines help the seed to be dispersed when they stick into objects and animals, and are moved to new areas. Since seeds from puncturevine plants can remain dormant in the soil for up to five years, controlling the plant becomes VERY difficult.

 
Ada County Weed Control workers use herbicides containing chlorsulfuron to control puncturevine.  Chlorsulfuron can affect the plant on contact and remains active in the soil.  The residual effect of this chemical allows seeds to germinate and absorb the herbicide through the roots, destroying the new sprouts.  In some areas and soil types, the chlorsulfuron is active for up to four months, and must be applied in the soil early enough in the spring so that rainfall pushes it to the top one-half inch of the dirt.

As chlorsulfuron degrades and puncturevine begins to appear in patches -- usually around June or July -- county Weed Control workers switch to products that contain 2,4-D, which is very effective on puncturevine.  Most farm and home supply stores carry 2,4-D, usually in combination with other herbicides that all control broad-leaved plants.  Other residual herbicides that can be effective on puncturevine, but homeowners must take extreme care when applying these products; most are not appropriate for home settings since they have a long-term effect on planting and can damage other vegetation (including trees and shrubs).

Puncturevine can germinate, grow, and begin to produce seed in as few as two weeks.  Scout for new sprouts and be prepared to reapply herbicides every two weeks throughout the summer.  This ensures no plants survive to replenish the seed supply.  With such a long seed dormancy and high survival rate, your weed control plan will need to be a long term to ensure that all viable seed is gone from the soil.

An alternative to herbicide treatments is to cut and remove the weeds, which can be difficult on large areas.   Vines more than even a few inches long can produce viable seed.

For help controlling a weed control problem, or for clarification about using herbicides, feel free to call Ada County Noxious Weed Control at (208) 577-4646, or visit our office at 975 E. Pine in Meridian. Our office hours are from 7:30 a.m. to 5 p.m. Monday through Friday except holidays.

  

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Ada County Weed Pest and Mosquito Abatement Ada County's 5 Worst Weeds - Puncturevine

 

***IMPORTANT NOTE***

According to Idaho Code 22-2407, Idaho property owners carry the primary burden of controlling noxious weeds on their land.  County Weed Superintendents may only treat noxious weeds on private property if the landowner fails to fully mitigate the situation.  In such instances, the County will treat the noxious weeds and bill the property owner for the weed control efforts. 

 

Puncturevine is an annual weed that reproduces solely by seed.  It begins sprouting when the soil temperature becomes high enough, usually in mid May or early June.  Depending on weather conditions, the weed's first flowers can appear within a week of germination.  A hard, spined, seed head soon develops and at maturity, breaks into five, spined seeds, commonly called "goatheads." These spiny seeds are hard and sharp enough to puncture bicycle tires or stick in the soles of pedestrians' or hikers' shoes.  Spines help the seed to be dispersed when they stick into objects and animals, and are moved to new areas. Since seeds from puncturevine plants can remain dormant in the soil for up to five years, controlling the plant becomes VERY difficult.

 
Ada County Weed Control workers use herbicides containing chlorsulfuron to control puncturevine.  Chlorsulfuron can affect the plant on contact and remains active in the soil.  The residual effect of this chemical allows seeds to germinate and absorb the herbicide through the roots, destroying the new sprouts.  In some areas and soil types, the chlorsulfuron is active for up to four months, and must be applied in the soil early enough in the spring so that rainfall pushes it to the top one-half inch of the dirt.

As chlorsulfuron degrades and puncturevine begins to appear in patches -- usually around June or July -- county Weed Control workers switch to products that contain 2,4-D, which is very effective on puncturevine.  Most farm and home supply stores carry 2,4-D, usually in combination with other herbicides that all control broad-leaved plants.  Other residual herbicides that can be effective on puncturevine, but homeowners must take extreme care when applying these products; most are not appropriate for home settings since they have a long-term effect on planting and can damage other vegetation (including trees and shrubs).

Puncturevine can germinate, grow, and begin to produce seed in as few as two weeks.  Scout for new sprouts and be prepared to reapply herbicides every two weeks throughout the summer.  This ensures no plants survive to replenish the seed supply.  With such a long seed dormancy and high survival rate, your weed control plan will need to be a long term to ensure that all viable seed is gone from the soil.

An alternative to herbicide treatments is to cut and remove the weeds, which can be difficult on large areas.   Vines more than even a few inches long can produce viable seed.

For help controlling a weed control problem, or for clarification about using herbicides, feel free to call Ada County Noxious Weed Control at (208) 577-4646, or visit our office at 975 E. Pine in Meridian. Our office hours are from 7:30 a.m. to 5 p.m. Monday through Friday except holidays.

  

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