Andrew Lawrence with Khaki weed harvested from Kaimana Beach Park, Waikiki.
Photo R. Morse/A. Lawrence

Khaki Weed Control

It is easy to get frustrated with Khaki weed control. The weed seems to keep coming back, no matter how many times you pull it (or poison it.) There is, however, a sensible recipe, handed over by our Australian friends, who are well-experienced with khaki-weed control. An important ingredient in this recipe is 'perseverance'.

Here is some helpful control-strategy advise from PHIL ELSON; District Coordinator for the Animal and Plant Control Commission (APCC)-- State of South Australia:

"As you are probably aware it [khaki weed] is very easily spread particularly by footware and tyres so restricting movement and mowing hygiene are paramount in stopping or slowing its spread.

"My experience with control is if you can prevent all seed set and kill the tuber of existing plants it does not seem to persist for longer than about 3 years leading me to believe that the seed life is not too long. That of course relies on no new seed being introduced." --Phil Elson.

Short seed life is a fortunate limiting factor in the spread of Khaki weed. [My guess, from experience, is that seed life for khaki may be under 2 years. But that should not be taken as a researched fact.]

Here are some general khaki-weed-control tips, published (on line) by the Government of South Australia; APCC:

"The best control strategy is to keep khaki weed off the property.
Successful control of khaki weed involves destroying recurrent germinations after the initial control program......Continued vigilance on your property for new outbreaks is required ...The key to controlling any weed population is to prevent the plants from reproducing....Hand hoe small infestations before seeds form, ensuring all of the tap root is removed; and dispose of plants by burning. Killing the plant at the end of its season will not help you control the infestation.... "
Replacement of khaki weed with competitive pasture species [or turf] will prevent re-infestation."

See Weed Control Notes (Pdf) for the full document quoted above.

Chemical control should be exercised with caution with respect to the environment and other life forms, including aquatic and sea-life. Some 'broad-leaf' herbicides may be appropriate for khaki weed. Consult an expert in this area. The popular herbicide, Roundup, might not be appropriate for khaki weed.