Devil Weed (Chromolaena odorata)

[Durian Fiend]

I received a notice card in the mail that this plant was first found on the Big Island in 2021 and, of course, has recently been found in Puna.  

The card offers a free yard check.  "Any plants found will be removed by our specialists at no cost to you. "  BIISC-Big Island Invasive Species Committee.

Threats from the plant are:  Skin irritant, respiratory irritant, toxic to animals, promotes wildfire and an agricultural pest.  

Sounds bad alright!  Anyone have experience with this one?

[MyManao]

From.. https://dlnr.hawaii.gov/hisc/info/biocon...a-odorata/

Close up of C. odorata. Note the three prominent “pitchfork” shaped veins in leaves, giving it the name devil weed.

DEVIL WEED (CHROMOLAENA ODORATA)

• Hawaii Pacific Weed Risk Assessment: High Risk

• Chromolaena odorata, also known as devil weed, siam weed, or bitter bush, is one of the most notorious tropical weeds in the world. Emerging as a shrub that quickly forms dense thickets, it can thrive in all environments except deep shade, flourishing in newly disturbed areas. Each plant can grow up to 12 feet tall and produce 800,000 small seeds in a year, which readily disperse via the wind or burrow into clothing, gear, or fur.

• The plant suppresses the growth of other plants (it’s “allelopathic”), allowing it to grow in dense fire-prone thickets in both native forest and agricultural fields choking out all other plant life. If allowed to spread unchecked, it could easily become ubiquitous across dry to mesic-wet environments in Hawaii.

• Distribution: C. odorata was first detected in Hawai‘i at the Kahuku Training Area on the north shore of O‘ahu in January 2011.  The weed has been found in Kahana Valley, Pūpūkea, and ʻAiea on ʻOahu, and has recently been identified in Hilo and the Puna District on Hawaiʻi island. C. odorata is native to Central and South America and is a well-documented pan-global pest in the tropics worldwide.

[Midnight Rambler]

It's bad, bad, bad. It's a composite so it has tiny wind-blown seeds, and they also catch in things and spread around that way. It first showed up at the motocross area in Kahuku on Oahu, and spread around there by the dirt bikers. They tried to eradicate it but the main infestation is so dense it's impossible, and people keep going up there and spreading it around to new sites. On Big Island it first showed up at the Waiakea ATV park on Stainback so that's probably how it got here too. On other Pacific islands it's so bad in places that they've had to abandon farms because it grows so dense and is an irritant when you try to remove it.

It is kind of similar to some other weeds here that aren't so bad, but those are still weeds so it's still fine to pull them out. If you do find it, keep checking because the seeds will keep germinating for a few years.

[punikahakaiferret]

https://www.capitol.hawaii.gov/session/measure_indiv.aspx?billtype=SB&billnumber=3237&year=2024

Got this in my email from BIISC...an opportunity to submit testimony regarding invasive species, but it sure does not seem to be an easy site to navigate.

Too much to hope the folks at DOA could actually look at what plants are being brought here, any more than hoping the DEA could catch all the drugs, or that ATF could catch all the fireworks.

Forgive me for sounding cynical and nigh-hopeless.