De-lovely, De-weeds & D-limonene

A couple of weeks ago I happened to be wandering the “organic” aisle of my local hardware store, as I do every now and then to see what’s been added to the store’s inventory. In the past 6 years I’ve watched this section grow from one or two products to more than a dozen different ones filling half the length of the aisle, which I’d say is an indication of consumer demand. And on this most recent perusal I found something I’d never seen before: “organic” weed killer based on D-limonene, a citrus oil extracted from the rinds of oranges.

I’ve used other natural, earth-friendly limonene-based products: adhesive remover/solvent/degreaser, household cleaner, ant killer. Sounds like powerful stuff, doesn’t it? Since it’s OMRI-listed, of course it’ll be killing those weeds softly, shouldn’t it? However, if something says it’s “worryfree” I start getting skeptical. Is it safe, and does it work – really? I had to try it.

I usually pull weeds by hand or use a propane flamer to burn them. So a 32 oz bottle of concentrate for $21.99 nearly took my breath away – this is not cheap stuff, but then it wasn’t locked up like the Roundup was. On the way home I stopped to visit a friend. When I got back to my truck and opened the door, my sinuses were blasted with a familiar odor from small-kid time: Lemon Pledge. An oily scent, not entirely beckoning, like a crateful of Meyers with an industrial undertone. Apparently the bottle tipped, and even though the cashier had tightened it, it leaked into the plastic bag and a tiny bit spilled on the floor mat. Even a week later, each time my visiting niece got into my truck, she’d inhale deeply and sigh, “Mmm, auntie, your car smells so nice.” Not your typical reaction, but keep it out of reach of children anyway – read the label, there are some warnings.

The label says this weed killer takes care of “annual weeds” and that “perennial weeds may need more than one treatment.” I’m not sure what annual weeds are in Hawai'i though, since many plants perennialize here. When I bought the weed killer I did not know that even though it is a concentrate, 32 oz makes only 1 gallon of spray! I’ve decided that if this 70% D-limonene pesticide proves to be effective I’m going to use it only in areas next to the house where I don’t want to use flame.

Have a look at some of the weeds I’m trying it on.

(Warning: the following pictures may be disturbing to those with obsessive tendencies.)

garden spurge, koko kahiki, Chamaesyce hirta

Phyllanthus amarus

partridge pea; lauiki, Chamaecrista nictitans

bubble gum plant; root beer plant, Polygala paniculata

buttonweed (Spermacoce assurgens)

...plus oxalis and some assorted grasses and sedges.

Stay tuned for the results in the next couple of weeks!