Yes, we have herbicide

If there was ever an indication that restoring natural areas is really horticulture, this is it. Even an artisanal project like ours would never be able to keep up with noxious weed growth and re-growth without a certain amount of pesticide application.

There is a difference between widely broadcasting pesticides that kill a lot of organisms and applying a small amount to a specific target at the right time in its life cycle. This is the time that my current target – scotch broom – is most vulnerable. And if there is poison oak adjacent, well, I might spend some time on that.

The two herbicides I use – glyphosate on(ingredient in Roundup®) and triclopyr (Garlon®) are the least toxic to me, and the assortment of creatures they’re likely to contact. (I prefer to use the ester formulation of Garlon because it is less poisonous to me, the applicator, than the amine). I occasionally use Poast®, an herbicide that kills grass but not broadleaf weeds.

Restorationists rely on spraying weeds to get native plants established. But they also are looking out for some of the organisms that can be damaged by overzealous use of chemicals. There is a growing conservation biology literature, for example, on pesticide effects on rare and endangered butterflies and their larvae.

Anyway, there are other ways to work on the weeds. One hand-weeding method developed by Joan Bradley and her sister relied on minimal disturbance, slow clearing, and fostering natural regeneration by working from the best, most intact areas outward. This method has a lot to recommend it. It requires discipline to not clear out all the weeds in the worst areas. It requires patience. But the good thing is, it doesn’t take a lot of intensive work – the two authors regenerated 40 acres in a public park in Australia by working just a few hours at a time.

I still aspire to mastering that technique. Meanwhile, the hybrid method of following machine-clearing with hand work, mowing, and spraying will have to do. I’m off to climb the hill with my 40 pounds of solution – 24 in the backpack sprayer, carrying a jug with the rest. Saves on the gym membership.

Scotch broom showing the effects of recent Garlon 3A application

P.S. Scotch broom flowers make a pretty good yarn dye. I experiment with the many I haven’t killed yet.

In the Beginning … (before/after)

Underneath the scotch broom, Douglas fir seedlings, and poison oak, somewhere there was an oak savanna. The first thing the Conservation District did was to bring in a machine called a skid steer shear. Which pretty much does what it says. This versatile piece of equipment mowed between the trees, then cut them at ground level and stacked them into slash piles.

(See one in action here at 11:00 min and here on our property)

After the radical surgery, one more pass with the mower, and the first phase was done. Immediately after mowing it looks pretty raw, but shortly will recover with grass and wildflowers released from the overstory. The work pictured here was done in 2007.

Mower almost hidden in the old growth scotch broom

Scotch broom is a non native invasive plant, originally thought to be a good plant for erosion control. It only belongs where it is native, and that’s not here! Introductions by well-meaning people often turn out to be really bad ideas, and this one was a major ecosystem destroyer – altering soil nitrogen and competing aggressively, with a seed bank that lasts for many decades. After the mowing, constant weed control of the resprouts and seedlings will continue for years and years.

Mower with raised deck grinding small trees

Immediately after mowing ground was reseeded with native grass

The deer adopted an interested yet bemused attitude to the work