I'd worry about bits of it maybe being enough to generate plants. I understand that they can be very invasive.

Jeri

That's a good question and I don't know what they do in tropical climates, but I have quite a bit of experience weeding out Equisetum arvense from my old garden (which started as a sandy bog land, very acidic and wet). I would not call it an aggressive weed, the roots stay, but the growth back is rather moderate, nowhere near as bad as the dandelions. They also sort of go away themselves when the soil gets drained and made less acidic. I would doubt that they would self seed in rose beds that much, at least in my old garden they were still growing wild in the woods 100 meters away and we haven't had them in our garden ever since we improved the drainage.

I guess they may be declared invasive weeds by the farmers because that's something they can't really kill with herbicides. I can imagine it can be chemical farmers nightmare then.

In a compost tea/brew all parts of the plant are dead. There's no chance it will sprout from bits and pieces. The best horsetail is picked before the seed part on top of the plant appear, and it's easily avoided. I use it, and it has a strenghtening effect on the roses. I spray with it after a day or too, before it gets smelly, after that I water it down into the soil. When you pick horsetail you never get the roots any way, only parts above. It's not like ground elder, but it is a hard weed to get rid of when it first has had the chance established. I have used it for years and it has never appeared in my garden. I have to go for a good 30 minute walk to pick it, and I have used it after the seed part appears too.

elemire,

I am interested in your results with this tea. Please keep us posted.

Veronica

Equisetum is declared a noxious plant in Oregon, and it's pretty invasive in my yard, where it's coming up from a creek ravine behind my house. It's not as problematic as, say, the dratted cottonwood or sumac trees, but it's a nonstop project to keep them pulled. The roses are farther from the ravine (because of shade, not drainage) and the equisetums don't come up so much near the roses, but they're all through my backyard and so on. It would be nice to do something productive with the little &%^$#@'s. :) Wonder if it helps with blackspot.