A worldwide community photographing and learning about wildlife
Eupatorium capillifolium
"Forest" of tall perennial plants growing in a dried pond bottom. Herbaceous individual stalks with feathery foliage. These plants are very common; usually regarded as weeds. As such, they are rarely allowed to grow undisturbed for this long and hardly ever seen this tall... some stalks approaching 3m. They develop white blooms in the fall, and spread by seed as well as by underground roots that spread to form large colonies, as seen here.
Wetland, Pond Margins, Pastures, Meadows, Scrub. Native to the Southeastern United States. These specimens located in the Violet Cury Nature Preserve.
Contains mild toxins that should be avoided by livestock.
I wonder if that could possibly be fennel? I lived in Sacramento for a while, and there was a lot of it growing wild there. This stuff looks very much like that.