spp.) are not only annoying but incredibly invasive, especially in prairies, savannas, and open woodlands. Seed survival in soil can be very long (at least 100 years for certain species!), so when the site is opened up by tree or brush removal, expect to start seeing brambles the next year.
Bramble control should be an integrated part of any burn program, since brambles are very fire sensitive and are top-killed readily. However, although fire top-kills, it does not eliminate the underground network of rhizomes, and new shoots soon arise from underground buds. In fact, often fire may appear to stimulate bramble growth, since not only do you get new shoots at the sites of last-year's canes, but from root suckers arising from the underground network.
We control brambles by spraying all the resprouts that arise from this underground bramble network. We do a thorough canvas of each area, spraying every new shoot with triclopyr (Garlon 3A at 3.5% aqueous; blue dye added). Last year's canes, usually still visible, can be used to help find the new shoots.
It is important to start spraying when the shoots are just up, because the longer you wait, the bigger they get, and the more herbicide they require. In southern Wisconsin, May is generally the best time to spray brambles. However, not all bramble shoots come up at the same time, so to eradicate an area, it must be canvassed at least twice (three times is better).
Note that although this post deals with brambles, we spray anything "bad" we find during our canvases. This includes resprouts of other woody species, especially honeysuckle and buckthorn, and the occasional autumn olive, Japanese barberry, etc. Sumac, another woody species that can be controlled by spraying resprouts, comes in early June.