How can I control Bermudagrass organically in my apple orchard?
Answer: Bermudagrass is one of the hardest grasses to control organically. The best thing I’ve read about organic control of Bermudagrass is based around an intense, one-year, series of smother crops strategy worked out by George Kuepper at the Kerr Center for Sustainable Agriculture in Poteau, Oklahoma. For the details, visit http://kerrcenter.com/publication/converted-bermuda-pasture-organic-vegetables/.Unfortunately, this effective strategy would only work for annual vegetable crops or as a pre-plant technique for your apple orchard. Even if your trees are already planted, I recommend that you peruse this publication because it explains a lot about Bermuda’s strengths and weaknesses.I’m a Certified Naturally Grown (same rules as organic) orchardist myself, working at a similar scale as you. My basic Bermudagrass strategy after planting is to establish a thick wood chip mulch (which, by itself, does very little to control Bermuda except to make it easier to pull–if you have the time and energy) and keep knocking it back with an organically approved herbicide in conjunction with pulling up the rhizomes. I’ve tried flame weeding, vinegar-based herbicides, citric acid-based products, and a soap-based product. Of those, flame weeding was probably the cheapest, but not very effective and carrying around the gas tank was cumbersome. The vinegar herbicide was very ineffective. The citric acid herbicide was slightly better than the vinegar but was very expensive.I’ve settled on Scythe?, which is OMRI approved and is essentially pelargonic acid from soaps. It’s not cheap, but it’s cheaper than the vinegar and citric acid herbicides and it does knock back the Bermuda temporarily. The Bermuda will always come roaring back, but persistent sprayings and pulling out rhizomes when you have the time and labor will help you get through the time when the trees are young and especially susceptible to competition from the Bermuda. As the trees get older, the shade inhibits the Bermuda grass slightly and the trees are better able to deal with the competition.Remember, since there is no such thing as an organic systemic herbicide (like Roundup), all these herbicides, including flame weeding, are “contact” herbicides and will only affect the leaf surfaces that they touch (or almost touch, in the case of flame weeding). Consequently, the strategy is to force the roots to keep sending up new growth and eventually exhaust the reserves in the roots. So keep the Bermuda short with mowing or weed-eating and then apply the herbicides. This mowing first will save you money because if you let the Bermuda get too thick, the blades on top will shield those below from the herbicide. I actually use an old-fashioned scythe to accomplish the mowing. If you keep it sharp, it’s an amazingly efficient tool. But a weed-eater will accomplish the same thing. Then I come behind where I’ve mown and spray what’s left with the Scythe? herbicide. When I plant new orchards on a site with Bermuda present, I try to follow the series of smother crops strategy referred to above from the Kerr Center and then establish common fescue as the orchard floor cover. Fescue is easier to control organically, as it can out-compete BermudaFor more information, consult the ATTRA publication Tree Fruits: Organic Production Overview (https://attra.ncat.org/attra-pub/summaries/summary.php?pub=2). This guide is an overview of issues relevant to commercial organic production of temperate zone tree fruits and, to a lesser extent, tree nuts. It includes discussions of marketing and economics, orchard design, and cultural considerations, including crop varieties, site selection, site preparation, soil fertility, weed control, and pest management (insects, diseases, and vertebrates). It raises questions for the grower to consider in making decisions about orchard and enterprise design. Lists of electronic and print resources offer further, more detailed information.