Nonchemical Strategies FOR MANAGING INVASIVE SPECIES IN YOUR BACKYARD / By Jessica Toro
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any of us understand the ecological concern of the impact of invasives on our natural world. But it’s also important to be aware of how invasives directly impact you. Barberry is increasing tick abundance and the number of infected ticks found both in the natural landscape and in our lawns. Giant hogweed can cause second-degree burns to exposed skin. Invasive plants degrade garden beds and vegetable gardens, and impact farming on all scales. We need to broaden our perspective that invasives are damaging just nature, and also include ourselves as being threatened by these species. When considering nonchemical strategies to control invasive species, this subset of approaches includes hand pulling (hand removal), mechanical, propane torching, biocontrol, smothering treatments, grazing, or a combination of these strategies to manage a variety of invasive plants. Paramount to the success of your project is the need to evaluate the entire property for the presence and absence of invasive species, environmental conditions, and the context of the site in the larger landscape. This will help you determine the size of the project and whether you want to tackle control efforts all at once or in phases. Once you have a list of invasives, think about the biology of each species. Are some a greater concern or have a greater urgency for control? It may be best to start with the species that has just entered the property and has spread the least. They will be fewer and smaller, making it easier to control them with nonchemical methods. You will be preventing them from spreading and becoming more problematic. If working in phases, you may want to consider looking where there are no invasives and expanding that area instead of dealing with the heaviest invasion first. It is important to understand the environmental conditions of your property. If it is wet, even nonchemical approaches may need wetland permits. In a garden setting, you may not want to smother all the plants. Think about how your property fits into your neighborhood and larger landscape. If all your neighbors have bittersweet vines, there is a seed source to reinvade your property even after you have gained successful control. You may wish to prioritize species for control that don’t have nearby seed sources. In this vein of thinking, highway departments are one of the most common spreaders of invasive species along roadsides. You may want to work with them so that their mowing equipment does not bring seed and plant material onto your property. In the end, prevention is the cheapest approach for invasive control. The two greatest things you will need are patience and commitment. 14
Spring / Summer 2019 | www.OurBerkshireTimes.com
Nonchemical strategies require longer periods of time and greater repetition to achieve desired goals. Start small and be successful! Manual control includes hand pulling, cutting of seedheads, and digging up smaller shrubs, trees, and vines. The manual approach is great for herbaceous invasives (garlic mustard, dame’s rocket, narrow bittercress) and when shrubs, trees, and vines or knotweed are small. The area you can cover is directly related to the amount of time you have, and the size and abundance of the invasives. For many landowners, an area over a half acre may not be feasible for handpulling. Digging in wetlands or wetland buffer should be discussed with your local conservation commission. Mechanical treatment can be accomplished with brush cutters, chain saws, tractors with brush hogs, or larger equipment such as forestry or flail mowers. This could be a good option if you have larger-sized invasives like honeysuckle or buckthorn trees. Large equipment will even mulch up the vegetation, returning the nutrients to the ground. Mechanical treatment can be timed when the invasive’s root storage is depleted, which requires the plants to put energy into regrowth instead of restocking the root reserves through photosynthesis. Mechanical is also good to do prior to grazing or propane torching. Propane torching is another tool that is selective for invasives and can be used easily in garden, landscape, and farming areas. It works better on certain species than others. The downside to propane torching is that you are using fuel to power the torch and multiple tanks over small areas. How quickly you cover an area is dependent on the size of the torch and the number of plants. For specific species such as purple loosestrife, biocontrols have been very successful. Unfortunately, most biocontrols are still in development. Each approach is a different tool that should be kept as an option. Every situation is different, and each management tool has its limitations. To achieve success, landowners need to match their goals, site, species, and biology to the appropriate management options. ~Jessica Toro is the co-owner of Native Habitat Restoration, based in Stockbridge, Massachusetts. She has designed and implemented many invasive control and restoration efforts over the past 18 years. Prior to starting Native Habitat Restoration, Jessica worked for 11 years at the Nature Conservancy as the conservation program manager of the Berkshire Taconic Landscape. www.nativehabitatrestoration.weebly.com