A Few Words About Weeds
The simplest definition of a weed is "a plant out of place." If you have a garden, you are probably familiar with weeds, their impact on the productivity of your garden, and how difficult it can be to get rid of them. Weed species in the larger landscape have a similar impact and are equally difficult to remove. Familiar range weeds include russian thistle, cheat grass, tamarisk, russian olive, and knapweed. Some of these plants have beautiful flowers and are often sold as landscaping plants.
In the larger landscape, these weeds are plants that people inadvertently (in the case of russian thistle), or intentionally (in the case of tamarisk or russian olive) brought to the Western United States. Some of these plants "escaped" from human-inhabited areas into the surrounding areas. Cattle, horses, trains, boats, and wagons all served as initial carriers for these "invaders." Today, mountain bikes, camping equipment, and off-road vehicles are spreading these invasive exotic plants faster than ever.
Noxious weeds are those that are particularly tenacious and do not eventually stabilize within the native plant mosaic. Plants such as these have become so commonplace that many of us cannot recall living without them and accept them as "belonging."
The ability of noxious weeds to out-compete native species is hardly a "natural" occurrence, or an example of "nature doing its thing." Most of the noxious weed species have been introduced by people for ornamental plantings, erosion control, food, or by accident. Attempting to tackle this huge problem is an incredibly labor-intensive endeavor and a great deal of planning and research are required to find effective strategies.
A part of that research is evaluating what is possible. For instance, erradicating russian olives and tamarisks along the Colorado River near Moab is probably unlikely to succeed. To remove them and keep them out of Mill Creek Canyon or specific stretches of river, on the other hand, is very feasible. And keeping Russian olive and elm from dominating the Colorado River from Cisco to Moab is very possible as the current infestation level is extremely low. The key is getting to the problem while it is still small and understanding that extensive follow-up will be needed.
Although it may appear impossible to do anything about weeds, the prospect of simply living with them is not benign. In the desert, the side canyons and springs are particularly important areas where it is possible to prevent the progress of weed species.
The Bradley Method (excerpted from Bringing Back the Bush )
The Bradley Method of Bush Regeneration uses the landscape's ability to heal itself to restore native vegetation to a site. The Bradley Method is most applicable when the primary problem is invasive exotic plants or weeds. This may be a part of the overall strategy for a larger revegetation project, or it may be the only strategy used. The Bradley Method is most effective when there are healthy plant communities adjacent to the project site. The Bradley Method is a way of prioritizing your weeding efforts, and can make the most overwhelming project possible. Remember, these weeds didn't move in overnight; it will take at least as long to remove them as it took them to colonize the site.
Bradley Method General Plan of Work
1. Prevent degradation of good areas
In "good" areas, weeds are generally scattered in healthy native plant communities. Remove these weeds. Whenever you visit the site, locate and remove any you missed.
2. Improve the next best areas
Begin additional weeding in areas close to healthy native vegetation. Never clear weeds beyond approximately three yards from healthy native plants.
3. Hold the advantage gained
DO NOT OVERCLEAR. Weeds will generally continue to germinate and thrive if the area has no native plants. Follow-up weeding around all the native plants will be necessary at least twice a year. When a new wave of weeds germinate, take the time to visit the site and weed around each native plant again to help favor its growth.
4. Cautiously move into the really bad areas
Keep working along the edge being regenerated, making new clearings smaller as weeds become thicker. Always look for the odd native plant in a stand of weeds and concentrate your weeding effort around these plants.
5. Cautiously move into the worst areas
Do not clear a block of solid weeds until healthy natives border it. It is tempting and satisfying to clear huge areas – but the weeds will simply return if they have no competition from native plants. Many weeds thrive in disturbed soils – so don't forget to minimize damage to the soil.
Because the Bradley Method basic principles and workplan dictate working from areas of healthy plants to infested areas, initially this method can appear very slow. Resist temptations to clear large areas of weed. Although this has more immediate visual impact, it will make much more work for you later.
Furthermore, never weed a larger area than native growth can recolonize. In the worst areas, lots of follow-up weeding for seedlings is necessary to favor natives. An exception is when you are working in a large area completely infested with weeds. If you are helping this area along by planting, you may want to clear weeds first to make your initial work easier. In follow-up maintenance, however, return to the Bradley Method.
Strategies to Help the Bradley Method Along:
How to re-establish native plants where there is little or no healthy vegetation nearby
At times you may want to restore locations which the Bradley Method might take some fifty years to clean up. A landowner is unlikely to commit to paying for a project over fifty years, and most people want to see results within five years. In general, the Bradley Method actually takes less time than it first appears, but there are strategies to speed up the process.
When areas have been severely damaged by four-wheel-drive vehicles, bicycles, foot traffic or grazing, it is sometimes necessary and acceptable to add seed, move plants in from adjacent areas, plant seedlings grown elsewhere, or plant pole plantings or other vegetative means for propagating plants on the site. On recently disturbed sites, adding plant materials and additional native seeds may help prevent the establishment of large stands of weeds.