Weed Management and Invasive Species Control - Project Planning and Management for Ecological Restoration - page 189

herbicide or fire. This should eliminate or significantly reduce the weed seed bank in the soil.
Reducing the soil seed bank is followed by seeding the site with desirable native species, typically
forbs and grasses, before or shortly after installing woody native plants.
Weed Control Principles
The following weed control principles apply to restoration sites and may also apply to natural areas
and wildlife management areas:
1. Survey your project site frequently to locate and map any new infestations of weeds and
invasive plants. This is assuming that you have identified and evaluated weeds and invasive
plants during your site analysis (chapter 4) and have attempted to control or eradicate
weeds and invasive plants of concern during site preparation (chapter 10).
2. Aim weed control activities to very-high- and high-priority, targeted weed species.
3. Use selective control techniques on the targeted weeds. Avoid using large-scale
nonselective techniques, such as discing, except when preparing a site to be seeded.
4. Control weeds before they have set seed that year. If the weed has already lowered but the
seeds have not yet been dispersed, cut off the seed heads and bag and remove them from
the site, or remove the entire plant from the site.
5. Weed control is best done as soon as feasible after identifying the infestation. This is
particularly important for the highest-priority weeds, which can rapidly expand their range.
6. Control of weeds should be based on the plant's life cycle. Therefore, use methods
appropriate to whether the plant is an annual, a biennial, or a perennial. You should follow
up on the success of any approach regardless of the life cycle of the species.
7. If the weed has not set seed and will not regenerate itself from the root system after
pulling, uprooting, or hoeing, place the weed on the ground where it was removed, to
mulch that spot.
8. Uprooting, pulling, or hoeing weeds is best done when the soil is moist.
9. Limit the use of chemical herbicides to only those perennial plants that reproduce
vegetatively and are not easily controlled with other methods. Chemical herbicides may
pose threats to restoration areas through toxicity to mycorrhizal fungi and soil microflora.
10 . Avoid disturbing native groundcovers while controlling weeds.
11. Encourage native groundcovers, especially those that reproduce vegetatively, by removing
weeds next to existing colonies.
12 . Reseed or replant large bare areas with appropriate native species so that weeds cannot
easily re-invade the site.
13. Keep a minimum of a three-foot-diameter area around installed trees, shrubs, and
groundcovers free of weeds.
14. Use locally collected or locally appropriate native seed mixes for cover crops. Avoid the use
of seed mixes with exotic species. Be aware that there are nonnatives that do not spread, so
consult with local experts for your area. In many cases, the behavior of nonnatives is not
fully understood, and you may inadvertently introduce a problem onto your site.