Restoration/Revegetation Plan Guidelines

Choosing Revegetation Methods
You must first decide upon the most appropriate revegetation method for your site(s). There are
two approaches that can be used to restore the area to a more stable, desirable state: passive
revegetation and active revegetation. You may use active in one place (e.g. high on banks) and
passive in another (e.g. lower on the same banks).
Passive revegetation means replanting by natural processes. Nature itself becomes the restoration
agent! This method requires the least effort and expertise to restore native riparian vegetation.
Wind, rain, and high stream flows generally will carry seeds, plants, and sediment downstream,
where they will settle on the lower stream banks naturally. This process is periodic and may take
several years. Passive revegetation is unintrusive and fewer disturbances may result in less erosion.
It also ensures the introduction of local genetic stock, including both native and exotic plants. If
exotic pest plants dominate adjacent areas, the eradication site is at risk of being repopulated by
these invasive non-native plants.
Passive revegetation is most appropriate when:
• There are established native plants that provide seeds and propagules, either on-site or
upstream.
• Few non-native plants inhabit the site or exist upstream of the site
• The site does not contain a lot of disturbed, unvegetated sunny ground that could act as a
magnet for non-native pest plants.
• The soils are stable and at low risk of erosion.
• The site tends to flood each year, allowing nearby native plant material to settle and become
established.
If these conditions exist, then attempting active revegetation may be a waste of time and resources.
Active revegetation means planting by hand. It usually involves installing and maintaining an
irrigation system, and following a weed management schedule. It is often needed to revegetate the
higher, drier areas adjacent to streams that may not be affected by frequent flooding. It is generally
recommended that you postpone active revegetation until you have the most invasive pest plants
under control, since it may be difficult to avoid harming desirable plants during follow-up
herbicide treatments. Adequate control can take more than one season.
Active revegetation is most appropriate when:
• The site is located downstream from or near invasive plant species that rapidly invade sites
(such as broom, thistle, mustard, and hemlock). In such cases, prompt revegetation with natives
may be necessary to prevent invasion of your site.
• The soil or stream bank is unstable and at high risk of erosion.
Rev. 05/25/04
• A landowner strongly desires a privacy screen or is worried about bank erosion following pest
plant removal.
When an eradication site is on an unstable bank or a vulnerable site, revegetation alone may not
provide adequate soil or bank stabilization. Soil retention materials and stabilizing structures
may be needed to adequately prevent erosion and bank failure. In such cases, materials such as
erosion control fabrics and engineered structures should be considered before engaging in
invasive plant removal. Your Restoration/Revegetation Plan should include both proposed bank
stabilization and revegetation proposals, if needed. For structural changes, consult with a
professional. Some sources to consider consulting with are private engineering firms,
government agencies, Resource Conservation Districts, and landscape architects.
Restoration of native plant communities is an art and science unto itself. In planning active
revegetation, it is best to err on the side of caution and remember that work on your site will likely
have impacts downstream. Choose the simplest project that will still satisfy your goals. We
strongly encourage the use of locally grown native stock. Seek advice from experienced
professionals before you act, keeping in mind that people knowledgeable about native plants or
stream dynamics are not necessarily experts in revegetation, or visa versa. As a general rule, plant
most species in the fall and early winter to take advantage of winter rains and ensure survival.
Plants will need irrigation for the first one or two years.