Redwood Reader

40. Restoration of a native plant system.
From: Manual of California Native Plants
This article has really useful information regarding restoration with native species of plants, why and why nots and dos and don’ts. He points out the mycorhizzial ground between plants, probable duration of restarting fungal activity, weeds and grasses, cattle and how to choose a native plant nurseryman. My main point here is the entire ground is part of the network and is glomalin conditioned to hold water, and that native plantsthrive when allowed because of mycological associations. Another great round of opportunities for research and plant science work, and we concur with the lack of available data on conditions over the last 500 years. Click on the link to Las Pilatas Nursery for an outstanding collection of over 1500 text pages dealing with California Native plants, ecosystems, wildlife,etc.

Restoration of a native plant system (Putting your ecology back on track.)
In our Calif. ecosystems the distant past(greater than 10,000 years) has little or no relevance on the present. We are trying to find historical accounts of the period in the 1700's when the plant communities were last stable. After that, fire frequency changes. The records even in the 1800's are bad at best. Our ecology is changing so fast we are having trouble documenting plant assoc. on a site (never mind mycorrhizal assoc.) from only 20-30 years before. Our site is a case in point. The neighbors that have moved in since the 1985 fire assume the hillsides always looked as they do now. Only the largest crown sprouters remain the same.
We have been trying to revegetate back to the original communities using every trick we can think of. So far we have found:
1. No site is special or mystical. All react appropriately if you include past plant community, (ideally would be to track the last 500 years) mycorrhizal assoc., soil and climate in your plan of attack.
2. You can only successfully revegetate plant species that are members of the original plant community or close to it. The grassland community will best support the grassland species and the chaparral community will best support the chaparral species. Trying to make an area other than what it is will bring in the pioneers from the appropriate community. This is why history is important. As an example, Baccharis moves into the Coastal Sage Scrub areas that have been over the years converted into grasslands. The plant community reverts to the original plant community, as we stated earlier. It may take 200 years but if left alone it generally will. The roots and mycorrhizal assoc. will move about 2-5 foot per year. If a colonizer can become established a herbivore will usually carry a fungal inoculum to it.
We've been told the prairie was easy to restore, 'just burn it off after 3-5 years, the non-natives cannot take the fire'. That was in the mid-west prairie with their protocols. That would be very detrimental to our Calif. ecosystems! Our communities appear to be much longer term because of moisture stress, and possess a dual cycle with perennials, shrubs and trees. Again, each community needs to be examined on its own, each climate is different and each soil type is different. The coastal prairie is different from the valley grassland and much different from the mid-west prairie or the African savanna by climates, soils, and plant species.
3. If the plant community has any vitality left in it you can use it to help you by planting community-supported plants and letting the strengthened community help you suppress the non-native weeds. We have been planting one-watered native landscaping for two years now using this approach. We only water once, forever. You have to follow carefully the plant community, climate and soil of each site for this to work. But it has worked to date in the following communities; Chaparral, Coastal Sage Scrub, Foothill Woodland, Closed Cone Pine Forest, Coastal Prairie, and Yellow Pine forest. We have had failure only in the riparian community.
To determine if the mycorrhizal grid is still intact. Are there any native species left on the site? If so, is there intact(non-cut with rippers and ditches) soil between plants? If so, the areas between plants can be considered mycorrhizal. Has only the top few inches of the soil been disturbed even though the surface plants are removed? If the disturbance was within the last 4 years or so, (a few systems last longer, most are viable for 2-5 years) you can treat it as a mycorrhizal site and restart the system.
The weed suppression is dramatic in many undisturbed communities on many weeds (through allelopathy, gradual buildup of the litter layer, the fact that most of the mycorrhizae that help each plant in the community to survive through increased availability of nutrients and suppression of pathogens are not in association with the weedy, introduced species and all plants and animals in the community from microorganisms up actively attack any non-community specific species up to a certain point. An analogy would be that the suppression of weeds by an undisturbed plant community is like suppression of disease by our body's immune system). You'll find a few survive long term but not many. Next time you go into an area with disturbance next to a pristine area look how the weeds are having trouble extending into the undisturbed area. With a little help from you and I they cannot. This includes grasslands.
3a. You have to suppress the growth of the weeds or remove the weeds at the correct time of year that is appropriate for the community upon which you are working, with minimum disturbance. Any disturbance of the soil or addition of water or fertilizer is detrimental to the native plants but encourages the growth of the weeds(ruderals). Timing varies by community, climate, soil, and sometimes by species. That is one of the reasons we look at sprays on many sites. Soil disturbance of any type, no matter how well intentioned is still an infection point. But you need to know your site's plants before you commit to spray. We know of no other way to remove the non-natives and ruderals without soil disturbance in a short period of time, if we are trying to recover or protect a community in years instead of centuries. Whether it be by tractor disc or human hand it is still soil disturbance and on bad sites this is not acceptable.
4. Knowing that the weeds emerge before the native plants has caused us to try spraying with Round-up to suppress the weeds and encourage the later emerging natives. (Trappe et. al. lists Round-up as no problem for mycorrhiza and our experience has been it kills only what is green with little or no inhibition of later seedlings.) This has proven to be somewhat effective as most (but not all) perennial grasses and dec. shrubs are brown at this time (early Dec.) and not bothered by the sprays. This has to be done very early or very carefully though because the bulbs and native annuals come up in at this same time along with some of the perennial grasses sprouting about then. A very short term pre-emergent may be the answer although many of the ruderals are resistant to pre-emergents and early native sprouters will be hurt. You really need to do a site survey year to year before to see if there are rare plants on site and if the site is evolving native or non-native. Can you make a spray in a non-lethal way to your on-site natives? We've found this early approach to be most effective if used during drought years after the site's energy has been recharged. Do not use it during wet years unless you follow up with a January community-specific wildflower seeding. That is the only way you'll see wildflowers in many of the disturbed communities. Spraying is only an alternative when plant communities have been almost destroyed and need to be helped to recover their balance short-term. The tradeoff, do we lose a few common species to save the long cycle fire-followers?
5. Knowing that another set of the non-natives is usually green and set seed after the wildflowers set seed led us to try spot spraying with Round-up afterwards. You also have to cover each perennial before you spray. This proved to be more effective but the timing has to be exact. The mustard and Starthistle have to be in mid-flower when they have committed their energy to reproduction but before they have set seed. Again, it should be sprayed in drought years if possible.
6a. We tried grazing down the ruderals but the horses selectively ate the native bunch grasses and annual grasses further tweaking the disturbed community in favor of the ruderals. We've seen the same thing happen with cattle on other sites(they ate the perennials and trees also). We also noticed that the weeds that were in the hay but not in the ryegrass were very few indeed. These radiated away from the horse's feeding pen. Although this secondary source was relatively minor it should be watched as a problem in strict sites. (Along horse paths.)
6b. We tried mowing down the weeds to create a litter layer but the weeds can set seed when they are only an inch tall!
7a. From these tries over a 5-year program we offer these theories on communities with seasonal wildflowers.
7b. The displacement of weeds(ruderals) and non-natives is possible in most of our native ecosystems as long as some of the plant community is intact.
7c. No single approach will work. All levels of the community from the microorganisms up must be helped.
7d. If two sprayings, early and late are used, you must use plant community specific pioneer wildflowers to cover the ground and charge the grid during the critical spring 'energy capture'. Covering the ground is important as the weeds have trouble infecting a closed biosystem and covered ground. We are in favor of using species that are widely in use, native throughout most of Calif. and do not need to be site specific. There have been a series of almost criminal substitutions for narrow site specific plants. (Non-native Bromus for the native one. Sometimes a sub-species from S.Cal. gets used in N.CAL. and such, ruining the sub-species.) We would rather see the same species used every time state wide so we at least know where the aliens came from. Our inclination is to divide the poppies into Munz's (1974) 4 sub-forms of Eschscholzia and use the appropriate one in the right area of the state, combined with Lupinus succulentus, Lupinus polycarpus, Lupinus bicolor ssp. marginatus, and Clarkia purpurea ssp. quad..
Most of the pretty, showy wildflowers are either pioneer plants in plant communities where they get buried with vegetation or an important part of the long term ecosystem in grasslands, deserts and prairies. If you are planting wildflowers in communities other than prairie, grassland, meadow, foothill woodland, and most desert sites your wildflowers will be unstable pioneers and disappear after a few years.
Mother nature does this after a fire with fire following pioneer plants covering the ground, feeding the mycorrhizal grid, and then declining and dying, further feeding the grid as the climax seedlings mature in.
7e. We feel grasses cannot be replanted back into many of these sites until you have at least a partial control of weeds as it limits your strategies. Planting the larger summer species would be a better alternative, (for example the right shrub Buckwheat (Eriogonum sp.) for the site.)
7f. It may take 5-70 years of active restoration strategies to achieve a stable, viable, native plant community.
7g. We're realists and realize that although we think they are an ecological disaster, cattle will not go away. Grazers can be used in place of Round-up but only within windows that allow the wildflowers to grow and seed with no stresses and the perennials to set seed during the wet years. In much of Calif. this would mean that cattle are only acceptable from July through Dec., and a second period in May-June during the extreme drought years. During years of normal or higher rainfall, keep cattle numbers down. There are very serious down sides to cattle. They weigh too much. Compacted soil suppresses mycorrhiza and encourages weeds. They tear holes in the light litter that covers many native communities giving entry points for the always aggressive weeds. They carry non-native seeds from their past(previous pasture) and infect everywhere they go. They also favor the worst weeds over the natives by eating the more palatable natives first.
7h. You must work with community, climate and soil-specific ideas. You must work with the strategies of that community to help that community fend off the invading non-native species.
7i. The community can only move out and recapture an area a few feet a year, usually with stops and starts. Start in one area and work out. (See the Bradley Method..Fremontia, Vol.13, No.2)
7j. Our native community works on a beneficial cycle and the introduced weeds disrupt this cycle. This shows up very well in areas that are disturbed next to an intact community. The weeds try to move out into the community but are strongly suppressed as long as the community is intact. If the fungal-plant community fails, the weeds take over. A site covered with weeds in the middle of a plant community is indicative of a struggling community.
7k. If you need to reseed for some reason, each site needs to be treated with some thought. Most intact sites should not be reseeded. We usually use the correct poppy and lupine for the site as the pioneer species to re-hab within a VAM (vesicular-arbuscular mycorrhiza) system. These facultative mycotrophs have proven to be what rye grass was billed to be, benign to the environment but supportive of the community and soil structure.
If the site is mid to low elevation Ectomycorrhizal (pine forests, oak woodland, mixed evergreen) use a combination of lupines, deerweed(Lotus), and native vetch to reseed if needed. No grass. Our preferred plants are lupines as they are facultatively VAM nitrogen fixers and have roots that are among the strongest soil penetrators. Higher elevation forest sites are best left alone because community specific seed is not available.
Finally, the best way to preserve rare plants is to not graze, seed or disturb a site. Check your county, most are still recommending seeding all disturbed sites with ryegrass. Send them a copy of this article, hopefully you will save an ecosystem.
Contract Grown, Site Specific plant material
Many sites, from a single homeowner, to a large pipeline need site specific plant material grown.
Much of what we grow goes to these sites. We are hearing of, and seeing requirements for site specific mycorrhiza, or proof of mycorrhiza on the root structures. This causes me concern. Here is a list of problems.
1. Slides of the mycorrhizal roots are without meaning. If you do not know what species the mycorrhiza is, root slides are valueless. Moreover mycorrhizas can be soft as plants are. A mycorrhiza that is viable in a greenhouse or with high water/fertility is worth little or nothing in the wild. (It can i.d. out to the same species but not be hardy in the wild.)
2. Dictating to the grower how to grow mycorrhizal plants is laughable. We are tracking for each site specific species, (at present) 1200+ different variables/species. With the mainline species we only need to track only 5-10. These are proprietary and range from light intensity to mycorrhizal type.
3. We are hearing of many growers growing natives for the first time getting site specific projects. We are often called afterwards to re-grow the plant material to replant. You cannot grow natives as other plant material has been grown and have viable mycorrhiza.
Here is what I'd like to see required and why.
1. Require the grower to provide proof that he/she has grown at least plants(more than one) from that genera before. (On some weird things you may only find a grower that has grown that family before.)
2. Require the grower to provide a sworn statement that the stock has no fungicides or insecticides applied. Have an analysis done if it is questionable. Mycorrhiza do not tolerate either very well. (Other native growers, e.g., Native Sons, Yerba Buena, Theodore Payne, etc., do not use insecticides or fungicides past the propagation stage.)
3. Use a grower from an equal or harsher climate than the site. (Soft plants and mycorrhiza are unstable in a harsher site. The plants do not need to be site grown.)
"There are no silver bullets."(Trappe) Good ecology, botany, mycology and their use through horticulture are the primary tools we have.
Copyright 1995 Las Pilitas Nursery Santa Margarita - Escondido