Forbs, grasses
Low
High (>$5000/gross)
Low/no risk
Low
Low–moderate risk
(erosion, wildlife)
Overview
In competitive planting, native plants or otherwise desirable plant species are planted to prevent the spread of weeds or to directly compete against weeds and reduce their population. The effectiveness of this technique relies on the match, or sometimes the mismatch, in resource use (usually light or water) between the weed and desirable competitive plants. It also depends on the ability to initially reduce competition from weeds enough for the outplanted species to get established.
Success of this technique depends upon correctly choosing plant types that will compete with specific weeds of concern. For example, planted grasses will not readily replace shrubs without other tools being used to keep shrubs at bay, but shrubs may replace grasses. Perennial plantings are likely to be more effective than annuals. If the target weed is a shrub, tree or vine that can overtop other planted species and if plantings are not dense enough to inhibit their regrowth, competitive planting will likely fail. Under these conditions, competitive plants can only inhibit regeneration of seedlings and not growth of established plants.
Habitat restoration utilizes the same principles and focuses specifically on restoring ecological functions that have been lost through invasion or disturbance. Native species are planted in target sites or seeds are sown to increase the abundance of native plants and simultaneously to reduce weed populations. Competitive plantings can be most effective when there are at most a few weed species present on the site. It becomes more difficult as the number of weed species and the diversity of traits of those weed species increases. In some cases, non-native species are used in competitive planting projects to initially suppress weed cover while native species are established in a second competitive planting or restoration effort.
Competitive planting is generally more successful when being used to augment an already existing native plant population. In this version of the technique, native plants are added to areas where numerous native plants exist at the site, but native plant cover is below levels found in desirable habitat, possibly due to stressors on the plant population (such as livestock grazing, a fire, long-term drought, etc.).
Competitive plantings are less successful when the weeds being targeted have functional traits that are superior to the native plants they replace, such as greater seed mass, germination rates, plant height, root length, or growth rates. However, some invasive plant species can be reduced with competition from a native plant that has similar competitiveness. Invasive non-native species in California are often better competitors than the natives they replace during at least one portion of their life cycle. In this case, competitive plantings may slow down an invasive plant, but will not provide effective control of the invasive over the long term when used alone.
Competitive planting is most effective when used as one component of an integrated vegetation management program. In many cases, this technique will not work without incorporating pre- and post-planting weed reduction techniques. Regular supplemental weed treatments may be necessary even after the competitive plantings have become mature. Efficacy ratings provided for this technique are based on combining planting with prior weed control treatments to reduce both weed cover and its seed bank. Post-planting weed control will further improve establishment success of competitive plantings. Managers should also prepare to follow up with planting additional competitive plants on a site in subsequent years. This will increase cover to fill in areas where competitive plants may have died or have poor vigor. Although this technique is ineffective at fully eradicating specific weed species, it can substantially increase a site’s habitat quality for wildlife and aesthetic and recreational value for people and reduce total cover of weeds.
How to Use
Competitive planting requires a careful understanding of the ecology of the target site. Weed cover should typically be reduced in advance of competive planting. (Methods should be carefully chosen not to impact competitive plantings. For example, pre-treatment disking or prescribed fire at a site may reduce weeds but may also prevent some native plants from establishing because of soil disturbance that favors weeds.) Once weed populations have been reduced below a target abundance or cover level, native plants can be introduced to the site, such that weeds will be impeded by the natives. Use the first year or few years after weed populations have been reduced to promote the establishment of competitive native plants.
There are two general ways of actively establishing native species on a site: seeding or planting (e.g., transplanting seedlings). Seeds of competitive plants can be directly broadcast into a target area. Seeding rates and species palettes will depend on the characteristics of the site, the surrounding habitat, and the weeds present. Assume that some weed species not currently present on a site will appear and that they will also need to be managed. Post-establishment weeding likely will be needed to prevent, or slow, this secondary invasion. Seeds of competitive species typically need to be incorporated into the soil either by hand tools (such as rakes or hoes) or with a seed drill or other mechanical equipment. Seeding into sites with an extensive weed seed bank often leads to failure because weed seeds will germinate and outcompete natives. Therefore, sites without a weed seed bank should be selected or intensive weed control must be conducted (often for multiple years) prior to seeding to reduce the seed bank.
Transplanting seedlings will overcome issues of seedling competition. This can be done by planting potted plants (typically plants ranging from 2 ½” starts to 1-gallon pots) into a pre-treated area. (To avoid the spread of soil borne pathogens, including Phytophthora, it is essential that potted plants be grown using nursery industry best management practices.) In riparian or marshy areas, plant fragments can be directly transplanted into wet soils from donor sites. Some large shrubs and trees can be ‘pole’ planted into wet soil (e.g., mulefat or willow) as long as the species is capable of resprouting. In pole plantings, the bottom of a branch or pole is deeply buried (e.g., 3’) where it will root into moist soil and develop into a new shrub or tree with minimal care. When transplanting competitive plants, the same techniques that are used in traditional restoration can be employed. These include: irrigating plants, creating berms and basins, using deeper pots in dry soils, and weeding around transplants. In some cases, shrub or tree shelters will need to be added to reduce browsing by wildlife.
Competitive plants can be transplanted into parts of a site in rows or ‘islands’, allowing their seeds to repopulate the remainder of the site in future years. As the first transplants become established, weeds are treated between the rows or around the edge of the islands. Often after several years the competitive plants may produce enough seeds and new seedlings will establish adjacent to the areas where the first transplants were planted. Maintenance is also easier because it allows for easy access to control weeds along planting edges. This technique has been used to re-establish shrublands. Colonization of established habitat rows or islands by rodents seems to help with the success of this method, because they forage on weed seeds along planting edges. This method is a modification of the Bradley method of habitat restoration (see Fuller and Barbe 1985). The Bradley method capitalizes on the competitive abilities of resident desirable plants by starting weeding work from the edges of patches of native plant populations and slowly working into more invaded areas over a period of months or years. The Bradley method can be used to break up large projects into small patches of work thereby reducing initial costs, if budgets are constrained.
Over the long term, populations of competitive plantings may decline against weed species encroachment partly due to environmental or small-scale site differences. For example, the cover of competitive plants will likely decline after a multiple-year drought. When average or above average precipitation occurs after a drought, weed species may fill in the gaps between competitive plants. In contrast however, very few native species are lost from an area due solely to invasive plants. There is often a microhabitat where a few natives can thrive while being surrounded by weeds.
Competitive plantings often establish successfully if the planting sites are hand weeded. If plantings are seeded, weeding will need to be around seedlings and span at least the first and possibly the second and even third growing season. After that, as shrubs grow, small mammals can find shelter under the small shrubs to graze on the weeds, which usually happens in intact shrublands. Land managers can often find small mammals grazing on weeds near an existing shrubland edge too, or close to it. Small mammals are less likely to be found far from an existing natural shelter. Competitive plantings near urban and suburban areas may suffer from an overabundance of herbivores. In those situations, herbivore fencing or cages will need to be installed until plants are well established. If small mammal populations plummet, such as during medium- to long-term droughts, then these herbivory patterns can fall apart and weed densities around young shrubs can be unacceptably high.
The species being used as competitive plants matters, as do the species of weeds that are being targeted. Some native perennial grasses and forbs are competitive once established, while many introduced invasives are more competitive in the germination and seedling stages. Other weeds however, can tolerate high levels of competition. In addition, non-native transformer species (those invasive plants that can transform the structure and function of an ecosystem, such as invasive grasses converting a shrubland, or invasive trees converting a shrubland into forest) are so competitive that their expansion cannot be stopped without intensive long-term management.
The success of competitive plantings is often related to reducing future weed invasions. Other weed control techniques need to be used to get those plantings to the point where they can compete. Focusing only on planting is often not sustainable without combining weed control techniques. Long-term maintenance of desired plant communities may also be key to persistence, if there continues to be import of invasive weeds that may colonize and become abundant on the site. In some habitats, introducing a disturbance regime (such as fire, livestock grazing, flooding, etc.) may help maintain the desired native plant community, if natural disturbances are absent or minimal.
Competitive planting projects are often costly unless labor or plant material are subsidized, such as through volunteer labor. In some special situations a land manager may be able to collect local seeds and spread them on a site that has lower than desired plant cover and achieve some success with competitive plants. However, most competitive planting projects require significant investments in pre-planting weed work and propagation of nursery plants. On the highest cost end of the scale, a project can include collecting local seeds, germinating and propagating a suite of locally collected species in a nursery, working with nurseries that have strict pathogen prevention measures, transplanting potted plants in the field where weeds have been reduced prior to planting by other effective weed control methods, placing the potted plants in protective structures, continuing long-term weeding as needed, and irrigating the competitive plants to increase survival rates or mitigate for below-average rainfall. On this end of the scale, costs can easily exceed $5,000 per acre. In some cases, such as when using a modified Bradley method, the major costs for competitive planting sites will be in labor used for weeding which may only equal hundreds to a few thousand dollars an acre, especially if native plants are adjacent to the site. For some competitive planting projects costs will markedly decline four or more years after the project has started as native competitive plants become established.
If natives are light loving, then planting, especially by seed, several different types of native plants could be competitive. Maintaining gaps between the canopies of native plants is important to help further competitive plants to establish. Conversely, for species that are known to emerge through nonnative (e.g., grass) canopies, sowing without weeding might work, though this has not been successful for several pairings, such as coyote brush seeding in non-native annual grasses.
Historic land uses may also play a role in establishing competitive plants on a site. The disjunct between the species assemblages left by indigenous land management and modern approaches may create problems when managing plant assemblages for desirable species. Land management practices have changed drastically over the past few hundred years in California. As land management practices have transitioned from Native American to Spanish ranchers to today, significant changes in species assemblages and disturbance regimes are present. For example, in some locations fire suppression has created high density, relatively even aged forest stands which then affects other species on the site, including the ability to establish natives. Lack of regular fires in grasslands can alter seedling establishment in grasslands.
Effectiveness of competitive plantings will depend on the ability of competitive plants to suppress target species, by procuring more resources than the target species or by growing taller and shading the target species. If the weeds can tolerate the competitive plants, then the technique will have poor effectiveness. There are a few native species which might prevail in competitive plantings against very difficult weeds, however research on this is limited and some successes might not be replicated elsewhere.
Species that have high rates of spread can disperse to areas where competitive plants are less likely to grow in a dense stand reducing their ability to control those weeds. Considering only a finite area, such as a riparian zone, a high rate of spread would still give the weed some advantage, but in the long run, certain slow perennial competitors, such as valley sedge (Carex barbarae), may prevail. In addition, many invasives are fast-spreading pioneers some of which decline over time against moderate to high competition. Some non-natives initially are abundant after disturbance but can be displaced over time by natives.
Generally speaking, if a weed species has a long-lived seed, over the course of several years some of those seeds will disperse to areas where competitive plants are not as dense or tall and those weed seeds may germinate and establish. All other things being equal, short seed life would be easier to control, but such plants often, if not usually, are adapted to spread quickly and widely.
Control of weeds will depend on the ability of the seeded competitive plants to outcompete the weeds. If the competitive plants can germinate before the weeds and access resources first, they will often be able to reduce weed growth. Since most rainfall in California occurs in the winter and spring this technique would be most effective using competitive plants that germinate during those seasons. Native summer annuals (such as tarweeds) may also germinate in the winter and spring, so they may not compete well with non-natives germinating in the same seasons even though they flower at very different times of the year. If the weed species can produce a large number of seeds or propagules, then it becomes more likely that a few plants will establish in a microhabitat that is favorable to the weed and not as favorable to the competitive plants, thus the competitive plants might not be effective at suppressing the weeds.
For upland shrub restoration, when crews work off a calendar and maintain regular visits to work sites (and given adequate rainfall), through a combination of competition and herbivory, weeds can be kept under control. If small mammal populations plummet, as happens after extended drought, the mechanisms break down.
Control of resprouting weed species by competitive plants will be less effective or take longer and risks of the method failing will be higher. If the weed species has the ability to resprout, then the competitive plants must be able to maintain a competitive ability (such as by having a dense canopy) the entire growing season or even the entire year. For species with a limited ability to resprout, it’s often easy enough for land managers to treat resprouts during site visits. Other slow resprouters are also easy to treat when they appear repeatedly in buffers between seeded areas.
Control of weeds will depend on species-specific factors and not so much on flowering season. The control of weed species will more depend on the canopy and growth of the competitive plants and the type of competitive plant. If the weeds and the competitive plants are the same plant type, (i.e. both grasses) then flowering season can influence control effectiveness. If the weeds flower over multiple seasons then control techniques may take longer. With regular visits, crews can cut back annual species at bud or before flowering and perennials before flowering.
At small scale, competitive planting is a successful technique; as the size of the patch grows the ability of competitive plants to dominate decreases and the ability of weeds to thrive in specific microhabitats increases. In addition, at small scales workers can easily find new weeds and remove them. There are not many cases where wildlands have been planted with competitive plants at very large scales with long-term successes, notable exceptions include aerial hydroseeding (often after wildfires), and large, flat riparian or mesic areas where agricultural equipment can work the site to reduce weeds during the dry season and seed natives efficiently. Plantings could be effective at reducing weed populations at these large scales, but challenges with implementation and costs generally prevent projects at large scales, especially on sites with varying terrain.
As slope increases it becomes difficult for workers to manage weed populations or to prepare for planting or seeding competitive plants on steep slopes. Shrublands tend to be found on steep to very steep slopes and so to work with this limitation crews can plant in strips, to reduce erosion and allow seeds to disperse down the slope. Tamping seeds may help prevent seed losses to runoff. However, weeding the first year during establishment can be difficult, especially for workers on the uphill side of strips. Slow spreading perennials or vines might be a good choice for steep slopes as they can spread up or down the slope to reduce weeds.
As access to a site is decreased due to the distance from a road, it becomes difficult to ensure successful competitive plantings in weed-dominated areas receive the amounts of work necessary to reduce the weeds. If weed populations are low, then weeding techniques far from roads are easier to implement. Some techniques can be effectively used far from roads, such as aerial hydroseeding. There may be exceptions to sites far from roads, but since both plants and associate weed cover need to be managed in the growing season, logistics and effectiveness are all that much more challenged. Conversely, working on a site directly adjacent to a road, even a dirt road, may also be difficult as roads can concentrate rainfall and lead to more weed pressure and flash flood environments that would not occur a short distance from a road edge.
Soil texture can be a significant issue when growing competitive plants on a site. Each soil texture (sand, silt, clay, loam, clay loam, etc.) has unique challenges for establishing plants and the weeds that the soils will support. In rocky areas it becomes difficult to establish cover that would outcompete weeds and the cervices can provide places for weeds to get into and establish. Rocky soils can also be problematic as a safety issue for crews on foot. Clay soils can be difficult to work on as crews can transport new weed seeds into the soil on their boots, and the competitive plants that are selected will need to be tolerant of moist soils for potentially months during a wet year.
Grasslands can be a difficult habitat type in which to use competitive planting. Grasslands lack a tall canopy that creates shade and thatch buildup of native grasses can inhibit germination. Native bunch grasses often do not form dense, closed canopy stands, leaving space for weeds to come in, in between. Thatch build up can result in die-off of native grasses, eliminating thatch build up will assist with establishing other natives in between bunchgrasses. In addition, many wildflower species in grasslands can grow between bunchgrasses, including geophytes, and it may prove difficult to reduce weeds and allow for competitive plants to flourish in this habitat type. In some cases, it is difficult to distinguish invasive grass seedlings from native grass seedlings and if workers cannot detect weeds until late in the season the native seedlings may be reduced or have died due to competition from weeds. The use of native grass plugs can help eliminate some of these difficulties when managing grasslands. The use of biodegradable weed barriers around plugs can help with establishment success, by reducing weed pressure.
Rocky or cobbly soils are extremely difficult to work on especially when trying to dig planting holes for native transplants. It is also difficult for large equipment to drive across rocky soils, and heavy tools may be needed to assist with digging planting tools. There is also less available soil surface for plants to establish from seed as the rocks may take up a portion of the soil surface. It also becomes difficult to remove weeds between rocks.
It becomes increasingly easier to increase competitive plants in areas that are dominated by native plants than in areas dominated by weeds. However, planting into a site that already has high native cover in order to eliminate a species of weed may be very time-consuming. It can be more efficient to just to do the weed control. At high cover levels, collateral damage can become a problem with weed control work, especially around native annuals or small perennials.
Special Tips
A variety of restoration techniques can be used to establish desirable plant species. Choose a site with existing native vegetation. Focus plantings along edges of native habitat to capitalize on adjacent seed rain and herbivory that could keep weeds down (though herbivores may also browse transplants). Tree tubes are highly recommended for oak seedlings, both to improve growth and protect them from deer browsing. When using tree tubes, a porous barrier must be placed over the top to avoid birds getting trapped. Shrub shelters are also helpful for establishing shrubs. Consider temporarily fencing sites that show extensive browsing by wildlife. Consider planting densely to exclude weeds early on and thinning out plantings later as they mature. When transplanting, make sure not to introduce only a single sex of a dioecious species (e.g., willows and mulefat).
Examples of some highly competitive native species are shown below. Verify that a particular species occurs in your region and use local genotypes when available. This list is not complete.
|
Scientific name |
Common name |
Growth form |
Notes |
|
Amsinckia spp. |
Fiddleneck |
Winter annual |
Choose common local species. |
|
Baccharis pilularis |
Coyotebush |
Shrub |
Most upland habitats |
|
Baccharis salicifolia |
Mulefat |
Shrub |
Common in southern and central CA. Riparian habitats. |
|
Croton setiger |
Doveweed |
Summer annual |
Common in southern Ca. Competes with summer weeds |
|
Deinandra fasciculata |
Fascicled-leafed tarweed |
Summer annual |
Common in southern California |
|
Distichlis spicata |
Seashore saltgrass |
Rhizomatous grass |
Saline/alkaline soil |
|
Elymus triticoides |
Creeping wild rye |
Rhizomatous grass |
Oak woodland and grassland |
|
Elymus elymoides |
Squirrel tail grass |
Perennial bunchgrass |
Mountains and Great Basin and Mojave Deserts |
|
Grindelia camporum |
Gumweed |
Perennial forb |
Can persist in degraded grassland |
|
Quercus spp. such as Q. agrifolia, Q. douglasii and Q. lobata |
Coast live oak, blue oak, and valley oak |
Trees |
Creates canopy over time which shades out competition. Grow slowly. |
Creeping wild rye (Elymus triticoides) may be a good species to highlight for planting in some locations especially where there is some summer soil moisture. Alkali heath (Frankenia salina) may be able to compete against perennial pepperweed (Lepidium latifolium) in some wetter areas. Some native annual grasses, such as small fescue (Festuca microstachys) and some native bromes (Bromus spp.) can be somewhat competitive against invasive annual grasses.
Optimal Conditions for Use
Competitive planting is best used in areas where the habitat of the competitive plants matches the site. Competitive plantings can be effective in mesic (moderate moisture) soils where perennial native rhizomatous or stolon-forming species can suppress weed populations. For sites that are flat and wet most of the spring, wetland perennials would be a good fit (and upland species would be a poor fit).
In many parts of California, the weeds invading a given habitat type are a different growth form than the native plants they threaten, and this affects which areas will be most conducive to effective competitive planting. For instance, nonnative annual grasses invading areas with native perennial shrubs are most appropriate for areas that are not too dry or too wet, where shrubs are most likely to establish.
In many arid areas of the state the weed species are annual or occasionally biennials, whereas the natives are annuals and perennials. These weeds tend to have traits that outcompete native annuals and the seedlings of perennial plants, so native seedlings will need assistance (such as irrigation, weeding or an herbivory shelter) to ensure establishment.
Caveats
The competitiveness of most native plant species relative to invasive plants is either unknown or only known through anecdotal observations. There are few, if any, native species that are known to be highly competitive across their range, in all growth stages, in a variety of plant associations and against a variety of weeds commonly encountered in the environment. Each species will perform differently from site to site.
The principles on which competitive planting as a weed reduction technique is founded are sound, but the technique relies on local environmental factors and specific species interactions that may not have been well studied. Practitioners may have difficulty determining which native plants will provide enough competition to suppress local weed populations.
Potential Hazards to Humans, Environment, and Cultural Resources
Human safety. Low risk. Follow general safety precautions for fieldwork.
Cultural resources. Low risk for seeding; moderate risk if significant digging is involved for planting. Surface and subsurface cultural resources should be avoided. Where applicable, obtain pre-disturbance cultural resource surveys and permits.
Habitat. Low-moderate risk. When successful, competitive plantings will build habitat and be a low risk. However, transplanted plants have the risk of carrying Phytophthora or other soil or plant-borne pathogens with them, especially if they are transplanted as potted plants into moist environments. Other pests, such as polyphagous shot-hole borer, can inadvertently be introduced with pole plantings of riparian shrubs and trees. Invasive ants such as the Argentine and red imported fire ant can be introduced through soil. Ensure that plant material is healthy and free of pests before planting. Use of inappropriate plant material can exacerbate invasive plant issues at a site and impact site resilience and habitat quality. Follow guidelines on seed and plant material transfer zones and use local plant material. Seek expert advice when developing plant palettes. Make sure plant material is weed-free and has been correctly identified.
Sensitive species. Low risk. When done correctly, competitive plantings can build habitat for sensitive species. Take care not to plant species that cannot be utilized for a sensitive species occurring on site. As with other techniques, care needs to be taken that activities associated with planting do not harm sensitive species.
Erosion. Low-moderate risk. Using competitive planting techniques may reduce erosion risk over the long-term when weeds are less able to hold the soil than competitive plants, but erosion may increase erosion risk in the short term by exposing the soil surface. This can be mitigated with mulch or other temporary soil cover.
Consider Combining with the Following Non-Chemical Methods
Competitive planting techniques often must be combined with weed reduction methods before and after competitive plants have been introduced to the site. Examples of non-chemical weed reduction techniques that complement planting include hand pulling, hoeing, grazing, prescribed burning, solarization, and mulching.
Don’t Use This Technique When/For
Perennials with a strong ability to resprout will be difficult to control with this technique. Weedy vines (such as morning glories,Convolvulus spp.) that can overtop natives will be difficult to control.
There are several species against which few, if any, competitive natives might prevail, these species will spread underground and eventually occupy the soil (Lepidium latifolium, Calystegia sepium, Pennisetum clandestinum). Oats (Avena spp.) are also a highly successful invader in more mesic to somewhat xeric habitats. Other invasive annual grasses (some Bromus spp.) produce an abundance of seed, are early sprouting and maturing, and thus capture resources more effectively than native annuals.
Supplementary Information
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References
DiTomaso J.M. et al. 2013. Weed Control in Natural Areas in the Western United States. UC Weed Research and Information Center: Davis, CA. 544 pp.
Dreesen, D.R. and G.A. Fenchel. 2008. Deep-planting methods that require minimal or no irrigation to establish riparian trees and shrubs in the Southwest. Journal of Soil and Water Conservation 63:129-133.
Fuller, T.C. and D.G. Barbe. 1985. The Bradley method of eliminating exotic plants from natural reserves. Fremontia 13: 24-25.
Gibson, A., C.R. Nelson, D.Z.Atwater. 2018.Response of bluebunch wheatgrass to invasion: Differences in competitive ability among invader-experienced and invader-naïve populations.Functional Ecology32:1857-1866.
Perry, L., S. Galatowitsch, and C. Rosen. 2004. Competitive control of invasive vegetation: A native wetland sedge suppresses Phalaris arundinacea in carbon-enriched soil. Journal of Applied Ecology 41: 151-162.
Simmons M.T. 2005. Bullying the bullies: The selective control of an exotic, invasive, annual (Rapistrum rugosum) by over-sowing with a competitive native species (Gaillardia pulchella). Restoration Ecology 13:609-615.
Authors and Credit
Lead Author: Christopher McDonald, University of California Extension Weed Specialist, UC ANR
Co-authors:
Jessica Bailey, Landscape
Architect, California Native Grassland Association
Pamela Beitz, Integrated Pest
Management Specialist, East Bay Regional Parks District
Jutta Burger, Science Program
Director, California Invasive Plant Council
Sandy DeSimone, Science Director,
Audubon Starr Ranch
Susan Schwartz, President, Friends
of Five Creeks
David Thomson, Senior Ecologist, San Francisco Bay Bird
Observatory
Additional Contributors:
Jeanne Hammond, Senior Biologist and Restoration Program Manager,
Olofson Environmental, Inc.
Tom Reyes, Integrated Pest
Management Coordinator, Midpeninsula Regional Open
Space District
Efficacies
| Rating | |||
|---|---|---|---|
| Plant | Flowering Period | ||
| Winter | Fair | ||
| Spring | Fair | ||
| Summer | Fair | ||
| Fall | Fair | ||
| Multiple Seasons | Fair | ||
| None | Fair | ||
| Plant | Germination | ||
| Winter | Good | ||
| Winter / Spring | Fair | ||
| Spring / Summer | Fair | ||
| Opportunistic | Poor | ||
| Plant | Palatability | ||
| Yes | No Information | ||
| No | No Information | ||
| Partial | No Information | ||
| Plant | Plant Growth Form | ||
| Grass | Fair | ||
| Forb | Fair | ||
| Shrub | Poor | ||
| Tree | Poor | ||
| Vine | Poor | ||
| Plant | Plant Type | ||
| Annual | Fair | ||
| Biennial | Fair | ||
| Perennial | Poor | ||
| Plant | Propagule Production | ||
| Low (<1000/square meter) | Fair | ||
| Moderate (1000–10,000/square meter) | Poor | ||
| High (>10,000/square meter) | Poor | ||
| Plant | Rate of Spread | ||
| High (doubling in <10 year) | Poor | ||
| Moderate (50–75% increase in 10 years) | Poor | ||
| Slow Rate (25% increase in 10 years) | Fair | ||
| Plant | Resprouting / Regenerative Capacity | ||
| Low | Fair | ||
| Moderate | Poor | ||
| High | Poor | ||
| None | Fair | ||
| Plant | Seed Life | ||
| Short (≤3 years) | Good | ||
| Moderate (4–10 years) | Fair | ||
| Long (>10 years) | Poor | ||
| Plant | Type of Reproduction | ||
| Seed | Fair | ||
| Vegetative | Poor | ||
| Seed & Vegetative | Poor | ||
| Plant | Type of Vegetative Reproduction | ||
| Rhizome / Stolon / Stem | Poor | ||
| Bulb / Corm / Tuber | Poor | ||
| Root sprout / Sucker / Crown sprout | Poor | ||
| Site | Existing Desirable Plant Cover | ||
| <10% | Poor | ||
| 10–25% | Fair | ||
| 26–50% | Good | ||
| 51–75% | Good | ||
| >75% | Good | ||
| Site | Ground Condition | ||
| Muddy | Fair | ||
| Smooth | Fair | ||
| Cobbly | Poor | ||
| Rocky | Poor | ||
| Site | Habitat | ||
| Marsh / Wetland | Fair | ||
| Riparian | Fair | ||
| Grassland | Fair | ||
| Shrubland | Fair | ||
| Woodland / Forest | Fair | ||
| Site | Level of Tolerable Disturbance | ||
| Low | Fair | ||
| Medium | Good | ||
| High | Good | ||
| Site | Slope | ||
| Flat | Good | ||
| Moderate (10–40%) | Fair | ||
| Steep (>40%) | Poor | ||
| Site | Target Area | ||
| <40 square feet | Good | ||
| 0.001–0.01 acre | Good | ||
| 0.02–0.1 acre | Good | ||
| 0.2–1 acre | Good | ||
| 2–10 acres | Fair | ||
| 11–50 acres | Fair | ||
| 51–100 acres | Fair | ||
| >100 acres | Fair | ||
| Site | Targeted Invasive Plant Cover | ||
| <1% | Good | ||
| 1–10% | Good | ||
| 11–25% | Fair | ||
| 26–50% | Poor | ||
| 51–75% | Poor | ||
| >75% | Poor | ||
| Site | Vehicle Accessibility | ||
| Roadside | Good | ||
| <100 feet from road | Good | ||
| 100–1000 feet from road | Fair | ||
| >1000 feet from road | Fair | ||
