Shrubs, trees
High
High (>$5000/gross)
Low risk
Low–moderate risk
Low/no risk
Low (wildlife)
Overview
Repeated cutting of plant stems with pruners, loppers, shears or saws is a technique for invasive plant control that can be effective over time, depending on the type of plant being targeted and the frequency of cutting. It removes aboveground biomass and starves roots and other below-ground storage structures if leaves and stems are kept from regrowing. Single cuts to remove seed heads are also standard practice to stop seed production.
Repeated cutting is useful in areas where the density of the target weed is low, where ground disturbance should be minimized, and where a target weed is interspersed with native vegetation that could be damaged by other control techniques. Cutting at short, regular intervals is essential for this technique to be effective at reducing target species cover over the long-term. This technique is not typically used alone to control weed species because it is very labor intensive and requires repeated follow-up.
Pruners, loppers, shears, and saws are considered must-have tools for manual weed work by most practitioners. There are many different types from which to choose. Pruners (often called hand pruners) are used with one hand and can cut woody and rigid herbaceous stems up to ¼-½” thick. Loppers have long handles that require two hands to use. They are typically 1-3 ft. long and are used for thicker, hard-to-reach stems where more leverage is needed. Pruners and loppers are available as anvil or bypass types. Anvil types have one blade that cuts through the stem against a flat surface (the “anvil”). Bypass types have curved blades that overlap when the tool is closed to cut using a shearing motion. Hedge or grass shears have long blades and function like scissors. They are used with two hands and are designed to cut thin, fleshy, and fibrous stems. Shears can be used to control grass reproduction at flowering and before seed set. Pruning saws come in various shapes and styles. Most now have blades with teeth sharpened in both directions to cut on both the pull- and the push stroke. Larger teeth saw through tough wood more quickly. Longer blades provide more cutting surface but are also prone to break if twisted while cutting. Smaller-bladed saws are available with fold-up blades that can be transported long distances safely. Longer bladed saws often come with a scabbard that can be fastened to your leg for safe transport. When buying any tool, weigh the benefits of a high quality and durable tool with ease of carrying it and the risks of damaging or losing it in the field.
Although a single cut with pruners, loppers, shears, or saws, typically will not kill a plant, cutting can be valuable, even vital, in combination with other techniques to achieve effective weed control. It is often a critical as a stop-gap measure that controls seed production until more comprehensive approach to weed control can begin.
How to Use
Repeated cutting removes enough above-ground biomass and photosynthetic resources over time to exhaust and kill a plant. Stems (typically 3” or less but can be larger when a saw is used) are repeatedly cut low to the ground until the plant dies. Alternatively, the first cut can be made higher (at 1’-2’ above the soil) to encourage regrowth higher up and make re-cutting lower easier. Low recuts can be more effective but can result in multiple stump sprouts that are difficult to recut with hand equipment. Higher initial cuts are often preferred for large stands of shrubs (e.g., broom) and may expose a stem enough to allow plants to be removed subsequently by weed wrench. However high initial cuts should not be made if the site is not being revisited in the same season to recut or otherwise retreat stems. Shrubs and trees may need one to several cuts per growing season for multiple years to keep regrowth down and deplete carbohydrate reserves in belowground structures. Given that this technique relies on stopping seed production as well as growth of target plants, practitioners should make sure that seed production is also controlled in adjacent areas to prevent re-infestation. Woody vegetation that can sprout from roots should not be targeted with this technique unless extensive repeated follow-up cutting can be guaranteed. The size of the area that this technique is effective on depends on the size, availability, and reliability of the work force over time.
Thorny vines, such as Himalayan blackberry, are best controlled using long-handled loppers (or see Bladed Hand Tools BMP) in combination with follow-up manual removal or subsurface cutting. Biennials and herbaceous perennials that bolt (e.g., thistles) can be controlled by cutting bolting flowering stalks repeatedly. They will probably require multiple cuts in a single growing season to prevent flowering and often two years to kill plants. Depending on the species, cuts may stimulate regrowth (including root sprouts) that will need to be addressed, either by cutting or by another treatment method.
Cuts should be made straight across stems to avoid creating vertical spikes that could impale people, wildlife or livestock. Stems cut near public use areas should also be either cut flush to the ground or removed promptly with a weed wrench to avoid creating tripping hazards or opportunities for other injury.
Cutting is more effective when it is done in the dry season. For instance, some French broom shrubs cut in the summer under drought conditions have died after only a single cut. Loppers with ratcheting capability and telescoping handles are particularly useful for cutting broom species because long handles can allow the user to access to the central stem and ratcheting increases leverage.
Cutting shrubs and trees leaves behind a lot of biomass. Biomass can be stacked as brush piles where it will provide some habitat and decay slowly over years (but these piles can also become hotspots for invasive plants and should be monitored). In some settings, brush piles can be burned during the wet season to reduce fuel loading on the landscape if proper precautions are taken and air quality restrictions permit burning. In areas with high fire risk, where re-establishment of desirable vegetation could be impacted, and where biomass might impact visitor experiences, biomass should be either chipped or mulched on site or removed. On steep slopes, cut biomass can be repurposed for erosion control, especially when baled as fascines or chipped. Plant material can also be used to close social or access trails created by control work. If plant material contains seeds, it should be removed from the work site or treated so that seeds are inviable.
Gloves are very important to wear when using cutting tools. Choose gloves with rubberized palms to increase your grip and reduce the chance of getting blisters. All metal-bladed equipment should be well maintained, cleaned frequently and oiled to prevent rust form occurring on the metal surfaces. Clean off dirt and vegetative debris from tools, sharpen blades periodically, and disinfect them between species and project sites. A pocket file can be used to sharpen blades in the field. Oil blades and wooden handles periodically.
Special Tips
- In areas with strong browsing pressure, like from deer, mature shrubs may be cut below the browse line and deer will generally eat any new growth thereby reducing or eliminating seed production. This works particularly well on shrubs in the Rosaceae (Cotoneaster, Pyracantha, Crataegus).
- Target plants are easiest to find before the first cut. Mark sites and individual plants to minimize the chances that you will miss any when you return.
- Peel bark of stem bases to the soil line (or below) to reduce the chances of a shrub or small tree resprouting. This approach is especially useful for shrubs (e.g., broom) on steep slopes where manual removal with a weed wrench is dangerous and could promote erosion.
- Loppers can be purchased with telescoping handles, which can extend the reach to targeted vegetation. They can cut stems up to about 1½” in diameter but are most effectively used on smaller-diameter stems.
- Both loppers and pruners can be purchased with a ratchet feature that makes cutting easier. Presence or absence of a ratchet, gape size (how wide the blades open), sharpness, and length of handles all influence how large a stem can be cut. Bypass pruners are preferred for live stems because they cut tissue more cleanly and with less tissue damage. However, they are more prone to be damaged because the blades must fit closely and pruner blades can easily become misaligned if the user twists them or tries to cut stems that are too thick. This is especially true for bypass loppers because the long handles increase torque on the blades. For this reason, some practitioners recommend using the anvil form (especially for volunteer groups). Pruning saws and loppers can be purchased as pole saws for difficult-to-access plants.
- Consider painting tool handles with bright paint or tying them with flagging tape to minimize chances of losing them in the field.
- Find a safe and efficient way to carry your cutting tools in the field. See https://www.cal-ipc.org/resources/library/videos/tool-belt/ for toolbelt tips.
Optimal Conditions for Use
- Best used for woody-stemmed plants that have a limited capacity to resprout. Cutting is particularly effective on conifers, which typically cannot resprout (exceptions include junipers and redwoods).
- Also effective as a stopgap measure to stop seed production for one season.
- Most effective during lower rainfall years that increase the stress imposed on a plant by cutting.
- Timing cuts for late in the growing season when energy stored in roots is low can increase effectiveness of limiting resprouts.
Caveats
This technique requires long-term and consistent follow-up. In order to be effective, stems that have been cut must be recut regularly (as often as every few weeks) for multiple years to deplete resources, depending on the species.
While the tools used for cutting are easily transportable to remote locations, consistent follow-up is especially difficult at those sites because of the additional travel time involved to access target vegetation.
The biomass that accumulates from cutting can create additional fuels for wildfire, depress establishment of desirable plants, crease hotspots for weeds, and may be considered unsightly.
Regrowth and next generation recruits that are smaller and less apparent than adult target plants are more difficult to detect. As with most other weed control techniques, follow-up searches are critical if your goal is to eliminate a weed from an area.
This technique can result in the removal of nesting habitat for birds. Nesting bird surveys should be performed between Feb 1 and Aug 31 to mark any active nests to avoid before work. In shrubland habitat, consider replanting with desirable plant alternatives if you anticipate impacts to wildlife.
Repeated cutting in wetter environments is more labor intensive and will take longer to be effective because more resources are available to plants to resprout.
Potential Hazards to Humans, Environment, and Cultural Resources
Human safety. Low risk. When sawing, cut away from your body; when using clippers, keep fingers out of their path. Wear gloves to reduce chafing and the risk of potential cutting. Reduce risks of carpel tunnel and hand or wrist strain by using ergonomically correct tools and taking regular breaks during work activity. Identify and avoid poison oak!
Cultural resources.Low risk. Cultural resources are generally not impacted by this technique because it does not disturb the soil surface. Cultural resources located on the surface may be exposed by work.
Habitat. Low risk. This technique is minimally invasive to habitat. If dead plant biomass generated is not removed from the site it can be stacked away from waterways and in a manner that will minimally impact desirable vegetation. If mulched or burned there may be short-term impacts to habitat. .
Sensitive species.Low-moderate risk. Damage to wildlife and plants is a low risk with this technique if proper precautions are followed. Nesting bird surveys should be conducted before cutting during breeding season (generally Feb 1- Aug 31) to minimize damage to nesting habitat. Identify sensitive plants in an area in advance and avoid trampling or otherwise impacting them.
Erosion.Low risk. Since soil surface is generally not disturbed, risk of erosion is minor. Keep soil surface covered with litter or other vegetation.
Consider Combining with the Following Non-Chemical Methods
Repeated cutting can be used with other techniques that target emerging seedlings, such as flaming, hoeing, or manual removal.
Cutting is often used to make other techniques possible. For example, tarping, cutting subsurface structures, manual removal with a weed wrench, or grub-hoeing may require removing tall stems first.
Cutting can also be used as a one-time measure to shift the competitive balance from the target plant to that of co-occurring desired vegetation. This is generally (only effective for pines, palms, and other species that do not resprout.
Cutting can be combined with bark peeling (see Girdling BMP) to improve its efficacy.
Lastly, cutting is a useful way to remove seeds, canes that root at tips, and seed heads to prevent propagule dispersal in a project area, regardless of other techniques being used for effective control.
Don’t Use This Technique When/For
Repeated cutting should not be used as the sole technique on rhizomatous species because of the tremendous amount of sustained effort that would be needed to be effective. Some rhizomatous species will actively spread more when cut. Also, this technique should not be used on any stump- or root-sprouting woody species (e.g., tree of heaven if retreatment cannot be guaranteed) because single cuts may make later control more difficult if regrowth is not removed.
Supplementary Information
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References
DiTomaso, J.M, G.B. Kyser et al. 2013. Weed Control in Natural Areas in the Western United States. Weed Research and Information Center, University of California. 544 pp.
Milbrath, L.R., A. DiTomaso, J. Biazzo, S.H. Morris. 2016. Tolerance of swallowworts (Vincetoxicum spp.) to multiple years of artificial defoliation and clipping. Invasive Plant Science and Management 9:1-11.
Moore, Ken. 2009. Woody Plant Control with Ken Moore and the Wildlands Restoration Team – Santa Cruz, CA. https://www.cal-ipc.org/resources/library/videos/techniques-for-controlling-woody-plants/.
Parkinson, H., J. Mangold. 2010. Biology, Ecology, and Management of the Knotweed Complex (Polygonum spp.). Montana State University Extension. 19 pp.
Authors and Credit
Lead Author: Jutta Burger, Science Program Director, California Invasive Plant Council
Co-authors:
Pamela Beitz, Integrated Pest
Management Specialist, East Bay Regional Parks District
John Kenny
(volunteer); Dan Lubin, Environmental
Scientist, California State Parks
Susan Schwarz, President, Friends
of Five Creeks
Andrea
Williams, Marin
Municipal Water District (former)
Additional Contributors:
Ken Moore, Wildlands
Restoration Team
Tom Kelly, Executive
Director, KyotoUSA
Eric Wrubel, Biologist,
National Park Service
Efficacies
| Rating | |||
|---|---|---|---|
| Plant | Flowering Period | ||
| Winter | Fair | ||
| Spring | Fair | ||
| Summer | Fair | ||
| Fall | Fair | ||
| Multiple Seasons | Fair | ||
| None | Fair | ||
| Plant | Germination | ||
| Winter | Fair | ||
| Winter / Spring | Fair | ||
| Spring / Summer | Fair | ||
| Opportunistic | Fair | ||
| Plant | Palatability | ||
| Yes | No Information | ||
| No | No Information | ||
| Partial | No Information | ||
| Plant | Plant Growth Form | ||
| Grass | Fair | ||
| Forb | Fair | ||
| Shrub | Fair | ||
| Tree | Fair | ||
| Vine | Poor | ||
| Plant | Plant Type | ||
| Annual | Fair | ||
| Biennial | Fair | ||
| Perennial | Fair | ||
| Plant | Propagule Production | ||
| Low (<1000/square meter) | Fair | ||
| Moderate (1000–10,000/square meter) | Fair | ||
| High (>10,000/square meter) | Fair | ||
| Plant | Rate of Spread | ||
| High (doubling in <10 year) | Fair | ||
| Moderate (50–75% increase in 10 years) | Fair | ||
| Slow Rate (25% increase in 10 years) | Fair | ||
| Plant | Resprouting / Regenerative Capacity | ||
| Low | Fair | ||
| Moderate | Poor | ||
| High | Ineffective | ||
| None | Good | ||
| Plant | Seed Life | ||
| Short (≤3 years) | Fair | ||
| Moderate (4–10 years) | Fair | ||
| Long (>10 years) | Fair | ||
| Plant | Type of Reproduction | ||
| Seed | Fair | ||
| Vegetative | Poor | ||
| Seed & Vegetative | Poor | ||
| Plant | Type of Vegetative Reproduction | ||
| Rhizome / Stolon / Stem | Ineffective | ||
| Bulb / Corm / Tuber | Poor | ||
| Root sprout / Sucker / Crown sprout | Fair | ||
| Site | Existing Desirable Plant Cover | ||
| <10% | Fair | ||
| 10–25% | Fair | ||
| 26–50% | Good | ||
| 51–75% | Good | ||
| >75% | Good | ||
| Site | Ground Condition | ||
| Muddy | Fair | ||
| Smooth | Fair | ||
| Cobbly | Fair | ||
| Rocky | Fair | ||
| Site | Habitat | ||
| Marsh / Wetland | Poor | ||
| Riparian | Poor | ||
| Grassland | Fair | ||
| Shrubland | Fair | ||
| Woodland / Forest | Fair | ||
| Site | Level of Tolerable Disturbance | ||
| Low | Good | ||
| Medium | Good | ||
| High | Good | ||
| Site | Slope | ||
| Flat | Good | ||
| Moderate (10–40%) | Fair | ||
| Steep (>40%) | Fair | ||
| Site | Target Area | ||
| <40 square feet | Good | ||
| 0.001–0.01 acre | Good | ||
| 0.02–0.1 acre | Fair | ||
| 0.2–1 acre | Poor | ||
| 2–10 acres | Poor | ||
| 11–50 acres | Ineffective | ||
| 51–100 acres | Ineffective | ||
| >100 acres | Ineffective | ||
| Site | Targeted Invasive Plant Cover | ||
| <1% | Good | ||
| 1–10% | Good | ||
| 11–25% | Fair | ||
| 26–50% | Fair | ||
| 51–75% | Poor | ||
| >75% | Poor | ||
| Site | Vehicle Accessibility | ||
| Roadside | Good | ||
| <100 feet from road | Good | ||
| 100–1000 feet from road | Good | ||
| >1000 feet from road | Good | ||
