Management Alternatives

• Herbicide
• Grazing
• Biological Control
• Mechanical
• Flooding
• Revegetation

Herbicide ¹

Basal bark treatment. For scattered individual shrubs (see Figure 7), a single low volume basal bark treatment using a 30% solution of trycolpyr (Garlon 4 ^® or Remedy ^®) mixed with a commercially available basal bark oil, number one or two diesel fuel, or kerosene is highly effective and practical. Spray until thoroughly wet, but not to the point of runoff, the entire circumference of all stems including the root collar area from the ground up to 18 inches. This treatment can be applied anytime including winter, except when the bark is frozen, when snow or water prevent spraying to the ground line, or when the stems are submerged in water. It may take one or two years for the herbicide to move throughout the plant, especially the roots, and for plants to die. Triclopyr is labeled for non-irrigation ditch banks, seasonally dry wetlands, and transitional areas between uplands and lowlands where surface water is not present except in uneven isolated pockets. It cannot be sprayed on open water or irrigation ditch banks currently used to carry irrigation water. Read and follow all label instructions.

Cut stump treatment. Where it is practical to cut saltcedar stems using a saw or loppers, applying tryclopyr (Garlon 4 ^®, Garlon 3 ^®, or Remedy ^®) or glyphosate (Roundup ^®) directly to the cut stem up to an hour after cutting will prevent re-sprouting. Herbicide should be applied undiluted to wet the wood and surrounding cambium around the entire circumference of the cut stump. Cut stump treatments can be applied any time of year except when stems are frozen or when plants are under water stress during late summer. To prevent regeneration from sprouting, cut, and then dispose of stems and branches by burning or chipping for fuel.

Foliar application. Foliar herbicide application to control saltcedar is most practical where there is a dense stand of saltcedar with a solid canopy or where basal bark or cut stem treatments are not practical. Imazapyr (Habitat ^®) at a rate of 2 quarts product per acre or imazapyr plus glyphosate (1 quart plus 1 quart per acre) are the most effective foliar sprays for controlling saltcedar. A non-ionic surfactant in the spray solution at 0.25% by volume is needed when using imazapyr. The best control is obtained when applied in late summer or early fall (August and September). For spot treatment, a 1% solution of imazapyr with surfactant can be used. Imazapyr is labeled for riparian use and can be sprayed directly in water. However, there are many restrictions for water applications and the label instructions should be carefully followed.

Grazing

Cattle, sheep and goats will graze saltcedar, but it is considered nutritionally poor. Cattle only eat young sprouts early in the spring. However, livestock tend to select cottonwood and willow over saltcedar. Aggressive grazing by confined sheep or goats may provide some control, but suckering may increase the density of the canopy. Boer goats have been used to graze saltcedar. In one field study conducted in Utah, goats grazing along a shoreline four times throughout the summer reduced the biomass of saltcedar. This type of intensive grazing has been recommended as a treatment to reduce the amount of foliar herbicide applied. Herbicide effectiveness increased when herbicides were applied after the grazing treatment.

Biological Control

Investigations to determine the efficacy and feasibility of saltcedar biological control were initiated in 1987 by USDA-ARS researchers in Temple, Texas. Biological control of saltcedar (like other noxious weeds) is appealing because it represents a highly selective, low cost, sustainable management approach when effective agents successfully establish, proliferate, and efficiently reduce target populations. However, the release of saltcedar bio-control agents remains somewhat restricted due to the perceived threat posed to indigenous wildlife, specifically the nesting resources of a threatened southwestern sub-species of the willow flycatcher (Empidonax traillii extimus). The willow flycatcher became habituated to nesting in saltcedar in locations where cottonwood, the flycatcher’s conventional nesting tree, had become locally extinct. Biological control is a desirable control strategy for saltcedar because target removal is more gradual and highly selective than other methods - this approach is thought to be a good way to facilitate the re-establishment and availability of non-saltcedar alternatives for wildlife food and shelter resources.

The saltcedar leaf feeding beetle, Diorhabda elongata Brullé subspecies deserticola Chen (Coleoptera: Chrysomelidae), originates from northwestern China and eastern Kazakhstan. Larval and adult stages of the beetle feed primarily on saltcedar leaves; occasional feeding on the epidermis of twigs and first-year shoots will also cause the tip of the twig/shoot and associated foliage to desiccate and fall off. The beetles prefer to feed on young foliage over mature leaves. Diorhabda is reported to have successfully established and controlled saltcedar in Lovelock, NV. Preliminary results suggest that Diorhabda can defoliate up to 162 ha of saltcedar three years after initial release under ideal conditions. However, successful establishment and control of saltcedar in Montana has been complicated by a number of factors. Early indications suggest that either biotic interference (predation) or environmental incompatibility (drought or springtime flooding) may be the primary factors impeding Montana releases of this agent, especially on saltcedar infestations along the Fort Peck shoreline.

This agent is not yet widely available for release in Montana. Current efforts are underway to establish insectaries throughout saltcedar-affected areas for the purpose of fostering the rapid growth of Diarhabda populations so that surplus agents can be collected for local re-distribution. Currently, any non-research releases of this agent in Montana must be made and annually monitored according to protocols developed by USDA-APHIS-PPQ.

Mechanical

Mechanical treatments including plowing, mowing, cutting, chaining and burning are not effective when applied alone because saltcedar readily re-sprouts from roots, root crowns, and stems after treatment. Follow-up treatments are needed to remove root crowns and new growth.

Flooding

Where water levels can be controlled in reservoirs and stock ponds, prolonged inundation for over three months may reduce saltcedar populations. Cottonwoods and other native vegetation are also killed by prolonged flooding and re-vegetation of desirable plants may be needed to prevent re-establishment of saltcedar or other weeds after flooding. Natural flooding cycles on free-flowing waterways are believed to reduce saltcedar establishment by scouring establishment sites free of seedlings, washing away deposits of accumulated salts, and clearing large accumulations of the highly saline leaf litter. Manipulating dam releases to restore natural flows on controlled waterways may favor native riparian plant establishment over establishment or re-establishment of saltcedar. Saltcedar seedlings five weeks old or younger are more susceptible to summer flooding than older saltcedar plants.

Revegetation

Revegetation of riparian sites can be used to prevent saltcedar establishment and to reduce re-establishment after control procedures are applied because saltcedar is not shade tolerant. To prevent saltcedar invasion, native perennial plants adapted to site hydrologic conditions should be established to minimize exposed bare soil during periods of moisture availability. To reduce re-establishment of saltcedar from root sprouts, trees, shrubs, and herbacious plants should be used to provide an inhospitable shading canopy. Guidance on seeding and planting techniques can be found in the NRCS Field Office Technical Guide (FOTG), Section IV, Practice Standards and Specifications:

• Riparian Forest Buffer (Code 391) and Riparian Herbaceous Cover (Code 390)

State and area resource specialists can help determine the most appropriate, site-specific species mix, timing of seeding or planting, and seeding or planting methods. Where herbicides have been applied, chemical carryover should be assessed prior to planting permanent vegetation.

¹ Any mention of products in this publication does not constitute a recommendation by the NRCS. It is a violation of Federal law to use herbicides in a manner inconsistent with their labeling.

< Back to Ecology and Management of Saltcedar

Last Modified: 08/21/2008