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Publication #HS1170

Nonchemical Weed Control for Home Landscapes and Gardens1

Andrew MacRae, Nathan Boyd, and Marina D'Abreau2

A weed in a home landscape is defined as a plant in an undesirable location that is unusually persistent. This may include an undesired plant or a desired plant that has outgrown its original space or desired boundry. Numerous strategies can be utilized as part of a home weed control program. Many homeowners and gardeners are interested in managing weeds in their landscapes and gardens without the use of chemical herbicides. A nonchemical approach is possible but requires more planning and effort to be successful. There are multiple options described below and homeowners are most likely to achieve the desired results if they incorporate more than one approach into a management plan. There are many benefits to nonchemical approaches, including lower risk of damage to non-target plants, decreased costs, and the opportunity to more frequently scout the landscape for potential problems. To adequately manage weeds without herbicides requires frequent and consistent monitoring. Homeowners should take the time to walk through their property on a regular basis and identify problematic areas or weeds that need to be addressed. A basic knowledge of the weed species present around the home will help identify the best management approach. In addition, home owners may want to consider modifying areas of their landscape where weeds are a persistent problem. It is important to maintain weed populations at the lowest level possible to prevent re-infestation. Established perennial weeds produce vegetative reproductive parts such as roots, rhizomes, stolons, or tubers. These structures facilitate rapid spread, make them difficult to kill, and enable quick population rebound. Annual weeds do not produce vegetative reproductive parts but will flower and produce large numbers of seeds that may greatly increase future problems. For example, annual grasses are capable of producing several thousand seeds per plant, while some annual broadleaf weeds are capable of producing tens of thousands of seeds per plant. Both annual and perennial weeds are typically easier to control when they are small and prior to flowering. Timely and routine monitoring and weed management are essential to maintain low levels of troublesome weeds.

Below are some of the most common options for weed control and descriptions of their pros and cons.

Hand Pulling

This strategy is a low-tech option that provides exercise and the opportunity to frequently scout the landscape for other potential problems. Pulling weeds can be very effective in some situations, such as when weeds are growing close to sensitive plants. Hand pulling can be strenuous, and some weed species are extremely difficult to pull by hand. It is best to pull weeds while they are relatively small. Hand pulling of larger weeds is difficult and can result in uprooting of nearby annual plants. Hand pulling is most effective if employed on a regular basis so that weed populations in landscape beds and gardens are kept to a minimum. In the case of perennial weeds that have an extensive root system, numerous sessions of hand pulling will be required before effectively exhausting the stored energy in the root systems. Until that time, the perennial weeds will continue to grow from their roots. A good pair of gloves and some knee pads will make this option easier and more comfortable.

Cultivation or Tillage

This method utilizes a tool or implement to physically remove or destroy weeds. The use of a hoe, shovel, trowel, weeder, or knife is adequate for cultivation of small- to moderate-sized areas. For larger areas, tillage with a rototiller or similar equipment may be more efficient. Cultivation or tillage is often more effective at removing weed species that are difficult to remove by hand, such as perennials with an extensive root system. These perennials will sprout again, but with successive cultivation it is possible to exhaust the food reserves in the roots. As with hand pulling, cultivation or tillage is most effective if employed on a regular basis so that weed populations are kept low. It also provides exercise and the opportunity to frequently scout the landscape for other potential problems. A rototiller should never be used around existing trees, but it is a great way to incorporate soil amendments such as organic matter, fertilizer, and lime

Mulch

One of the many benefits of mulching in home landscapes and gardens is the suppression of weeds. A 2–3 in. layer of mulch is adequate for weed suppression in most situations. In fact, mulch depths over 3 in. may actually be detrimental to plant health because of potential decreases in soil oxygen. Mulch provides a clean, finished look to landscape beds and paths. Mulch may also help to moderate soil temperatures, maintain soil moisture, and provide plant essential nutrients. There are numerous types of mulches available for use in home landscapes and gardens. For more information on mulch, visit http://edis.ifas.ufl.edu/topic_mulch.

Landscape Fabric

It is increasingly popular to use landscape fabric to help prevent the emergence of weeds in planting beds. This fabric can also be used in the home garden. While potentially costly, these fabrics can suppress weeds for two or more years'. It is important to note that landscape fabrics suppress many weed species but may increase the populations of others. Nutsedges (those weeds with a triangular stem) have a sharp growing point and can penetrate through the thinner styles of landscape fabrics. If weeds are coming through the fabric, it is important to hand pull them as soon as possible before they establish a foothold and become difficult to control.

Flaming

Flaming uses the high temperatures created by a propane burner to burst the cell walls of plants. Burning the plant tissue is not necessary as plants will quickly dry out and die if their cell wall is destroyed. A quick way to tell if a weed is going to die from the flame treatment is to let the weed briefly cool and then press your thumb to the leaf. If it leaves a thumbprint or smudge, the treatment succeeded in causing the plant cells in the leaf to rupture. This weed control method will only control above-ground portions of a plant and will not adequately control perennial plants or grasses.

Conclusion

It is important to note that flaming can be dangerous to the operator and desirable plants. Never burn around the base of desired plants as the heat can damage shallow roots orthin-barked stems. Do not apply flame to landscape fabric, dry mulch or any other dry, flammable material as it may start a fire Be careful around irrigation systems and be careful not to melt any plastic or rubber portions of a soaker hose or garden hose.

Each strategy for nonchemical weed control has pros and cons associated with it. Most of these strategies can be used alone or in conjunction with each other. In fact, these strategies can even be incorporated into a weed management program that includes the use of chemical herbicides. A successful weed management program for the home will use more than one technique. If a person is persistent, a good weed management program will reduce weed populations over time, making each successive season easier to maintain weed free.

Footnotes

1.

This document is HS1170, one of a series of the Horticultural Sciences Department, UF/IFAS Extension. Original publication date April 2010. Revised July 2013.Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Andrew W. MacRae, former assistant professor; Nathan Boyd assistant professor, UF/IFAS GCREC, and Marina D'Abreau, residential horticulture agent, UF/IFAS HCES.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.