Invasive Weed Management
* Price and difficulty of install depends on the weed and the control method used.
MATERIALS
- Herbicides*
* If herbicides are needed: Read label – Herbicide must be rated effective for targeted weed. Certain herbicides must not be used near water, around desirable woody vegetation or under other circumstances as described on label.
TOOLS
- Shovel
- Weed trimmer/mower
- Gloves
Possible Items Needed:
- Weed wand, hand sprayer, back-pack sprayer
Invasive weeds can spread quickly if left unmanaged. The most effective way to control weeds, noxious and otherwise, is to integrate several different control methods targeted to the specific species, size of the population and land use of your property.
To learn more about identifying invasive weed types,visit the Vegetation section in Chapter 2
The four types of weed-control methods are:
1. Cultural
The most cost-effective and easiest way to control noxious weeds is to prevent their establishment. Prevention techniques include:
• Before entering your land, wash construction vehicles coming from another, potentially weed-infested, location.
• Use only weed-free mulch.
• Use only seeds free of weeds.
• After ground disturbance, quickly revegetate the site. Establishing desirable native species first is an effective control method.
2. Mechanical
Mowing or pulling weeds can be effective for some noxious weeds, especially if the populations are small. Mechanical methods are not as effective for noxious weeds with extensive root systems, although a combination of mechanical and chemical control can be successful.
3. Biological
Grazing can control noxious weeds, especially during specific stages of the weed’s life cycle. Some noxious weeds have specific pests that can effectively control that species. Contact the Colorado Department of Agriculture (CDOA) or your county weed manager for information on specific pests. Note: all biological methods help control the amount of a noxious weed species, but generally do not eradicate them.
4. Herbicides
Herbicides can effectively control noxious weeds, but care must be taken to prevent damage to desirable plants, humans, livestock or wildlife. Use only the herbicides recommended by the CDOA or your county weed manager. When spraying near a stream, only use herbicides rated as safe near water. Strictly follow the directions on the herbicide’s label.
Combining these different methods minimizes potential harm from overuse of chemicals that could damage your property or your neighbors’ property. Working with your neighbors or homeowner’s association to develop an integrated weed control plan is an effective way to prevent weeds from invading or re-invading your land.
To determine what is the best control method for the infestation on your land, first assess the type and size of the infestation on your land with these questions:
1. What type of weed(s) do you have?
Some (such as annuals) can be controlled by simply pulling the weeds, others (such as ones with extensive root systems) need repeated mechanical treatment and/or herbicide treatments.
2. What are you using your land for?
Some weeds (especially non-noxious weeds) are not detrimental in small patches or for certain land uses. For example, scattered dandelions are not harmful in riparian woodlands or native meadows. However, extensive dense patches may decrease grazing productivity or may not be considered aesthetically pleasing on a lawn.
3. How extensive is the infestation?
A few plants can be removed by pulling even if it must be done several times. Large patches may require repeated mechanical treatments and/or herbicide applications.
4. Does the infestation extend to your neighbor's property?
If the weed infestation occurs over several properties, then a community wide control effort may be needed to prevent re-invasion. For releasing biological control agents, it may be most effective to coordinate releases with surrounding neighbors.
5. Are the weeds near water?
Herbicide use should be limited because they can detrimentally effect water quality. If possible, other types of control methods should be used near streams and other water bodies. If herbicides are the most effective way of controlling the weed population on your property, then you must use an herbicide rated as safe near water.
6. Is the infestation near desirable woody vegetation?
Many herbicides will also kill nearby shrubs and trees. Read the herbicide label to ensure that it can be used near non-targeted woody vegetation or use another method such as mowing/pulling.
7. Is the infestation near a rare plant?
Use best management practices and avoid herbicide applications near populations of rare plants as described in the Colorado Department of Agriculture – Recommended Best Management Practices for Managing Noxious Weeds on Sites with Rare Plants.
8. After removal - is follow-up needed?
Revegetating with an appropriate seed mix is one of the best methods to prevent re-infestations by the removed weed or invasion by other weeds. Frequent monitoring and quick removal of individual weeds prevents extensive and costly weed control efforts later.