Annual trampweed, scientifically known as Facelis retusa, is a common broadleaf weed often encountered in various landscapes. This plant is a winter annual, meaning its life cycle begins in the fall, it grows through the cooler months, and then produces seeds before dying as temperatures rise in late spring and early summer. Understanding its characteristics and managing its presence can help maintain desired plant growth in your surroundings.
Identifying Annual Trampweed
Annual trampweed is a low-growing plant with a spreading habit, often forming colonies or mats that can extend across the ground. Its freely branching stems trail along the surface, reaching up to 30 centimeters (about 1 foot), and are covered in white, woolly hairs, as is the foliage. The leaves are narrow, arranged alternately along the stem, and often lack petioles. Their upper surface is dull green, while the lower surface is densely covered with white, long hairs. Each leaf is wider at the tip, tapering towards the base, and often ends with a tiny sharp point or an indented apex.
The flowers of annual trampweed are small and inconspicuous, appearing as white or sometimes purple disc flowers. These flower heads are clustered at the ends of the branches. The plant’s seed production in the spring creates fluffy, white, dandelion-like seed heads. These seeds have feathery bristles that enable effective wind dispersal, allowing them to spread widely and giving affected areas a “snowy” or “cottony” appearance.
Understanding Its Impact
Annual trampweed is an undesirable plant due to its competitive nature and prolific seed production. This weed rapidly colonizes bare or disturbed areas, outcompeting desired vegetation for essential resources. It commonly establishes itself in lawns, gardens, roadsides, pastures, and sandy fields, thriving in areas with low fertility or drought stress. Lawns that are thin or poorly maintained are particularly susceptible to invasion.
Once established, annual trampweed competes for water, nutrients, and sunlight, hindering the growth and vigor of turfgrasses and other cultivated plants. Its prostrate growth habit makes it difficult for turf to establish a dense canopy, allowing the weed to continue its spread. The plant’s ability to produce wind-dispersed seeds contributes to its rapid spread and makes it a persistent challenge.
Controlling Annual Trampweed
Managing annual trampweed involves preventive measures, manual removal, cultural practices, and, when necessary, chemical control. Preventing its establishment is often the most effective approach. Maintaining a healthy, dense lawn or garden through proper care significantly reduces the opportunity for annual trampweed to germinate and establish.
This includes regular soil testing to ensure appropriate pH levels and nutrient availability, along with applying the correct fertilizer at optimal times. Proper watering practices, such as providing about one inch of water per week through deep, infrequent irrigation, encourage robust plant growth that outcompetes weeds. Setting your mower to the appropriate height for your turfgrass species helps maintain a thick canopy, shading the soil and inhibiting weed seed germination. Applying a two to three-inch layer of organic mulch in garden beds suppresses weed growth by blocking sunlight and creating a physical barrier. Establishing a dense planting of desirable species also helps shade the soil and prevent weed emergence.
For existing plants, manual removal is an option, particularly for smaller infestations. Hand-pulling is effective, especially before the plant produces seeds. If using a lawnmower, attaching a bagger can help collect the fluffy seeds and prevent further dispersal. For larger areas, tilling or hoeing can disrupt the weed’s growth and expose its roots and seeds to drying conditions. Pruning annual trampweed from early to late spring can help manage its growth and reduce seed production.
Chemical control methods can be considered, though timing is important. Pre-emergent herbicides can be applied in the fall, ideally when temperatures begin to cool, to create a barrier that prevents weed seeds from germinating. Post-emergent broadleaf herbicides are most effective when applied from November through February, before the plant produces its seed heads in early summer. Common options include 3-way herbicides containing active ingredients like 2,4-D, dicamba, and mecoprop. Always consult product labels for specific application rates, safety guidelines, and suitability for your turfgrass type, and consider contacting local extension offices for tailored recommendations.