How to Treat Carpetweed & Blanketweed

Treating Carpetweed

• 1

  Set your lawn mower at its highest level and mow over the affected area during late spring.

• 2

  Apply post-emergent herbicide as soon as mowing is complete. This allows the chemical to penetrate the weeds more efficiently. Select a time when no rain is anticipated for at least the next 48 hours and put on protective gloves before beginning the application. Consult package directions to determine the correct way to mix the herbicide solution, as this may differ between brands.

• 3

  Avoid mowing the lawn too closely for the remainder of the growing season after treating for carpetweed, as this may encourage remaining tap roots to resprout. The ideal mowing height depends upon the type of turf in your lawn. For example, tall fescues can be cut no shorter than 2 1/2 inches, while Kentucky bluegrass can be trimmed back to a height of 2 inches.

• 4

  Water the lawn regularly to prevent bare spots, which provide an ideal location for new carpetweed plants to grow.

• 5

  Treat previously affected areas with pre-emergent herbicide during early spring. This keeps carpetweed seeds that were dispersed during the prior season from sprouting. Again, read and follow herbicide package instructions carefully.

Treating Blanketweed

• 6

  Submerge a 5- to 6-foot-long sturdy stick into the water and use a twirling motion to remove as much of the blanketweed as possible.

• 7

  Add a liquid barley straw extract to the water, at the frequency and rate indicated on the instructions, which discourages the growth of algae. It is generally applied each week, at a rate determined by the size of the pond. This may vary between products, however, so read package directions carefully.

• 8

  Install a pond pump and filter to prevent stagnant water, which provides the ideal growing conditions for blanketweed.

• 9

  Treat the water with algicide if the blanketweed persists. This frequently involves treating only half the water at a time and making applications once every two weeks. Read and follow the application instructions carefully, as instructions about the amount of water to treat and the frequency of treatment may vary. Too much algicide may harm fish in the pond or passing animals that drink the water.