When to Apply Pre-Emergent Herbicide in Flower Beds & Mulch Areas
Late March - Early April is a great time to apply pre-emergent as long as you prepare the bed first. Make sure the bed is clean of debris and dead plant material with exposed mulch or dirt for best results.
Landscape bed pre-emergent products are a great way to cut down on the amount of annual and perennial weed seeds in flower beds. While these herbicides are effective against many weeds, they are not universal solutions. Always consult the product label before use, as application restrictions vary by ornamental plant and some formulas require specific techniques for safe, effective results.
Using pre-emergent herbicides is not a one and done treatment but can save you a lot of time in summer when weeds are at their peak. Pre-emergent prevents weed seeds from growing and maturing by inhibiting the root system development of the young weed seedling. This kills it before it matures. If you have existing weeds you may want to apply a post-emergent herbicide, such as RoundUp.
Pre-Emergent Recommendations:
Mulched Flower Beds & Residential Landscape Beds
Treflan DG Pro (Trifluralin)
Tricept 2.5 DG (Trifluralin & Isoxaben) - similar to Snapshot
Prodoxaben G (Prodiamine & Isoxaben)
Mulch Beds & Commercial Properties
Sureguard EZ (flumioxazin)
Flumishield SC (flumioxazin)
Surmise Pro XT
Bare Ground
Pramitol 25E
Surmise Pro XT
These products should be applied every 4-5 months, depending on which brand you are using. If mulch is used and annuals are planted, a pre-emergent application should be done after mulching.
We recommend applying 2-3 times a year. The first application in late March to Early April and another application in June or July to get you through the season. You can also apply a fall application for winter annuals in September or October - this will help reduce some early season weeds for the following year.
All applications need to be watered in, therefore you can apply when rain is in the forecast or even on a rainy day. The rainwater helps activate the herbicides and get them washed into the soil where they do their best work.
Once they are watered in, they create a barrier thus preventing weed germination. If the barrier is disturbed from digging holes to plant there is a chance it will no longer be effective.
