Mature Wintergrass with seeds

How To Kill Winter Grass

Winter grass is a bright, light green grass with fine leaves that infests lawns throughout winter. Apart from the unsightly appearance, winter grass will continue to spread and cause damage to a lawn for as long as it remains untreated.

The root system of Wintergrass is a mass of very fine, white, spider web like roots that can easily invade and choke out the root system of a lawn. Even when the Wintergrass is not evident throughout most of the year, its root system continues to deprive lawns of space to set down its own roots, causing the lawn to continue to be nutrient deficient and unhealthy.

Even after successful treatment, the root system of Wintergrass will remain for many years as it degrades at a slow rate. If a lawn was heavily infested, Coring should be considered as a means to remove some of the unwanted root system and allow the lawn extra space to set down new roots in order to recover at a much faster rate.

Winter Grass Method Of Spreading

Wintergrass spreads by very fine seeds that become evident towards the end of Winter.

Cultural Management:
Regular mowing will not necessarily control this weed because the seeds are usually too fine to be removed completely, a percentage will always be left behind to continue the growth of infestation the following year.

Wintergrass - Most Prevalent

Germination - April
Prevalent - May September

Winter Grass Treatment Method

Wintergrass is treated with a poison that reacts with its root system. After the herbicide is applied to the lawn, it is usually lightly watered in so the poison reaches the roots to begin working.

Winter Grass Pre-emergent Treatment

The very best treatment time is when the weed is pre-emergent, which is after the weed has germinated, but before it can be seen in the lawn. Sounds tricky but its not, if you had Wintergrass last year, it is guaranteed you will have it again this year, simply apply the treatment after this years germination, either April or May.

Late Treatment Of Winter Grass

Treatment must be timed correctly for when Winter Grass is actively growing and still young, when the weed becomes too mature, the poison will no longer work, and will need to be applied again the following year. After June, the success rates for eliminating the weed will begin to reduce.

When Its Too Late To Treat Winter Grass

If you missed this years treatment window, go straight to next years calendar and mark down May as a reminder to treat Wintergrass pre-emergent.