How to Get Rid of Guildford Grass in Your Lawns

Guildford Grass is commonly found across southern Australia, including Victoria, South Australia, Tasmania, parts of New South Wales and southern Western Australia.

It might appear delicate thanks to its onion-link tubular leaves and pink, star-shaped flowers that bloom in Spring, but the reality is that its bulbous underground corm can lay dormant for extended periods of time, which allows it to survive cultivation like mowing and makes it difficult to kill.

Guildford Grass is particularly active during the cooler months, typically germinating in Autumn, growing through Winter and flowering in Spring before dying off in early Summer. It can invade all major warm-season turf varieties such as Buffalo, Couch, Bermuda, Kikuyu, and Zoysia, but it tends to be most prevalent in thinner, stressed lawns.

It spreads both through seed and by multiplying its underground corms, making early intervention critical.

Manual Removal

Controlling Guildford Grass in Australian lawns can be a challenge due to its underground corm. Manual removal is an option for small patches, but it’s crucial to dig out the entire corm — simply pulling the leaves out will not remove the plant and may even cause it to multiply.

Removing the weed when the soil is moist gives the best chance of extracting the entire plant. Regular mowing can help reduce seeding, but won’t stop the weed from returning year after year.

Using Herbicides

For a more proactive approach, selective herbicides can be used. Commonly available broadleaf herbicides are not effective against Guildford Grass, however Duke 100 WG is registered to control this pesky weed, as well as several other hard-to-kill grassy and broadleaf weeds.

Duke cannot be used on all grass types though, and while it’s safe for most warm season grasses including Buffalo, Kikuyu and Couch (and Couch hybrids like Santa Ana, TifTuf or Iron Cutter Elite Hybrid Bermuda), it’s not safe to use on Zoysia, Queensland Blue Couch, or cool season varieties like Fescue, Rye or Bent Grass. 

To ensure efficacy on the first application of any herbicide, it’s recommended to apply in conjunction with a surfactant like Wetter 600 for improved adhesion to the leaf.

When using chemical treatments, always follow manufacturer instructions when it comes to necessary protective equipment and safe re-entry times for humans and animals. Apply on a dry day with minimal wind to prevent drift onto desirable grasses.

Natural Remedies

Guildford Grass can be removed from your lawn without the use of chemicals by hand-pulling the weed. Natural herbicides will be almost entirely ineffective against Guildford Grass.

To prevent Guildford Grass from returning, applying a high-quality pre-emergent herbicide is a proactive solution. Pre-emergents work by creating a barrier in the soil that inhibits seed germination, effectively stopping weeds before they establish.  

A good pre-emergent herbicide, such as those containing Prodiamine (such as Spartan in liquid form, or Onset GR in granular form) or Oxadiazon (like Echelon Duo or Oxafert), offers up to six months of protection against a broad range of invasive weeds.  

This long-term approach not only reduces the need for repeated manual or chemical interventions but also contributes to a healthier, more resilient lawn with less pressure from invasive weeds.

Whether you’re looking for a quality pre-emergent to minimise the risk of Guildford Grass invading your much-loved lawn, or you need a post-emergent herbicide to control a Guildford Grass outbreak, you’ll find all the supplements and chemicals you need to keep your grass in top shape at the myhomeTURF Online Shop; home to hundreds of market-leading products that ship Australia-wide.