If there are obvious patches of grass that differ in colour, texture or height to surrounding fine turf, then you probably have coarse grass in your lawn. Identifying the type of coarse grass you have isn't essential, but it might help you decide if you want to keep or remove it and, if you chose to remove it, how best to do so. The descriptions and images below will help you identify three of the most common coarse grasses:  

Annual meadow grass (Poa annua) is a very common,

A native plant is one that originated or arrived naturally in a particular place without human involvement. In the British Isles, native plants are those that were here during the last ice age or have arrived unaided since.

Perennials are plants that live for multiple years. They come in all shapes and sizes and fill our gardens with colourful flowers and ornamental foliage. Many are hardy and can survive outdoors all year round, while less hardy types need protection over winter. The term herbaceous perennial is used to describe long-lived plants without a permanent woody structure (they die back to ground level each autumn), distinguishing them from trees, shrubs and sub-shrubs.

perennial

Rhizomes are creeping swollen root-like structures that are actually adapted stems. Roots, stems with leaves and flowers are produced along its length. See plants such as Anemone nemorosa, bamboo, canna, border iris.

rhizomes

Many coarse grasses, such as the three above, are

A native plant is one that originated or arrived naturally in a particular place without human involvement. In the British Isles, native plants are those that were here during the last ice age or have arrived unaided since.

• Caterpillars of gatekeeper butterflies feed on annual meadow grass and couch grass. 
• Caterpillars of speckled wood butterflies enjoy couch grass and Yorkshire fog.  
• Caterpillars of the small skipper butterfly and wall brown butterfly also feed on Yorkshire fog.  
• Garden birds feed on the seeds of coarse grasses. Annual meadow grass is particularly valuable as a source of winter food for finches. 

© Shutterstock

A gatekeeper butterfly

© Shutterstock

A small skipper butterfly

Here are our answers to your most common questions about dealing with coarse grasses in lawns:    

How

Invasive plants are those that grow vigorously, spread rapidly and can out-compete other plants. Native, non-native and cultivated plants can all be invasive.

invasive are coarse grasses?  

Coarse grasses use a few methods to increase their spread. Annual meadow grass quickly colonises bare patches of fertile soil by seed. Its success in lawns is due to its ability to flower and seed, below the height of mower blades, year-round. Wind, water, animals or human activity can spread the seed.  

Some coarse grasses, such as Yorkshire fog, also spread by runners (rooting stems) that grow outwards from the main clump. If these grow over bare soil, or into an area where fine grass species are weak or sparse, they will send down roots, increasing the size of the clump.  

Unlike the others, couch grass spreads primarily by

Rhizomes are creeping swollen root-like structures that are actually adapted stems. Roots, stems with leaves and flowers are produced along its length. See plants such as Anemone nemorosa, bamboo, canna, border iris.

Do I need to get rid of coarse grasses in lawns?    

No – allowing course grasses to grow in your lawn is a great way to boost the

The variety of living organisms (plants, animals, fungi and microorganisms) in a particular environment. Boosting the biodiversity of your garden has many benefits, including supporting wildlife, improving soil health and reducing the likelihood of pest and disease problems.

Coarse grasses add interest to meadows and species-rich lawns 

What is the easiest way to kill coarse grasses?    

If you have coarse grasses growing in your lawn and they cannot be tolerated, there are methods of controlling them:  

• Improve the health of your lawn – coarse grasses are less able to establish in dense, healthy lawns. Follow a programme of lawn maintenance in spring/summer and autumn to boost the vigour of your lawn. If patches of your lawn are struggling, overseed with a mix to suit the growing conditions.  
• Mow regularly – this will prevent some of the taller coarse grasses flowering and setting seed. Fine grasses are better adapted to tolerate regular cutting, whereas it will weaken coarse grasses. Use a collection box to remove the clippings, which may include coarse grass seed.  
• Avoid frequent watering – watering little and often during dry spells benefits coarse grasses, like annual meadow grass, that have shallow root systems. As lawn grasses are generally drought tolerant, there is no need to water an established lawn; even if it becomes brown during hot, dry weather, it will usually recover following a decent amount of rain. 
• Fork out plants – insert a hand fork under the main clump or rooted sections of stem and lift out the roots. This is a good, easy option for quick results on small areas of lawn. September is a good month to remove coarse grasses by hand, as it will reduce the population before winter (a season when they can thrive) and you can re-seed patches of bare soil straight away.    

Should I use weedkiller?   

No – selective lawn weedkillers are not effective on coarse grasses and non-selective weedkillers will kill all grass species, including those you wish to grow. As non-chemical control methods are effective, even if time-consuming on large lawns, there is no need to use a weedkiller.  

For more information, see our page on Weeds: non-chemical controls.