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Nutgrass is also known in various parts of the world as sedge grass. But no matter where in the world you garden, it can be a persistent and frustrating weed. It is recognised as one of the world's most invasive weeds!

It is also sometimes known as coco grass, java grass or ground almond. Its resilient nature and aggressive growth make it a challenge in gardens and lawns but the following detail (and video) will help you manage it should it make its presence known in your garden.

A word of warning; to remove it completely, may not be easy - in fact, it is hard and prolonged work, but you can get it to the point where you have got it controlled and being managed. So don’t despair! Be encouraged by this.

What is Nutgrass

Nutgrass, is a perennial plant that belongs to the sedge family. It is characterized by its triangular stem, lighter green colour, and distinctive flower head. Unlike traditional grasses, nutgrass mainly reproduces vegetatively by tubers and rhizomes, and it is this reproductive method that enables it to spread rapidly and form dense colonies.

A key challenge in managing nutgrass is its ability to thrive in various soil types, including moist and poorly drained areas as well as soils that are nutrient depleted, but as discussed a bit later, this can also be one factor that can be used to control it.

Nutgrass flowering

The Problems with Nutgrass

Nutgrass poses several challenges to gardeners. Its rapid growth can quickly overtake desirable plants, competing for nutrients, sunlight, and water. Additionally, nutgrass is resistant to many common herbicides, making traditional weed control methods less effective. In lawns, the presence of nutgrass can create an uneven and unsightly appearance. 

Furthermore, its tenacious rhizomes make complete eradication a very difficult task. To effectively manage nutgrass, you will need to target both the above-ground foliage and the underground rhizome system - removing just the above ground foliage will not be effective and perhaps even make your nutgrass problem worse.

Nutgrass in Lawn

Effective Nutgrass Management Strategies

Good Gardening Practices

Good gardening practices are always so important with all facets of gardening; plant and soil health go hand in hand. But maintaining good practices will also help to reduce and manage nutgrass infestations. The following practices I always try to follow:

Nutgrass Flower
  • Maintain a healthy garden or lawn through proper watering, fertilization, and aeration to minimize the conditions favorable to nutgrass. Amongst other things, the appearance of nutgrass can mean that you are overwatering!
  • Use organic mulches to suppress nutgrass growth and promote the health of desirable plants. The presence of a thick layer of mulch will also make the physical removal (nut and rhizomes) of any new nutgrass growth much easier.
  • Don’t overwork your soil. Soil that is overworked (tilled or dug-over) impacts negatively on the health of the soils micro-biome but it can also cause the tubers (nuts) of the nutgrass to come out of their dormancy. These tubers can remain dormant in your soil for many years, and heavily working your soil can ‘wake them up’ and stimulate them to grow.

Physical Control

  • Regularly mow lawns to prevent nutgrass from producing seeds and to weaken its growth. Over time, the weakening of this growth will ultimately lead to a depletion of the food stores in tuber, resulting in a weakening of the plant overall.
  • Hand pulling can be effective for small infestations, but it's crucial to remove the entire plant, including the tubers and rhizomes. If you allow the weed to become too well developed, it will be almost impossible to deal with in this way over larger garden areas.
  • In garden beds, suppress its growth with the addition of layers of cardboard followed by mulches and compost. The mulches should be layers of hay/straw and composts such as mushroom compost. These layers do need to be quite thick (20 to 30 cm) and will enable early identification and removal of weeds that emerge over the following weeks and months.

Herbicide Application

  • There are commercially available selective herbicides that specifically target nutgrass. These can be applied with no danger to other plants in the target zone. But please be aware of the following:
    • They are typically expensive, but you do only need a small amount.
    • If you intend spraying a vegetable garden, there are significant withholding times for produce that you might want to grow. This can have the effect of making your vegetable garden unusable for a period of time.
  • Apply herbicides when nutgrass is actively growing, typically during the warmer months.

Prevention Measures

  • Avoid bringing contaminated soil or plant material into your garden. A problem with this; and yes, it has happened to me, is that it is extremely difficult to know if the soil is contaminated. If it contains dormant nuts, it is almost impossible to know. I therefore recommend bringing new soil onto your property only when it is absolutely necessary.
  • Be vigilant in monitoring and treating new infestations promptly to prevent widespread growth.

Nutgrass FAQs

What is nutgrass, and how does it differ from common grass?

Nutgrass, is a perennial weed belonging to the sedge family. It differs from common grass due to its triangular stem and reproductive structures such as tubers and rhizomes, which contribute to its aggressive and persistent growth.

Why is nutgrass considered a weed, and what problems does it cause?

Nutgrass is considered a weed because of its invasive nature and ability to outcompete desirable plants. It can disrupt the aesthetics of lawns and gardens, competing for essential resources like water, nutrients, and sunlight, leading to an unsightly appearance and potential damage to other vegetation.

How does nutgrass spread, and what makes it difficult to control?

Nutgrass spreads through underground rhizomes, tubers, and sometimes seeds. The presence of tubers allows it to survive adverse conditions, making complete eradication challenging. Even small fragments of rhizomes left in the soil can regenerate into new plants, contributing to the weed's resilience.

Are there different types of nutgrass, and do they require different management approaches?

Yes, there are several species of nutgrass, with yellow and purple nutsedge being the most common. The general principles of managing each of these species are similar.

Can nutgrass be controlled organically, without the use of chemical herbicides?

Yes, organic methods can be employed to control nutgrass. Good gardening practices like proper lawn maintenance, organic mulching, and hand weeding are effective organic approaches.

When is the best time to control nutgrass in lawns and gardens?

Nutgrass is most effectively controlled when actively growing, typically during the warmer months. Applying herbicides or implementing other control methods during this period targets the plant when it is most vulnerable and actively absorbing nutrients.

Is nutgrass harmful to pets or humans?

Nutgrass itself is not typically harmful to pets or humans. However, the methods used to control nutgrass, such as herbicides, may pose risks. It's essential to follow safety guidelines when using any chemical control methods and to keep pets and children away from treated areas until it is safe.

What are some long-term strategies for preventing nutgrass infestations?

Long-term prevention strategies include maintaining a healthy lawn or garden through proper watering, fertilising, and aeration. Avoid introducing contaminated soil or plant material to new areas, as this can introduce nutgrass. Regular monitoring and prompt action against new infestations also contribute to preventing widespread nutgrass growth.

Nutgrass management requires a proactive and integrated approach. Its removal once establish can be hard and prolonged work. But, by combining good gardening practices with physically removing it when it appears, you will be able to control most nutgrass infestations. I would suggest that you only resort to the use of a herbicides as a last resort, but do be mindful of the fact that it may be necessary.

Useful Video

About the author: Steven McLean

I am an educator and passionate gardener and traveler. Throughout my adult life, gardening has been my passion, therapy, drive and source of purpose. Even as a child I had an intrinsic interest in plants and a desire to understand what makes them grow.

I distinctly remember the moment this began - my family was on one of our regular road trips from Hervey Bay; Australia. We were driving past a field of sugar cane. Dad pulled the car over and we cut a couple of sugar cane stems and brought them home for a treat. To be honest, I didn’t really like the taste, but I did want to try and grow it; and that is exactly what I did. It was then that my fascination, interest and passion for gardening and understanding plants began.

Fast forward a few years and I studied biological sciences and began what would be a 36 year career as a Biology educator. From this, I don’t only love gardening, but I also love helping others learn about gardening. I am also always looking for new ways to develop my own gardening knowledge. I like to think I am truly a life-long learner.

Fundamental to my beliefs about education is that learning is often best done as a part of a community - learning from others, and helping others to learn. It is this type of community that I hope iCultivate will be for its members - a community of gardeners, keen to share their gardening knowledge and wanting to learn about new ways to garden - a community built on the love of gardening.

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