Cymbopogon ambiguus (Native Lemongrass) Growing Guide

What is Native Lemongrass?

Grasses are undoubtedly one of the Earth's most successful plants. Lemongrass in particular has been used by most cultures around the world whether it be medicinal or culinary, but is most synonymous with Asian cuisine. Typically the most commonly used lemongrass is Cymbopogon citratus, due to its stronger lemon scent.

Locally named Aherre-Aherre by aboriginal Arrenre people, Cymbopogon ambiguus is one of 1,300 grasses native to Australia and has bluish-green to grey foliage and fluffy seed heads. A clump-forming grass that has several long raceme flowering stems up to 1m long.

These racemes hold a few flowering heads or clusters that are adorned with spikelets which give the inflorescence this fluffy look. 

What is Native Lemongrass’ Natural Habitat?

Cymbopogon is found growing naturally peppered across Australia excluding the cooler regions. It’s very adaptable to different soils which is why you can find it growing in many native landscapes such as rainforest perimeter, rocky outcrops and savanna. 

It is also found naturalising to the northwest of Australia in Timor, especially along the northern coast. 

Native grassland was once widespread throughout Australia, but agricultural clearance and urban development have almost entirely eradicated it from Southern Australia where less than 1% remains.

Native grasslands are vital to maintaining Australian ecology, reducing these communities of vegetation only has a detrimental chain reaction to our native species of flora and fauna. 

Common Uses for Native Lemongrass

Australian lemongrass was originally used by Aboriginal people medicinally to treat colds and flu. The leaves and roots of the Cymbopogon ambiguus are combined with hot water and steam and then inhaled as a treatment for congestion of chest infections. 

Lemongrass essential oil is antimicrobial so is often found used as an ingredient in soaps, shampoos and moisturisers, additionally giving a citrus scent.

The leaves are an edible bush tucker and are used in cooking either fresh or as a dried herb. Often, as an ingredient, lemongrass is included in marinades as its pungency is a useful way to gain aromatic depth to a dish. 

Lemongrass is also often used in beekeeping where its antimicrobial properties again come in handy. Using just a few drops of lemongrass essential oil around a beehive can help prevent mould and mildew and many beekeepers use it as part of their organic practice.

The antimicrobial and antiviral properties in the oil’s acids can have a positive effect in treating honey bee mites. 

Another interesting use for lemongrass in beekeeping is as a swarm lure. The scent of lemongrass is similar to the smell of scout bees scenting locations for new homes. Cymbopogon ambiguus is highly flammable as is true for most grasses so can often be used as kindling when handled safely. 

How to Grow Native Lemongrass

Native lemongrass is relatively easy to grow as it’s genetically adaptable to whatever you throw at it. It’s useful in ornamental and bush tucker gardens and once established is very drought tolerant. 

Ideal Conditions for Growing Native Lemongrass

Cymbopogon ambiguus will thrive in a sunny position, somewhere that it can reach its potential in height and produce seeds as these are an attractive border softener combined with other prairie-style planting. 

Soil & Drainage

Native lemongrass grows in almost all soil conditions but will do best when provided with good drainage. Nutrition in the form of added pest-free compost or soil improver will give longevity to your plant and help develop a strong root system. 

Light & Temperature

Australian lemongrass wants to be positioned in full sun, consider planting in a pot so it can find the brightest location. It is also frost-hardy, but a thick mulch around the base of the mound will ensure the grass isn’t damaged at all by any harsh weather.

How to Propagate Native Lemongrass 

Cymbopogon ambiguus can be propagated with ease by either seed or by division. Both methods of propagation are commonly practised however seed will take longer but is a lot more cost effective if you have a large space to fill.  

Propagating Native Lemongrass from Seeds

Sow your native lemongrass seed thinly on the surface of some peat-free potting compost. Grass seeds need light to germinate so do not cover them with more compost. Water by misting or laying in a tray of water to soak from underneath.

Put your tray in a warm protected spot and mist occasionally. Germination can be slow but normally takes a few weeks. 

Native lemongrass Propagation from Division 

Division of existing plants is faster and occasionally you can purchase a Cymbopogon ambiguus that can be divided before planting. Lift your native lemongrass using a fork and sink this gently into the centre of the plant.

Using another fork, push into the centre of the plant again and gently pull it apart. 

How to Care for Australian Lemongrass

Cymbopogon ambiguus are very easy to care for, they rarely need much intervention from the gardener, but there are some things you can do to keep your lemongrass looking healthy. 

Feeding in spring with a quality, organic native fertiliser. Lemongrass is a clump-forming perennial that grows in individual ‘tussocks’ rather than swathes that blend together. These individual tussocks can be tailored if need be and also be lifted and divided individually.

Pruning Native Lemongrass

Grasses are low maintenance and don’t need much pruning, but if your native lemongrass starts to look ragged and messy it can be cut back to encourage new growth. Regular harvests of the leaves will also encourage fresh new growth.  

However, if you leave your native lemongrass without tidying it will produce interestingly curled older leaves. As the mature leaves start to dry out they become curled and contrast beautifully to the rest of the plant. I personally love these curly and wavy leaves, they are full of character and elevate the rest of the foliage. 

Repotting Australian Lemongrass

Growing native lemongrass in a pot may occasionally require reporting, if not for size, your grass will eventually need a replenishment of nutrients. You can take advantage of this time to also divide plants which will invigorate new growth along with adding fresh peat-free compost with drainage. Water well to get new plants established. 

Native Lemongrass Bush Tucker Guide

Harvesting can happen at any point you need to use the leaves. It is important to know that there is a specific way to harvest native lemongrass in order to maintain growth. Trace leaves back to where it joins a stem, make your cut here as if you go further into the base of the grass, that particular stem won’t grow back. 

How to Store Native Lemongrass

Native lemongrass can be dried and stored for future use. Depending on your preference of cooking you can dry small pieces or thin slices of leaf. Whole leaves can be dried and then ground into powder or you can freeze it in whatever form. 

Sometimes likened to the flavour of sherbet lemon, lemongrass frozen into ice cubes would serve as a refreshingly zingy drink addition. 

Common Native Lemongrass Pests and Diseases

Cymbopogon ambiguus is not often troubled by many diseases or pests. Slugs and snails seem to dislike lemongrass’ leaves so leave the plant untroubled, and while earwigs are sometimes found around the base of each stalk, they are rare and easy to clean away.

Very wet soil can cause root rot in various forms, but simply digging up, dividing and repotting usually triggers a quick recovery. However, there is one significant recurring ailment to look out for; lemongrass rust.

Lemongrass rust (Puccinia cymbopognis) 

You are more likely to find Cymbopogon citratus affected by this but useful to know the signs. Leaves will have brown rust like patches and pustules on the undersides. It is a fungal disease that can live on lemongrass debris left on the ground and is spread by wind and water splashes.

Dispose of all infected foliage, and irrigate grass from underneath to reduce splashback. Allow space for healthy new growth and ventilation. 

Native Lemongrass Frequently Asked Questions

What is Cymbopogon ambiguus used for?

Cymbopogon ambiguus is a medicinal herb, used as a breathing aid as it helps to dilate airways and relieve chest congestion. It is also a commonly used flavouring ingredient, but its fibrous stems make it a flavouring, rather than a food as it is hard to digest and chew.

Is it ok to drink lemongrass tea every day?

It is safe to drink lemongrass tea every day without toxic effects or negative health implications, but prolonged or excessive use has been known to cause frequent urination and increased appetite.

What does lemongrass do for your garden?

Like citronella, lemongrass is an effective pest deterrent. It won’t grow in some colder parts of Australia, but in most of the country, it is an easy-going outdoor plant that can be used as a companion plant alongside brassicas to prevent aphids, or planted in patio containers to deter mosquitoes. 

What pests hate lemongrass?

Spiders, mosquitoes and houseplied really dislike lemongrass. The fragrance, similar to citronella, is a great deterrent, either in the form of living plants or crushed stems rubbed along your door frames.

If you do a patch test for allergies, it can also be rubbed on yourself as a mosquito repellant.

What are some common problems with lemongrass?

Some of the most common problems with lemongrass are hollowing in the centre of the plant, leaving rings or bare soil, and drying out, especially in containers. Both of these issues can be resolved by digging the plant up, dividing it, and adding new compost.

Is lemongrass safe for dogs?

Lemongrass is toxic to dogs but poisoning is rare because they typically dislike the smell, and tend to find the taste even worse. As well as toxicity, the long fibres can clog up dogs' bowels, potentially causing more serious issues quite rapidly.

Is lemongrass safe for cats?

Lemongrass is a key ingredient in many pet behaviour sprays and drops, used to stop cats scratching sofas. In theory, that means they shouldn’t like the plant itself. However, cats instinctively chew on grasses, including lemongrass to ease gastrointestinal upset.

When they do, it can cause severe gastric blockages and is also toxic. Do not keep lemongrass indoors in homes with cats.

Is lemongrass a herb or a vegetable?

Lemongrass is a herb and is generally used as one. It is very rarely eaten, as the stalks are hard to digest, instead used as a flavouring bouquet to release fragrant lemon-zest notes into sauces.

What is the Indian name for lemongrass?

In Indian cookbooks, lemongrass is often referred to as Malabar or Cochin grass. Both refer to Cymbopogon species. Native Australian lemongrass is interchangeable with other lemongrass species and cultivars.

How many years does lemongrass last?

Lemongrass plants are perennial grasses, and with proper care and attention can be used as productive garden plants for many years. The more often you harvest, the more it will regenerate.

If left in the ground unharvested, lemongrass can become large and incredibly fibrous with limited flavour, so harvest it to increase its lifespan.