Wallaby Grass

When wallaby grasses are seeding, you know it's nearly Christmas

‘It’s incredible how tough wallaby grasses are, growing very happily in the most inhospitable conditions including clay. On the Bellarine we have 6 types of wallaby grass and they can be identified by the number of rows and length of hairs on the seed.’ Go glorious native grasses!

Sophie Small, Bellarine Landcare Group facilitator, November Facebook post

Common wallaby grass, with fluffy seed heads and fine leaves, discovered in my local nature strip

Like Sophie, I get excited when I discover a surviving remnant patch of native grass. Just this morning, walking along the nature strip on the way to feed my neighbours chooks, growing in an area too dry for exotic grasses, was a beautiful clump of Common Wallaby-grass, Rytidosperma caespitosum. What a delight!

Surviving native plants, like these wallaby grasses, provide quiet reassurance that Australian nature is resilient, surviving in places that are completely altered and crudely managed like town and city nature strips.

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Common Swamp Wallaby Grass happily growing in water

​Wallaby grasses are often the last survivors of local plants because they are tough, long lived and opportunistic. If there is somewhere in a lawn or garden where other plants struggle and a bare patch develops, perhaps affected by the roots of a nearby tree, wallaby grass will 'magically' appear – that’s been my experience.

By the way, Common Wallaby-grass makes a rustic low maintenance lawn because it forms small 10cm wide, fine-leaf clumps, rarely reaching more than 7cm tall. Its long lived fluffy spring flowers/seed heads are also attractive, growing on thin 15cm straw coloured stems.

It can be quite variable, so when you find a remnant patch that you like, use those plants as a source of seed for a lawn or grassland restoration project. As a lawn, Common Wallaby-grass only needs occasional mowing, perhaps just once a year

As proof of their toughness, wallaby grasses stay green all year without watering. They are also frost tolerant, recover quickly after fire and grow happily in a variety of well drained clay or sandy soils.

If it’s too boggy or swampy then look no further than Common Swamp Wallaby-grass, Amphibromus nervosus. Its leafy tufts grow to 30 cm tall, its flowers and seed heads beautifully displaying at about 1m.

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Yeek! the botanical name?

The general botanical name for wallaby grasses is Rytidosperma which is Greek for wrinkled seed - rhytis (wrinkle) & sperma (seed). When I first started growing native plants in the 1980’s, wallaby grasses were generally known as Danthonia which changed in 1993 to Austrodanthonia. In 2011 the genus changed again to its present tongue twister name of Rytidosperma (pronounced;  rit-id-o-sperm-a).

Australia has about 30 species of wallaby grasses that are widespread in the temperate parts of each State. They are often seen on roadsides (and nature strips), in open plains country, grassy woodlands and on lightly forested slopes. They are never alone, because a number of different species of wallaby grass usually grow together. For example, the Greater Melbourne area has 19 species, many of these growing side by side in the same patch of remnant grassland. 

Propagating wallaby grass... 

Wallaby grass seed heads ready to harvest

Four species of wallaby grass, cleaned, stored in the fridge, ready for sowing into tubes, trays or the back paddock

​...from seed

Wallaby grass seed is easy and convenient to collect when it has turned a golden straw colour. Simply cut off the flower heads and store them in a bucket or paper bag for later cleaning. Record when & where the seed was collected and harvest from 20 or more plants to ensure good genetic diversity. If you don’t know its name, take a photo for future reference and to post the photo on iNaturalist (it’s a free app) for identification.

Clean the seed by rubbing the flower heads over a garden sieve until most of it falls through leaving the stem and empty husks behind in the sieve. 

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‘Late spring/early summer is the best time to identify wallaby grass and collect seed as they wave their fluffy straw-coloured heads in the breeze.’
Sophie Small, Bellarine Landcare November Facebook post

Common Wallaby-grass pricked-out into forestry tubes for future sale.

The seed germinates at any time of the year though it needs constant moisture to germinate well. It is a poor competitor at this early stage, so the best results are achieved with a weed free growing environment. The seeds need no pre-treatment for full germination in 7 – 14 days.
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Seeds can be sown directly into tubes (a small pinch of seed per tube), spread on seedling trays for pricking out later, or direct seeded into gardens and paddocks that need to be kept weed free for several months. The recommended sowing rates for big projects is 1 – 2 kg/ha of cleaned seed (with the stems and husks removed like the seeds shown in zip-lock bags above).

Because wallaby grass seed is light, it will blow away in a breeze. So pelletising the seed with clay makes sowing in the field on a large scale more successful and practical.

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Below are 6 species of wallaby grass seed. The three rows of fine hairs visible on the seeds is unique to each species and is used for identification. I have included some of George Stolfo's line drawings for comparison, scanned from an early edition of Flora of Melbourne. The latest (4th) edition is a great reference for detailed descriptions of 19 species of wallaby grass. Hover over each image for the species name and click to enlarge; ​

...by division

​Established clumps of wallaby grass growing in the garden can be divided in winter like many clumping perennials. The best time for this is in the cool weather when the soil is moist and the plants are dormant. It is a slower method though it does provide certainty of form and size for landscapers, which is desirable when creating a uniform soft boarder in a native garden.
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Landscaping
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As mentioned above, Wallaby grasses are a useful landscaping plant to create garden edges, as statement clumps, and for creating a contrast with flowering native herbs and shrubs. Landscapers know that ‘vertical foliage pops’ in garden design and with such a variety of wallaby grasses to choose from, they are well suited to most landscaping projects. The icing on the cake is their unique, fluffy seed tufts that last for months, providing a attractive display when most of the other plants are showing signs of stress in the hot summer sun.

Bristly Wallaby-grass in a mixed bathtub planting of local grassland species at the Bellarine Landcare Nursery

Farming

Wallaby grasses are nutritious for stock, productive and persistent when grazed intermittently or at a low intensity. Researchers have shown that it is possible to maintain native grassland health and diversity by resting grasslands to allow them to recover after grazing or by using a less intensive application of continuous grazing - less animals/ha prevents overgrazing and a large increasing soil nitrogen & phosphorus that kill native grassland plants.
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A moderately grazed, diverse native perennial grassland will cope well with drought and respond quickly to rainfall. Perennial grassland plants like wallaby grasses, provide the maximum production by extracting nutrients and soil moisture from deep in the soil profile.
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Revegetation
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Wallaby grasses need very little maintenance and are particularly useful when used to restore eroded sites or where the soil is poor and shallow. Their toughness makes them ideal for deficient growing conditions where other native grasses and herbs may not survive. They are compatible and supportive of other grassland species and a reliable inclusion in direct seeding mixes or mixed planting with tubestock.

To ensure the survival of wallaby grasses in gardens or grasslands, plant clumps of the same species in groups of 20 - 50 plants. This greatly improves pollination and provides a better resource for wildlife. The number of plants in the clumps will vary with the size of the garden - for example, in large gardens, groups of 50 plants is appropriate and looks very impressive.

A close plant spacing of 15cm - 30cm helps discourage weeds from invading after the wallaby grasses establish and enhances the survival of the new plants.
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The Golden Sun Moth. Photo Julie Cameron

The ecology of wallaby grass
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Having a very nutritious leaf which stays green throughout the year, wallaby grass is important to grazing animals like wallabies and kangaroos.  Above the ground, tufts of wallaby grasses provide excellent habitat for skinks, frogs and small mammals. Insects live under the green tufts and the straw thatch that hugs and protects the soil surface.
 
Wallaby grass provides habitat and food for many butterflies and moths, including the White-banded Grass-dart, the Shouldered Brown and the critically endangered Golden Sun Moth.

The Golden Sun Moth has a 2 year lifecycle, spending most of its life underground as a caterpillar living on wallaby grass roots. After 2 years and only on a warm dry day they emerge as a beautiful moth to mate, lay eggs. Bizarrely the moth has no mouth and is unable to eat. It dies after mating or within 4 days of emerging from the roots of the wallaby grass. 

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Maintenance
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​Wallaby grasses need little/no maintenance for a natural look in the garden or in a restored grassland. They respond well to cool burning in spring/autumn and will green up within a few weeks after rain or hand watering.

If the seed isn't harvested, it spreads naturally, forming beautiful clumps on bare patches, supporting wildlife and adding an element of surprise to an evolving native garden or grassland.