Stipa elegantissima (Feather Speargrass)

Stipa elegantissima more recently classified as Austrostipa elegantissima is commonly known as Feather Speargrass or Elegant Speargrass.

It is an attractive perennial evergreen grass that grows in an upright to decumbent clump with slender green leaves.  

In late spring to early summer, tall slender stems emerge from the foliage, topped with airy, feathery seed heads that start greenish-white and mature to a golden colour creating a stunning shimmering effect.

It is a hardy and drought-tolerant grass, native to South West and South Australia.

Stipa elegantissima plant (Austrostipa elegantissima, Feather Speargrass)


Quick Overview

TYPE

Type herbaceous

HEIGHT & WIDTH

stipa elegantissima height and width

BLOOM TIME

stipa elegantissima bloom time

SUNLIGHT

full sun / semi shade

HARDINESS

hardiness (-15ºC / 5º F)

DROUGHT TOLERANCE

drought tolerance aprox 5 months

ORIGIN

Feather Speargrass Scientific name

  • Botanical name: Stipa elegantissima (STEE-puh el-e-gun-TISS-ih-muh)
  • Family: Poaceae (po-AY-see-eye)
  • Common name: Feather Speargrass, Elegant Speargrass, Desert Speargrass
  • Synonyms: Austrostipa elegantissima (most recent classification)
NameMeaning
StipaLatin word meaning stalk or straw.
elegantissimaDerived from the Latin word “elegans”, meaning elegant. The suffix “issima” indicates “very”. Thus the complete word means “very elegant”. Referring to its attractive inflorescence.

How to identify Stipa elegantissima

Stipa elegantissima plant (Austrostipa elegantissima, Feather Speargrass)

Plant

Stipa elegantissima is a medium-sized perennial evergreen grass that forms a clump of upright to decumbent stems, branching from the base and adorned with slender green leaves.

During late spring and early summer, the flower stalks emerge from the foliage, carrying a pyramid-shaped panicle with widely spread hairy branches that create a feathery effect.

The average height is 1m  (3.3  ft),  up to 2 m (6.6 ft) with flower stalks, and the width is 1 m (3.3 ft).

Stipa elegantissima stem (Austrostipa elegantissima, Feather Speargrass)

Stem

Stipa elegantissima has thin, delicate stems that grow upright to decumbent and branching from the base. They are smooth and hairless with well-defined nodes.

They start out green but mature to a light brown colour.

The lower part has long slender leaves that alternate along the stem, and the upper part carries the flower panicle. 

These slender, flexible stems are strong and support the plant’s graceful form, allowing it to sway gently in the wind.

Stipa elegantissima leaf (Austrostipa elegantissima, Feather Speargrass)

Leaf

The leaves of Stipa elegantissima are narrow and green

The leaf shape is linear and it is flat or enrolled with parallel veins running along its length.

The length is up to 30 cm ( 1 ft) and width is around 1-2 mm (0.04 – 0.08 inches).

The long, slender leaves add to the flowing and graceful look of this grass.

At the base of the leaf blade is a rough sheath (enveloping the stem) and a ligule (an outgrowth at the junction between the leaf and the stem) which is papery and smooth and around 2-7 mm long.

Stipa elegantissima flower (Austrostipa elegantissima, Feather Speargrass)

Flower

The inflorescence is an open pyramidal-shaped panicle 15–25 cm (6 to 10 inches) long. The panicle branches are widely spread and feathery with silky hairs 1.5 to 3mm long.

Each branch has one spikelet, which can be pink, grey, or black and has long white hairs that make it appear white. The spikelet has a long silky awn (which looks like long hair) around 3 – 5 cm ( 1.2 – 2 inches) long.

These long awns, give the flower spike its soft feathery look.

The flowers emerge from late spring to early summer with a silvery green colour and turn to a golden hue in autumn. They last until the end of winter, giving the garden year-round interest.


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Stipa elegantissima Habitat

Stipa elegantissima is native to the Southwest and South of Australia, where it grows in a wide range of habitats. It tolerates full sun and partial shade in open forests and shrublands. It can grow on granite, calcareous soil, clay, loam and deep sands.

It can handle saline conditions as well.

Stipa elegantissima Usage

Ornamental

Feather Speargrass is admired for its graceful and airy presence. Its silver-green hair-like leaves arch from a central clump and are topped with airy, feathery seed heads that sway gently in the breeze, adding movement to the garden. 

The evergreen leaves and long-lasting flower heads add interest all year round.

It is also a very tough plant that requires little attention, making it a great option for a low-maintenance garden.

It can be used in the landscape in the following ways:

  1. Focal point: Its fine texture and graceful airy inflorescences make it an excellent focal point in garden beds and borders. Its soft feathery appearance draws the eye and adds visual interest to the landscape. When illuminated by early morning or late afternoon sunlight, it creates a dramatic effect, especially when it is backlit.
  2. Texture and movement: Stipa elegantissima brings texture and movement to garden designs. The airy, feathery flower spikes offer a gentle contrast with surrounding plants and hard surfaces while also introducing movement when swaying gently in the breeze.
  3. Naturalistic plantings: Stipa elegantissima is often used in naturalistic or prairie-style plantings to create a sense of movement and wildness.
  4. Contemporary gardens: Its airy texture and movement add an interesting contrast and soften the more rigid elements of a contemporary landscape.
  5. Rock Gardens: Incorporate it into rock gardens to soften the hard edges of rocks and boulders. Its airy texture and graceful form complement the rugged beauty of a rock garden. It combines well with Mediterranean plants such as rosemary, lavender and sages.
  6. Container Plantings: Plant it in containers or pots to add texture and visual interest to patio or balcony gardens.
  7. Coastal Gardens: Its tolerance for salt spray and wind makes it suitable for coastal landscapes.

Biodiversity

Stipa elegantissima provides shelter and food for various wildlife species, including birds and insects, making it beneficial for promoting biodiversity in your garden.

How to care for Stipa elegantissima

Cold exposure

This plant can tolerate frost and cold weather down to  -15ºC (5º F). But only if the soil is well drained. Cold, soggy soil can be fatal to it. 

While the plant is not yet established, you may want to add a thick layer of mulch around the plant’s base to protect the roots from cold temperatures. It´s preferable to use gravel mulch because organic mulch will stay humid and can cause the plant to rot.

Sun exposure

Feather Speargrass thrives best in full sun but it can also tolerate partial shade.

Soil

Feather Speargrass thrives in poor, well-drained soils, and even in sand. It’s best to avoid planting it in damp locations, as it is not tolerant of soggy soil, which can increase the risk of root rot.

If your area tends to become waterlogged, you may need to keep the entire root ball above ground level and fill in with a raised mound of sandy soil, sloping gradually away from the plant’s base.

It can tolerate most types of soil PH, from mildly acidic to neutral to mildly alkaline.

Avoid fertilizing the soil to prevent it from flopping over and to ensure that it remains robust and better equipped to handle extreme temperatures and drought.

Watering

Feather Speargrass is very drought tolerant and can go for months without water once it is established (about 5 months of drought if the temperature is not too hot). 

During its first year after planting, it’s essential to water the young plant regularly. Depending on the soil and the temperatures, you may need to water it once a week, every two weeks or every three weeks.

When you water the plant, make sure to give it plenty of water, allowing the soil to get a good soak. This way, the water can sink deep into the soil keeping it moist for longer periods.

To preserve the soil´s moisture, you should add mulch around the root area of the plant. The mulch should preferably be gravel because organic mulch can lead to leaf rot.

Pruning

Evergreen grasses such as Stipa elegantissima do not need to be cut back. 

Instead, you should remove the dried flower heads by the end of winter, which can be pulled off easily. 

After that, comb through the leaves with your fingers to remove the old leaves. This is important because if you leave the old leaves, the plant will be stunted because the new leaves cannot easily grow through them. So, try to clean out as much of the dead material as possible.

There are two ways to remove the old leaves:

  • With your hands – Gently remove the dead leaves, leaving the crown with only the fresh green leaves. Wear gloves for this task because the sharp grass blades can cut your fingers. 
  • With a rake – Alternatively, you can also rake it, which is a faster way of doing this. However, it may damage the new leaves, and you will not get such a nice result. It all depends on how much time you have to do this task. 

However, if the plant begins to flop and look untidy, prune it back hard to about 15cm (0.5 ft) tall by late winter to early spring before the new growth starts. This will encourage vigorous new growth and maintain its neat appearance.

When to plant Stipa elegantissima

The best season to plant is usually in the spring or autumn, but it will depend on your climate. Avoid planting during periods of extreme temperatures.

If you have mild weather where you live, it’s best to plant in the autumn to give it time to develop the roots during the cooler months before the arrival of the hot summer. If you have very cold winters, it’s better to wait until spring when the risk of frost has passed and the soil is warmer. That way, the plant can have a better chance to grow well and be healthy.

How to propagate Stipa elegantissima

Stipa elegantissima can be propagated by seed or by division. 

Division: Mid-Spring to early summer

  1. Dig up the mother plant clump.
  2. Shake off the excess soil to make it easier to divide.
  3. Divide the clump into good-sized sections. Depending on the size of the clump, use a sharp knife, a spade, or even a saw.
  4. Replant the divisions into the garden 

Note: This grass needs frequent division, perhaps every three years, to prevent root congestion and loss of vigour.

Seed: Early spring to early summer

  1. Sow the seeds in a well-draining medium. Lightly press the seeds into the soil, just covering them with a thin layer, as the seeds need light to germinate.
  2. Maintain consistent moisture but not soggy (cover with a plastic lid or bag) and provide indirect light. 
  3. For best germination, maintain a temperature around 15 to 18ºC (60 to 65ºF). Germination should take 2 to 4 weeks, but it can also be erratic and take several months.
  4. Water from the base of the container (don´t water overhead)
  5. Once the seedlings have grown a few sets of true leaves, transplant them into individual containers and grow in cold frame during the first winter, or harden them to outdoor conditions and then plant into their permanent positions after the last expected frosts. 

Sources of information used for this article

Sources

Article from Kew

Article from AusGrass

Article from VicFlora

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