Stipa tenacissima (Esparto Grass)

Stipa tenacissima, commonly known as Esparto Grass, is a perennial evergreen grass with long, slender, arching grey-green leaves that form a dense tussock.

During spring and summer, tall flower stalks rise from the dense clump of foliage, adorned with golden-green flower spikelets

It is a very robust grass, hence the species name tenacissima, which means very tenacious. Native to the South and West Mediterranean basin, specifically to Spain, Portugal and North Africa

Stipa tenacissima plant (Esparto Grass, Alfa grass, Needle grass)

Quick Overview

TYPE

Type herbaceous

HEIGHT & WIDTH

Stipa tenacissima height and width

BLOOM TIME

Stipa tenacissima bloom time

SUNLIGHT

full sun

HARDINESS

hardiness (-12ºC / 10º F)

DROUGHT TOLERANCE

ORIGIN

origin mediterranean basin

Esparto Grass Scientific name

  • Botanical name:  Stipa tenacissima (STY-puh ten-uh-SISS-ih-muh)
  • Family: Poaceae (po-AY-see-eye)
  • Common name: Esparto grass, Alfa grass, Needle grass
  • Synonyms: Macrochloa tenacissima
NameMeaning
StipaLatin word meaning stalk or straw.
tenacissimaDerived from latin word “tenax” meaning tenacious. The suffix “issima” indicates “very”. Thus, the complete word means “very tenacious”. 

How to identify Stipa tenacissima

Stipa tenacissima plant (Esparto Grass, Alfa grass, Needle grass)

Plant

Stipa tenacissima is a large perennial grass that forms a dense clump of long, narrow grey-green leaves which remain green all year round.

It slowly grows around the outside, forming a large tussock. Eventually, the centre will die out, which indicates that it is time to divide and replant it.

Numerous stems emerge from the foliage during the late spring and summer months. These stems carry a long, tight panicle densely packed with golden-green spikelets.

Its foliage is 30 cm (1 ft ) high, and the flower stem is around 60 – 80cm (2 – 2.6 ft) long. The width is 40 – 60cm (1.3 – 2 ft).

Observation: This plant is resistant to sea spray.

Stipa tenacissima stem (Esparto Grass, Alfa grass, Needle grass)

Stem

Stipa tenacissima has tall, cylindrical, and hollow flower stems that emerge from the foliage during spring and summer. The stems are smooth, green, and hairless.

Along the stem, 3 to 5 leaves envelop it, and at the top, the tight lance-shaped panicle of pendulous spikelets persists until Winter, adding year-round interest to the garden.

Stipa tenacissima leaf (Esparto Grass, Alfa grass, Needle grass)

Leaf

The leaves are long, very narrow, leathery, and grey-green. They are rolled up at the edges, pointed at the tip, smooth on the underside, and a bit rough on the top. Parallel veins run along the whole length and taper at the tip.

There are also 2 to 5 leaves further up the stem, similar to the ones at the basal leaves. Sometimes, the uppermost leaf partially covers the flower cluster at the top.

The length of the leaf is up to 60 cm ( 2 ft).

In times of drought, the leaves curl up on themselves and take on the appearance of reed leaves.

Stipa tenacissima flower (Esparto Grass, Alfa grass, Needle grass)

Flower

The inflorescence is a compact lance-shaped panicle 25 to 35 cm (10 to 14 inches) long. A whorl of 3 to 4 branches is tightly packed at each node. Each branch has numerous spikelets arranged in a spiral pattern on one side. The spikelets are golden green and have a long awn.

We can easily observe the following parts when the flowers mature and the spikelets open.

The glumes (external bracts surrounding the spikelet) are long and narrow, shaped like a lance. They are translucent with a green or yellowish tint.

The lemma (internal bract protecting the floret) is papery and hairy, shaped like a spindle (wide in the middle and tapers at both ends).

The palea (internal bract protecting the floret) is lance-shaped and has two little teeth at the top. It is translucent with hairs on the back and sticks very close to the floret. When mature, each floret opens up, releasing its pollen and receiving outside pollen. The dangling anther moves with the wind, releasing its pollen, while the feathery stigma easily captures pollen in the air, which then reaches the ovary, developing the seed.


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Stipa tenacissima Habitat

Stipa tenacissima is native to the Mediterranean basin and grows naturally in clearings of scrubland and forests (of pine and holm oak) and near the coast. It forms steppe-like grasslands that can serve as forage but become too tough as they age.

It’s often found on rocky slopes, growing up to an elevation of 1500 meters (4920 feet).

Stipa tenacissima Usage

Ornamental

With its long, slender, arching leaves and elegant golden-green flower spikes rising above the foliage, Esparto grass can add a sense of movement and delicacy to your garden. Its evergreen leaves and long-lasting flower stems provide year-round interest.

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 tall, graceful stems and golden-green flower heads make it an excellent focal point in garden beds and borders. Its striking 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: The fine, feathery panicles of Stipa tenacissma bring texture and movement to garden designs. The light and airy 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 tenacissima is often used in naturalistic or prairie-style plantings to create a sense of movement and wildness. Its native habitat and graceful form make it well-suited to informal garden designs.
  4. Seaside gardens: Its ability to withstand salt spray and strong coastal winds makes it an ideal choice for gardens exposed to maritime climates, where other plants may struggle.

Biodiversity

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

Medicinal

Research has demonstrated Antioxidant and Anticancer potential.

Dried Flower Arrangements

The tall, feathery panicles of Esparto grass add a unique texture and natural elegance to dried floral displays. When harvested at the appropriate stage, the flower spikes retain their shape and colour well when dried. 

Artisanal products

The tough leaves of Stipa tenacissima are used to make ropes, particularly maritime ropes, due to their resistance to water and salt. 

It can also be used for many other crafts, such as baskets, sandals, and mats, and it can even be used to make paper.

The very thin leaves of this grass can be used for delicate and detailed artwork.

Below is a lovely video showing how some craftsmanship with this grass.

Erosion Control

The dense clumps of Stipa tenacissima can help stabilize soil on slopes, embankments, and coastal dunes, making it useful for erosion control in landscaping.

How to care for Stipa tenacissima

Cold exposure

This plant can tolerate frost and cold weather down to  -12ºC (10º 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

Esparto grass needs full sun, it does not like shade.

Soil

Esparto grass thrives in poor, well-drained soils, particularly those with a gritty, rocky texture. 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 prefers alkaline or neutral PH soil but can tolerate mildly acidic soils

Avoid fertilizing the soil if you need the plant to remain robust and better equipped to handle extreme temperatures.

Watering

Esparto grass is extremely drought tolerant and can go for months without water once it is established (about 6 months of drought if the temperature is not too hot). 

It’s essential to water the young plant regularly during its first year after planting. 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 tenacissima do not need to be cut back. 

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

When to plant Stipa tenacissma

The best season to plant is typically spring or autumn, but it depends on your climate. You should 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. In case of 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 tenacissima

Stipa tenacissima 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 

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 Jardin-sec

Article from Carex

Volume 19 from Flora Iberica

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