Growing and Care Of Purple Needle Grass (Nassella Pulchra)

A native of Western North America and the California state ornamental grass, Nassella pulchra [NAY-sell-uh, PUL-kruh] is found along the West Coast, from Oregon through California, as well as the Cascade Range, Channel Islands, and Sierra Nevada Mountains.

Nassella pulchra bears the full name Nassella pulchra (hitchc.) Barkworth and symbol NAPU4 in botanical plant lists. 

Stipa pulchra (purple_needle_grass) growing in restored coastal prairie habitat
image from oliveoligarchy from California, United States [CC BY 2.0], via Wikimedia Commons

It’s more commonly referred to as purple needlegrass or purple tussockgrass.

The plant is popular for the purple tint to its inflorescence and semi-evergreen nature. 

In summer, the grass turns golden as it prepares for the annual drought conditions in its native region.

This member of the grass family (Poaceae) is often the subject of debate due to its alternate scientific name of Stipa pulchra. 

The term Stipa actually refers to a genus of feather grasses, some of which have a similar appearance to needlegrasses. 

As a result, it also bears the common name purple stipa in some areas.

It is considered a valuable food source by deer and other animals, but the seeds were known to harm the stomachs of cattle, leading ranchers to plant imported grasses. 

The invasive plants left purple needle

grass facing extinction until the onset of recent conservation efforts.

Maps by the Jepson Flora Project show this grass currently inhabits about a third of California. 

The native plant’s reintroduction to formerly inhabited regions continues as more land is reclaimed from invasive species.

Stipa Pulchra Purple Needlegrass Care

Size & Growth

Purple needlegrass is a caespitosa perennial featuring culms ranging from 24″ to 36” inches tall. 

Its leaves tend to be between .031″ and .14” inches wide. 

At the tip of the culm is an open, nodding panicle ranging from 4″ to 8” inches long.

The plant thrives between March and early June, although it will go into hibernation during drought. 

It then hits a second growth period from September or October until December when it once again hibernates until warmer weather.

Some studies claim to have found the roots of a healthy Nassella pulchra extending up to 24’ feet deep, although the exact depth varies based on growth and soil conditions.

Flowering and Fragrance

Purple needlegrass begins to flower in May, its cream inflorescence reaching a length of up to 8” inches. 

The seeds turn purple and are ready to disperse by the end of July. 

Nassella pulchra generally reaches reproductive age at two years, producing as much as 227 pounds per acre.

Light & Temperature

Nassela pulchra seedlings do poorly in shade, while adults can tolerate partial shade. 

This perennial hibernates during periods of cold and can tolerate temperatures as low as 5° degrees Fahrenheit (-15° C). 

This allows it to be planted in USDA hardiness zones 7A and above. 

Watering and Feeding

Purple tussockgrass needs very little watering once established. 

The deep root system allows it to draw moisture most other plants can’t reach.

In extremely dry conditions, the grass merely goes into hibernation, making it difficult to kill from accidental dehydration. 

Soil & Transplanting

Nassella pulchra can survive in a wide range of soil types, and its deep root system allows it to grow in soils containing large clay densities. 

It also thrives in serpentine soil, with a tolerance for sodic soil.

Transplanting is not generally recommended once a plant has established its roots. 

These roots extend several feet beneath the surface and are easily damaged or destroyed in the transplanting process.

Grooming and Maintenance

Nassella pulchra is generally low-maintenance, but it benefits greatly from mowing one to two times per season. 

This simulates grazing and encourages thicker growth. 

Purple needlegrass doesn’t fare well against annual species.

As the plant ages, it may have difficulty growing. 

To stimulate growth, controlled burning is the most common method of rejuvenation. 

Fire, like mowing, encourages fuller growth and won’t harm the root system.

How To Propagate Nassella Pulchra

Purple needlegrass self-propagates during the summer months. 

The flowers are pollinated by air, and the seeds are also wind distributed. 

The needle-like tip of each seed allows it to take root in difficult soil types.

The plant may also be propagated by hand after harvesting its seeds. 

It’s best to keep nearby annual vegetation trimmed so the root system has a better chance to develop.

Purple Stipa Pest or Disease Problems

Nassella pulchra is naturally deer and drought resistant. 

While it isn’t prone to blight, it can cause adverse effects in both humans and pests.

As with most perennial grasses, purple needlegrass can exacerbate or even cause hay fever and asthma.

The seeds may also affect pets, as they can easily become stuck in fur. 

The seed tips are able to cause lacerations in some cases.

As this grass is an important foraging plant, it may attract rodents, such as squirrels, mice, or rabbits.

The seeds have been known to damage the digestive systems of cattle, although this isn’t a common problem.

Suggested Purple Needlegrass Uses 

Needlegrass is a hardy ground cover which can share space with a wide range of plants and trees. 

It works well with almost any shrub. It also compliments wild onions, chives, or other grass-like plants. 

Wildflowers and coastal sage scrub complete the accents for a grasslands-style garden.

Native Americans traditionally prefer this plant to teach basket weaving, and it’s useful in many related crafts.

The deep roots and low moisture needs make purple needlegrass a perfect addition to sand or rock gardens.

Another common strategic use for the plant’s root system is erosion control.

Perennial bunchgrasses such as purple needlegrass benefit grazing livestock. 

Mowing or trimming away any panicles will eliminate the minor risk of seed-related digestive issues.

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