Stipa, commonly known as Feather Grass, Needle Grass, or Spear Grass. This genus of grasses is known for its graceful, feathery inflorescences and often delicate foliage. Note: The taxonomy of Stipa has been undergoing revisions, and many species formerly classified under Stipa have been reclassified into other genera, particularly Nassella. This addresses Stipa in the broader, traditional sense for this overview, and then clarify the taxonomic changes.

What Makes Stipa So Special?

• Feathery Inflorescences: The defining characteristic of Stipa (in the broad sense) is its beautiful, feathery inflorescences (seed heads). These plumes are often long, silky, and airy, catching the light and swaying gracefully in the breeze. They create a dynamic and ethereal effect in the garden.
• Fine Texture: Many Stipa species have very fine-textured foliage, adding a delicate, almost see-through quality to plantings.
• Movement: The slightest breeze sets the foliage and especially the inflorescences of Stipa in motion, adding a kinetic element to the landscape.
• Drought Tolerance: Many species are highly drought-tolerant once established, making them excellent choices for water-wise gardens.
• Winter Interest: The dried seed heads often persist through the winter, providing structural interest and subtle color during the dormant season.

Description

• Foliage: Typically, fine-textured, linear leaves. Foliage color varies by species, from green to blue-green to silvery-gray.
• Flowers/Seed Heads: The inflorescences are the main attraction. They are typically long, narrow panicles (branched clusters) with numerous spikelets, each bearing a long, prominent awn (a bristle-like appendage). These awns are often twisted, feathery, or silky, giving the seed heads their characteristic appearance.
• Growth Habit: Most Stipa are clump-forming, perennial grasses. Height varies considerably depending on the species, from less than a foot to several feet tall.
• Stems: Slender and arching.

Details

• Bloom Time: Varies by species, but generally spring to summer.
• Hardiness: Varies by species, but many are hardy in USDA zones 5-10.
• Sunlight: Most prefer full sun (at least 6 hours of direct sunlight per day).
• Soil: Prefer well-drained soil. Many are adaptable to a range of soil types, including sandy, rocky, or average garden soil. They generally do not tolerate poorly drained, wet soils.
• Drought Tolerance: Many species are highly drought-tolerant once established.
• Deer Resistance: Generally considered deer-resistant.
• Attracts Wildlife: Provides seeds for birds.
• Salt Tolerance: Some have good salt tolerance.

Native Habitat

Stipa species are found in temperate and subtropical regions around the world, including North and South America, Europe, Asia, and Africa. They are often found in grasslands, prairies, steppes, and open woodlands.

Landscaping Design Tips

• Mass Plantings: Creates a stunning effect when planted in large masses or drifts, where the movement of the foliage and seed heads can be fully appreciated.
• Mixed Borders: Can be incorporated into mixed perennial borders, providing a textural contrast to flowering plants.
• Rock Gardens: Many species are well-suited for rock gardens, where their drought tolerance and fine texture are appreciated.
• Meadow Gardens: Excellent for meadow-style plantings.
• Containers: Some smaller species can be grown in containers.
• Focal Points: The taller species, with their dramatic seed heads, can be used as focal points.
• Backdrops: Can be used as a backdrop for shorter plants.
• Companion Plants:
• Other ornamental grasses.
• Flowering perennials with contrasting flower shapes or foliage textures, such as Echinacea (Coneflower), Rudbeckia (Black-eyed Susan), Salvia, and Sedum (Stonecrop).
• Plants with bold foliage, such as Yucca or Agave.

Planting and Care

• Planting: Plant in spring or fall. Space plants according to their mature size.
• Watering: Water regularly during the first growing season to establish a strong root system. Once established, many species are very drought-tolerant.
• Fertilizing: Generally, do not require heavy fertilization. A light application of compost or a balanced fertilizer in spring can be beneficial.
• Pruning: Cut back to the ground in late winter or early spring before new growth emerges.
• Division: Divide clumps every few years in spring or fall to rejuvenate plants and propagate new ones.
• Pests and Diseases: Generally, pest and disease-free.

Taxonomy

• Kingdom: Plantae
• Phylum: Angiosperms
• Class: Monocots
• Order: Poales
• Family: Poaceae (Grass family)
• Genus: Stipa (and related genera, see below)

The Stipa/Nassella Issue: This is crucial for gardeners. The genus Stipa has been undergoing significant taxonomic revision. Many North American species formerly classified as Stipa have been moved to the genus Nassella. For example, what was once Stipa tenuissima is now Nassella tenuissima (Mexican Feather Grass). However, the common names and much of the horticultural literature still use the Stipa designation. When researching or purchasing plants, be aware of both names.

Morphology

• Roots: Fibrous root system.
• Stems: Slender, often arching.
• Leaves: Linear, often fine-textured.
• Flowers/Seed Heads: Inflorescences are panicles (branched clusters) with numerous spikelets. Each spikelet typically has a long, prominent awn that may be twisted, feathery, or silky.

Popular Varieties (using common names, with updated taxonomy where applicable):

• Nassella tenuissima (formerly Stipa tenuissima) (Mexican Feather Grass, Texas Needle Grass): Extremely fine-textured, with delicate, airy seed heads. Very popular and widely available.
• Stipa gigantea (Giant Feather Grass): A large species (up to 6 feet tall) with golden oat-like seed heads.
• Nassella pulchra (formerly Stipa pulchra) (Purple Needlegrass): Native to California, with purplish awns.
• Stipa capillata (Feather Grass): European species with very fine, hair-like awns.
• **Achnatherum calamagrostis (formerly Stipa calamagrostis) (Spear Grass): Now classified in the genus Achnatherum.

Other Insights for Gardeners

• Self-Seeding: Some species, particularly Nassella tenuissima, can self-seed readily. This can be desirable or undesirable, depending on your garden design. Deadheading can prevent self-seeding.
• Sharp Awns: The awns of some Stipa species can be quite sharp and may be irritating to skin or dangerous to pets.
• Warm-Season Grasses: Most Stipa are warm-season grasses, meaning they actively grow during the warmer months.

In conclusion, Stipa (and its related genera) offer a range of beautiful and graceful grasses with feathery inflorescences that add movement, texture, and elegance to the garden. Their drought tolerance and low-maintenance nature make them valuable additions to a variety of landscapes. The key is to be aware of the taxonomic changes and to research the specific needs of the species or cultivar you choose. The airy, delicate quality of these grasses makes them truly special.