Ornamental grasses

Introduction

An ornamental grass is a type of grass that is considered aesthetically pleasing. Ornamental grasses are cultivated for decorative or aromatic purposes instead of practical purposes. When used in landscaping, they add movement, depth, texture, and create a natural appearance. They may be used indoors, planted in ornamental gardens, used to line sidewalks, or placed around pools, parking lots, or in other urban areas.

In addition to their aesthetic appeal, ornamental grasses can have other benefits. They typically establish deeper, denser root systems than mowed lawn grasses, which can aid in erosion control. Some ornamental grasses are drought resistant and require minimal watering. They can also attract native wildlife by providing food and shelter. 

This page explores common ornamental grasses and their uses.

Decorative ornamental grasses

There are several ornamental grasses that can increase the beauty of a yard and need little maintenance. Ornamental grasses are very versatile and can look modern, formal, or or natural. Listed below are a few of the most common ornamental grasses that are used as for decorative purposes; these plants may add texture and movement to landscaping and provide visual interest: 

• Bunny tails (Lagurus ovatus) have white flower heads that are soft and reminiscent of bunny fur. This grass is used as an ornamental and also dried for flower arrangements. It is native to areas of Europe, Africa, and Asia around the Mediterranean Sea.
• Fountain grasses (selected Cenchrus species, formerly Pennisetum spp.) are known for their feathery flowerheads and fountain-like growth habit. However, some species of fountain grass are invasive, and African feather grass (Cenchrus caudatus or Pennisetum macrourum) is regulated as a noxious weed in the U.S. 
• Feather reed grass (Calamagrostis x acutiflora) is a clump-forming grass. It has feathery plumes that give it its name. This grass is a hybird of two Eurasian species.
• Japanese forest grass (Hakonechloa macra) is popular for its vibrant green foliage and dense, clumping appearance. As its name suggests, this grass is native to Japan.
• Blue fescue (Festuca glauca) has blue-green foliage and a fluffy appearance. It has a clumping growth habit and is often used to line edges. Blue fescue is native to Europe.
• Mexican feather grass (Nassella tenuissima) is native to Mexico, adjacent parts of the southern U.S., and parts of South America. When crushed, it is described to have a light scent.
• Muhly grass (Muhlenbergia capillaris) has a deep green color. The leaves can be up to two feet long. It has airy pink or purple flower plumes, giving it a striking visual display. This grass is native to parts of North America.
• Purple lovegrass (Eragrostis spectabilis) is valued for its purple-pink attractive seed heads. This grass is native to parts of North America.

Aromatic ornamental grasses

Some grasses used as ornamentals contain essential oils to give them a particular fragrance. Such grasses have traditionally been burned, crushed, and sought after for their fragrance. Today, aromatic ornamental grasses may be used to induce a sensation of relaxation, which some people may find decreases stress and anxiety. In urban areas and cities, the fragrances of ornamental grasses can invoke the feeling of being in nature. Compounds from aromatic ornamental grasses are also used in some cosmetic products and perfumes or sold as bottled essential oils that can be used in diffusers or humidifiers. Listed below are ornamental grasses that are also known for their fragrances and aromas:

• Lemongrass (Cymbopogon citratus) is known for its citrusy scent and is used in some cuisines. Most commonly used for its fragrances in southeastern Asian countries such as Thailand and Vietnam, as well as in India.
• Citronella grass (Cymbopogon nardus), which is closely related to lemongrass, has a citrus aroma and is often used as an insect repellent in tropical areas worldwide. It is native to southeast Asia.
• Vanilla grass or sweet vernal grass (Anthoxanthum odoratum or Hierochloe odorata) gives off the scent of sweet vanilla when crushed. This grass is native to Eurasia and Africa. It is considered invasive in parts of the U.S.
• Scented sweet grass (Anthoxanthum nitens) has a vanilla-like scent because it contains coumarin; it is native to large parts of North America and Eurasia. 

Weedy ornamental grasses

Some ornamental grasses can become invasive and outcompete native plants, thereby disrupting local ecosystems. When considering ornamental grasses, especially ornamentals that are not native to your area, it is important to research whether they are considered invasive or potentially invasive. Examples of some ornamental grasses that have been documented as invasive are given below. Note that this list focuses on the U.S.; different species may be considered invasive in different regions of the world.

• Common reed (Phragmites australis): There are native and non-native types of common reed, and the non-native grass is considered invasive in parts of the U.S.
• Crimson fountaingrass (Cenchrus setaceus or Pennisetum setaceum): This grass grows in clumps and has attractive inflorescences. It is native to Africa and western Asia. This grass burns readily and is considered invasive in parts of the U.S.
• Giant reed (Arundo donax): Native to Asia, this impressive grass is considered invasive in parts of the U.S.
• Japanese blood grass (Imperata cylindrica 'Rubra'): This grass is a cultivar of cogongrass that has leaves with striking red tips. Cogongrass is native to Africa and western Eurasia, although it has been widely introduced elsewhere. Cogongrass is considered one of the world's ten worse weeds. This species is regulated under U.S. federal law, and its cultivation and sale have been prohibited in some states.
• Maiden grass or Chinese silvergrass (Miscanthus sinensis): This grass is prized for its graceful, arching form with light plumes on the tips. The white tips represent purity and virginity, hence the name. It comes in a variety of colors. This grass is native to eastern to southeastern Asia and is considered invasive in parts of the eastern U.S. It can invade disturbed areas and burns readily.
• Pampas grass (Cortaderia selloana): This grass forms clumps with spectacular plume-like inflorescences. Native to South America, it has been introduced widely in other parts of the world. This grass is considered invasive on the West Coast of the U.S. and in scattered other states.
• Ravenna grass (Saccharum ravennae or Tripidium ravennae): Native to Africa and Eurasia, this grass is considered invasive in parts of the U.S.
• Reed canarygrass (Phalaris arundinacea): A spreading grass that is native to large parts of the Northern Hemisphere, including North America. Neverthess, this grass is considered a noxious weed in parts of the U.S.

List of selected ornamental grasses

As noted above, some ornamental grasses can be invasive. It is important to research the potential impacts of non-native grasses before planting them to prevent invasive species from spreading in your area.

Warm- or cool-season ornamental grasses

Ornamental grasses either are cool-season grasses or warm-season grasses. Cool-season grasses should be planted in the fall. They begin to grow in winter and flourish in the spring and early summer. Examples include:

• Feather reed grass (Calamagrostis x acutiflora)
• Muhly grass (Muhlenbergia capillaris)
• Blue Fescue (Festuca glauca)
• Mexican feather grass (Nassella tenuissima)

Warm-season grasses should be planted in the spring. They bloom late summer and early fall. Examples include:

• Fountaingrass (Cenchrus spp. or Pennisetum spp.)
• Japanese forest grass (Hakonechloa macra)
• Switchgrass (Panicum virgatum)
• Love grass (Eragrostis spectabilis)

Annual or perennial

Annual grasses have a lifecycle that only lasts one year and they have to be replanted annually. Examples of annual ornamental grasses include:

• Lemongrass (Cymbopogon citratus)
• Fountaingrass (Cenchrus setaceus or Pennisetum setaceum), but see note about weediness above
• Foxtail millet (Setaria italica)

Perennial grasses live for multiple years without needing to be replanted. The benefits of perennial grass are that they usually have deeper root systems, which is better for erosion control. They also may require less maintenance than annuals. These are common perennial grasses:

• Blue fescue (Festuca glauca)
• Switchgrass (Panicum virgatum)
• Purple moor grass (Molinia caerulea)
• Autumn moor grass (Sesleria autumnalis)

Clumping or spreading growth habit

Spreading grasses can expand rapidly and overtake other desirable plants. If the desired ornamental grass is of the spreading variety, it is important to check whether it is an invasive species for your area. 

Clumping grasses are desirable for their compact, neat, and very dense qualities, which prevent weed growth. Clumping grasses include:

• Blue fescue (Festuca glauca)
• Japanese forest grass (Hakonechloa macra)
• Blue oat grass (Helictotrichon sempervirens)

Specific ornamental features

Ornamental grasses with flowering seedheads:

• Fountain grass (Cenchrus spp. or Pennisetum spp.)
• Bunny tails (Lagurus ovatus)

Tall ornamental grasses:

• Giant miscanthus (Miscanthus x giganteus)

Ornamental grasses with vibrant colors:

• Pink foliage: Pink crystals ruby grass (Melinis nerviglumis 'Pink crystals')
• Blue foliage: Blue oat grass (Helictotrichon sempervirens)
• Purple foliage: Purple fountain grass (Cenchrus setaceus or Pennisetum setaceum), but see note about weediness above
• Silver foliage: Silver muhly grass (Muhlenbergia capillaris)

Specific environmental factors

Drought-tolerant ornamental grasses:

• Blue grama grass (Boutelous gracilis)
• Blue avena grass (Helictotrichon sempervirens)
• Purple lovegrass (Eragrostis spectabilis)
• Fountaingrass (Pennisetum spp.)

Shade-tolerant ornamental grasses:

• Tufted hair grass (Deschampsia cespitosa)
• Woodland reed grass (Calamagrostis arundinacea or Calamagrostis brachytricha)

Deer-resistant ornamental grasses:

• Little bluestem (Schizachyrium scoparium)
• Northern sea oats (Chasmanthium latifolium)
• Blue fescue (Festuca glauca)