Pennisetum is a popular ornamental grass genus valued for its graceful, arching form and softly fuzzy plume flowers With over 140 species, these grasses display incredible diversity in size, growing anywhere from under 1 foot to over 6 feet tall So just how tall do these impressive plants reach?
In this article, we’ll take a close look at the range of heights among pennisetum varieties. We’ll also provide growing tips to help you achieve maximum height with these vertical standouts.
Pennisetum encompasses a variety of annual and perennial ornamental grasses. The genus includes fountain grasses along with other grass types These plants originate in tropical and subtropical regions of Africa, Asia, Australia, and islands across the Indian and Pacific Oceans
While foliage color, plume shape, and other traits vary, one unifying feature of pennisetum is vertical form. Their upright shape makes them excellent choices as vertical accents in garden beds and borders.
Classifying Pennisetum Grasses by Mature Height
When selecting pennisetum for your landscape, mature size is a key factor. Based on their full-grown heights, common pennisetum varieties can be grouped into three size categories:
- Dwarf – Under 2 feet tall
- Medium – 2 to 4 feet tall
- Tall – Over 4 feet tall
Choosing the right height range for your needs and garden space can help create pleasing design effects. More compact dwarf and medium varieties suit smaller gardens well. Meanwhile, the tallest varieties make dramatic vertical statements perfect for backyard screening.
Petite Dwarf Pennisetum Varieties
For gardeners short on space, compact dwarf pennisetum varieties fit the bill nicely. These diminutive grasses reach just 6 inches to 2 feet when fully mature.
Some top petite varieties include:
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‘Little Bunny’ – Fuzzy, bunny tail-like plumes reach 10-16 inches above fine-textured foliage. The tidy, compact form works beautifully in containers.
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‘Hameln’ – A fountain grass cultivar that stays under 2 feet tall. It offers arching green foliage and fuzzy bottlebrush blooms. ‘Hameln’ also has good cold hardiness.
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‘Little Honey’ – Feathery plumes emerge chartreuse then mature to soft tan. They reach just 1-1.5 feet over fresh green foliage. ‘Little Honey’ adds a pop of bright color.
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‘Moudry’ – Dark green foliage takes on dramatic purple tints. Plants form a tidy 1-2 foot mound topped with deep purple bottlebrush plumes.
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‘Red Riding Hood’ – Although it only reaches about 1 foot tall, this variety offers vivid red foliage for great color impact. Plumes open pinkish then fade to silver.
Mid-Size Pennisetum Varieties
The mid-size pennisetum varieties reach 2 to 4 feet when mature. These grasses provide nice vertical form while remaining scale-appropriate for most gardens. Some excellent options in this size range include:
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‘Karley Rose’ – Rose-purple plumes rise 2-3 feet above lush green foliage. It has a rounded form.
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‘Fireworks’ – Green and white striped leaves complement the pinkish plumes that silver as they age. This variety hits about 3 feet tall.
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‘Rubrum’ – Beloved purple fountain grass with deep burgundy foliage and fuzzy purple blooms. It matures at 2-4 feet tall.
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‘Cassian’ – Dusty rose plumes top sturdy green foliage on plants reaching around 3 feet.
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‘Piglet’ – A tidy grower topping out around 2.5 feet tall. It offers subtle light pink blooms over green leaves.
Towering Tall Pennisetum Varieties
For bold vertical accents, choose one of the many tall pennisetum varieties exceeding 4 feet at maturity. These imposing grasses make excellent screens and backdrops for shorter plants.
Some top tall options include:
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‘Prince’ – Narrow green leaves produce large creamy bottlebrush plumes on plants soaring over 5 feet.
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‘Princess’ – Near 5-foot height is accented by pink-tinged blooms that glow when backlit by the sun. Wide, arching leaves provide great texture.
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Orientale – Quickly reaches 4-5 feet with thick clumps of bushy green foliage and big fuzzy pink plumes.
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Macrophyllum – Huge, wide leaves form substantial clumps. Barely-pink plumes reach up to 6 feet over the foliage.
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Villosum – A fast-spreading grass with delicate, feathery foliage. It grows over 5 feet tall and produces airy, silvery blooms.
Achieving Maximum Pennisetum Height
With proper variety selection and care, pennisetum grasses will thrive and achieve their expected mature heights. Here are some tips for getting the most height out of these impressive plants:
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Choose full sun locations. Pennisetum thrives with at least 6 hours of direct sunlight daily.
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Provide consistent moisture. Water thoroughly when the top few inches of soil become dry. Avoid soggy soils.
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Apply fertilizer in spring to encourage healthy growth. Use a balanced all-purpose fertilizer.
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Stake tall varieties to keep them standing straight and prevent flopping.
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Trim old foliage down to about 6 inches after blooming finishes in fall. This neatens plants for winter.
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Divide mature clumps every 2-3 years to rejuvenate growth. This prevents center die out.
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For pots, select large containers and trim plants smaller as needed. Refresh potting mix yearly.
With so many statuesque options available, gardeners can find a pennisetum grass that achieves just the right mature height for their landscape vision! Proper selection and care will allow these grasses to showcase their impressive vertical form.
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Overview of Pennisetum ‘Fireworks’
‘Fireworks’ is a showy, medium-sized variegated cultivar of purple fountain grass grown as an annual in most areas since it is hardy only in zones 9-10. Although it is usually listed as Pennisetum setaceum, it is actually a sport of red fountain grass, Pennisetum ‘Rubrum’ (which is a hybrid of P. setaceum x P. macrostachys, also named Pennisetum xadvena) that was discovered at Creek Hill Nursery in Leola, Pa. in 2004.
Growing in clumps, this warm season herbaceous grass remains evergreen in mild climates but will die back to the ground in cold conditions. It can grow 24 to 30 inches tall and wide.
The narrow leaves of ‘Fireworks’ are variegated with white and green near the base but have strong red, hot pink, and cream variegation along their length, with a burgundy midvein. The new growth is most vibrant, with the colorful stripes eventually maturing to a rich shade of burgundy. The overall color of the foliage is lighter than red fountain grass (Pennisetum ‘Rubrum’).
Showy reddish-purple, foxtail-like inflorescences appear in mid- to late summer above the foliage, adding color and motion to the landscape. These bottlebrush plumes eventually age to a tan color. It does not set viable seed.
Use ‘Fireworks’ in beds and borders for contrast in color to green plants and for a contrast in texture to mounded or clumping plants; in masses for a stunning display of color; or as small specimen plants. It creates seasonal interest in cottage gardens or rock gardens.
Or plant it alone or in combination with other plants in large containers to provide color on patios and decks. It mixes nicely with annual bedding plants, such as marigolds, petunias, saliva, and zinnia, or can be interplanted between perennials such as coneflowers, sedums, or rudbeckia.
Grow ‘Fireworks’ in full sun for the best coloration. It tolerates a wide variety of soils as long as it has good drainage. It is drought tolerant once established but also can handle moist soil. It is not preferred by deer, has no serious insect or disease problems, and is not affected by juglone.
This tender perennial grass can be propagated by dividing the root ball but as a patented variety (USPP18504), unlicensed propagation is prohibited. Plants can be overwintered if brought indoors in containers in the fall before the first frost. Cut the plants back to about 6 inches, keep in cool, bright conditions, and water through the winter to keep it actively growing until it can move back outside when the danger of frost has passed in spring.
– Susan Mahr, University of Wisconsin – Madison
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FAQ
Does Pennisetum come back every year?
Depending on which type you choose, fountain grass (Pennisetum) can be a deciduous warm-season perennial grass or an annual grass with an elegant mounding habit and cascading fountain-like foliage. Feathery bottlebrush flower spikes provide late-season interest, blooming from summer into fall.
How big does Pennisetum grow?
This cold-hardy grass typically grows in 2-3 foot tall (60-90 cm) rounded mounds of dark green foliage turning golden yellow or beige in fall. However, there are dwarf varieties available that reach only 12 in. (30 cm) and tall ones that can reach 5 ft.
What is the lifespan of Pennisetum?
In conclusion, the average lifespan of Fountain Grass White (Pennisetum Setaceum) is typically 2-4 years, but with proper care and maintenance, it can thrive for up to 5-7 years or more.
Is Pennisetum a warm or cool season grass?
Pennisetum alopecuroides, commonly called fountain grass, is a warm season, clump-forming grass native to grassy hillsides, roadsides, and meadows in East Asia. Mature clumps will reach 2.5-5′ tall with an equal spread.