How to Grow Purple Fountain Grass

purple fountain grass

The Spruce / Autumn Wood

Purple fountain grass is aptly-named for the arcing spikes of purplish flowers that gracefully spray out of its mass of long, slender, burgundy-colored leaves. Native to Africa and Asia, it's technically a tropical ornamental grass, meaning it's not very cold-hardy, but is still well worth growing in cold-winter regions even if you can only enjoy it for two seasons out of the year. It has a fast growth rate and is best planted in spring.

The beauty of purple fountain grass makes it popular as a focal point in a mixed planting, and it is often used in container gardens. You can also mass several of the plants together to create a visually beautiful border or privacy screen. Because the autumn seed heads of this plant are so attractive, purple fountain grass, like maiden grass, is very useful in fall flower gardens. The feathery seed heads (or "plumes") can later be cut for dried flower arrangements.

Botanical Name Pennisetum setaceum 'Rubrum'
Common Name Purple fountain grass, red fountain grass
Plant Type Perennial ornamental grass
Mature Size 3–5 ft. tall, 2–4 ft. wide
Sun Exposure Full sun, partial shade
Soil Type Moist but well-drained
Soil pH Neutral to acidic
Bloom Time Summer, fall
Flower Color Burgundy red
Hardiness Zones 9, 10 (USDA)
Native Area Africa, southern Asia
Toxicity Non-toxic
closeup of purple fountain grass
​The Spruce / Autumn Wood
purple fountain grass and lavender
​The Spruce / David Beaulieu
Purple Fountain Grass - Pennisetum Setaceum 'rubrum'
 

Purple Fountain Grass Care

Like most ornamental grasses, purple fountain grass can be planted nearly any time of year, though you'll get the most successful establishment in spring. It needs a sunny location with well-draining soil. Since mature plants can reach about five feet tall (and nearly as wide), they should be given plenty of room in the garden with at least 3 feet between plants. When planting, be sure to dig a hole both deep and wide enough to accommodate the roots, and water your purple fountain grass thoroughly after planting. Purple fountain grass may need some staking for support, and take care to plant it in an area protected from strong winds.

Light

Purple fountain grass will tolerate some light shade, but it prefers to be planted in full sunlight. Look for an area in your garden where it will receive bright light at least 6 to 8 hours a day.

Soil

Luckily, purple fountain grass isn't too picky about its soil conditions. Loamy soil often provides the best results, but the plant can do well in many types of mixtures, so long as they're well-draining.

Water

While purple fountain grass is considered a drought-tolerant ornamental grass, it should still be watered consistently as it's getting established in your landscape. Water new plants once or twice a week, allowing time for the soil to dry to the touch between each watering. In areas that receive rain occasionally, you will not need to water the grass once it has become established—areas that are particularly dry or hot may need the occasional watering.

Temperature and Humidity

One of the perks of purple fountain grass is just how versatile it is when it comes to temperature conditions. It's cold-weather hardy down to about 20 degrees Fahrenheit, so if your area remains about that temperature, then you can grow the grass as a perennial and cut it back in early spring each year. New growth will initiate as the temperatures begin to climb.

Meanwhile, those in colder zones will have to make do with enjoying purple fountain grass's vivid color and striking, vase-shaped form throughout the late spring, summer, and fall—unless they don't mind going through the trouble of overwintering it indoors. Additionally, the grass has no special humidity needs.

Fertilizer

Fountain grass grows fairly well in poor soil, but fertilizer will boost its growth and provide the additional nutrients it needs when flowering. During that time (typically the summer), feed it monthly with a general-purpose, slow-release fertilizer.

Purple Fountain Grass Varieties

  • Pennisetum setaceum 'Fireworks': Another popular cultivar of the purple fountain grass species, this plant has variegated leaves with burgundy in the middle and hot pink at the edges.
  • P. alopecuroides 'Burgundy Bunny': A cultivar of a relatively cold-hardy species of fountain grass in the Pennisetum genus, this variety stands 16 inches tall. The foliage has hints of red in summer, but the color intensifies to a deep reddish-purple in fall.
  • P. alopecuroides 'Little Bunny': Another cultivar of P. alopecuroides, 'Little Bunny' stands 12 inches tall with a slightly greater spread. This variety lacks the colorful foliage of burgundy bunny but features buff-colored flowers.

Pruning Purple Fountain Grass

The standard way to prune purple fountain grass is to cut it back severely in late winter or early spring before it begins its new growth. This eliminates dead foliage and improves air circulation and sun exposure to stimulate the growth of new leaves. You can also selectively trim dead foliage and perform some light shaping on the plant any time of the year.

To cut back the plant in spring, gather the leaves of each plant, and bind them with a rope or bungee cord. Use pruners or a scythe to cut the leaves straight across, four to six inches up from the base of the plant. Comb through the trimmed leaves by hand to remove any additional dead blades and debris.

Propagating Purple Fountain Grass

Purple fountain grass can be propagated through seed or division. The plants may readily self-seed in the garden, but root division is a faster and more reliable form of propagation.

  • Seeds: This grass produces flowering stems, which are full of feathery seeds. Collect the seeds when they're dry, usually in fall by taking the whole stem and allowing the flower stalk to dry out in a cool place. Surface sow the seeds in good potting soil with just a dusting of sand on top. Water until the container is evenly moist, then place the pot in a plastic bag or cover it with a plastic dome. Once you have seedlings with two sets of true leaves, transplant them to larger pots. Harden them off in spring and install them in prepared containers or beds.
  • Division: Dig up the plant when it is going dormant and cut it into two or more sections with healthy roots and leaves. Use very clean, sharp implements to make your cuts, and discard any rotten or dead plant matter and roots. Replant immediately and keep the soil moist as the division settles into its new home.

Common Pests and Diseases

The good news: Purple fountain grass is pretty resistant to pests and diseases. That being said, there are a few more common issues you should keep an eye out for when planting this ornamental in your landscape. The most common, fungus, is due to trapped moisture or humidity between the dense clumps of grass, so make sure to place your plants several feet apart from one another to increase airflow. Additionally, you may notice the likes of slugs and snails around your grass, but don't stress—while they may occasionally eat the foliage, they're unlikely to cause serious, long-lasting damage.