Growing Purple Fountain Grass: How To Take Care of Pennisetum Setaceum ‘Rubrum’

Purple Fountain Grass
Purple Fountain Grass

The name given to purple fountain grass is entirely appropriate given its arcing spikes and purplish flowers. It’s a native cultivar from Asia and Africa and technically classified as a tropical ornamental grass. This means that it’s not seen as being cold-hardy. However, you can still grow this grass in cold-winter regions, but it isn’t expected to last for more than two seasons.

Another characteristic about this purple fountain grass plant is that it’s known to have a fast growth rate is reaches its optimal growth when being planted in the springtime. Like any other plant in your garden, there are specific ways that you can care for this grass to ensure that it grows to its most significant potential. For this reason, we have created this guide that outlines the steps you should follow when planting, growing, and caring for purple fountain grass.

About Purple Fountain Grass (Pennisetum Setaceum ‘Rubrum’)

One of the most fantastic features about this purple grass is that it forms an attractive focal point in any mixed planting, which is like other ornamental grasses. In addition to this, it’s also often used in container gardens. When planting this organism, you have the opportunity to mix several of these plants to gather to present a stunning privacy screen or border.

Much like maiden grass, purple fountain grass includes attractive autumn seed heads, which are exceptionally useful in fall flower gardens. Not to mention, the feathery seed heads, as known as plumes, can be cut later in the season for dried flower arrangements.

Caring for Purple Fountain Grass (Pennisetum Setaceum ‘Rubrum’)

Purple fountain is like most ornamental grasses as it can be planted almost all-year-round. However, you do hold the opportunity to gain the most successful establishment in the springtime. One of the essential aspects you need to consider when caring for a purple fountain plant is to ensure that it’s placed in a sunny location that features well-draining soil and has exposure full of sunlight.

In addition to this, purple fountain also has the potential to reach five feet tall as a mature plant, as well as five feet wide. For this reason, you should provide ample space in the garden with a minimum of three feet of space between these plants. Moreover, when planting this purple fountain grass, you should also dig a broad and deep hole into accommodating the plant’s roots after you have initially planted the purple fountain grass. It would help if you also didn’t forget to thoroughly water your purple fountain plant after planting it. Another crucial element is that the plant might need staking for support. Included in this, you should also plant this grass in a protected area away from strong winds.


The purple fountain plant is equipped to tolerate some light shade. However, this purple fountain grass does thrive when planted in full sunlight. For this reason, you should look at cultivating/ growing the purple fountain grass in an area that allows it to receive six to eight hours of light each day.


One excellent feature about purple fountain grass is that it isn’t too picky about what type of soil conditions it’s planted in. With that being said, our experience has shown that loamy soil generally offers the best results. However, the purple fountain grass plant can grow well under various soil mixtures, as long as this soil is well-draining. It’s crucial that this ornamental grass is placed in the ground that’s well-drained because of its drought-tolerant features.


For the most part, purple fountain grass is known to be drought-tolerant. With that being said, you should still make an effort to water this plant consistently as it’s starting to take shape in your garden. You should water these new plants between one to two times a week. When watering your plants, you should ensure that the soil is dry to the touch in-between watering. If you have planted your purple fountain grass plant in an area that receives rain, you won’t need to go back and water the grass after this ornamental grass has become established. On the other hand, places, where it might be hot or dry, might require you to occasionally water the plant.

Humidity and Temperature

A significant perk of using purple fountain grass in your garden is that it’s incredibly versatile when it comes to the temperature it’s planted in. The plant is known to be cold-weather hardy, as long as it’s placed in more than 20 degrees Fahrenheit weather. If you plan to plant your purple fountain grass under these conditions, you can easily grow it as a perennial and then cut it back during the early spring of every year. New growth is known to initiate when the temperatures start to rise due to more sun exposure. 

With that being said, the colder zones provide the opportunity to enjoy purple fountain grass in a vase with other accompaniments. This is if you wish to have tall purple fountain grass in late spring, summer, and fall. This is unless you wish to plant your purple fountain grass indoors. When growing purple fountain grass, you also have the luxury of these plants not having any humidity requirements. 


It’s widely known that purple fountain grass plants grow fairly easily in poor soil conditions. However, fertilizer can indeed be used to boost seed growth while providing additional nutrients that these plants need when flowering in the early springtime. During early spring or summer, you can feed your purple fountain plants monthly with a slow-releasing and general-purpose fertilizer. This also helps enhance the new growth of newer plants, as well as helping mature plants flourish in size during the early spring, summer, and late winter months. With that being said, you might want to cut back on the fertilizer uses if you notice that your purple fountain grass is outgrowing the area it’s placed in.

What Varieties of Fountain Grass do You Get?

There are more three main varieties of fountain grass that you can get. These are:

Pennisetum setaceum ‘Fireworks’ (Red Fountain Grass)

This Pennisetum setaceum is a popular cultivar that’s related to the purple fountain grass species. It has variegated leaves that feature a Burgundy color in the middle and hot pink at the edges of this leaf. The burgundy color is very pleasing to the eye and needs full sun to succeed when it comes to growing.

Pennisetum alopecuroides ‘Burgundy Bunny’

The Burgundy Bunny is a cultivar of fountain grass species that are known for being relatively cold-hardy. This variety is known to stand up to 16 inches tall. In addition to this, the foliage features hints of red when grown in the summer, and this color is known to intensify to a deep red-purple color when placed in fall temperatures.

Pennisetum alopecuroides ‘Little Bunny’

The Little Bunny is another cultivar and stands up to 12 feet tall and features a slightly larger spread. The difference between this variety is that it lacks the full and colorful foliage when it comes to the flower color of the Burgundy Bunny leaves. Nonetheless, this variety does include flowers that are buff-colored. This plant is hardy in USDA zone 5 – 9.

How to Prune Purple Fountain Grass

The most common way of pruning purple fountain grass is to cut it back severely in the early spring or late winter months before it starts its new growth. When you cut it back, you eliminate any dead foliage while improving the air circulation and sun exposure to this purple fountain grass. In addition to this, you also stimulate the growth of new leaves when you cut it back. 

You also have the ability to cut dead foliage while performing light shaping on an annual basis. When cutting this in spring, it’s recommended to gather the leaves of each plant and bind these together with a bungee cord or rope. You should also use a scythe or pruners to cut straight across this organism. This should be done between four and six inches up from the plant’s base. After this, you should comb through the leaves that have been trimmed by hand to remove any additional debris and dead blades.

Common Diseases and Pests Associated with Purple Fountain Grass

In order to properly care for your purple fountain grass, you need to have the right information pertaining to the common diseases and pests associated with this cultivar. The great news is that purple fountain grass is known to be quite resistant to diseases and pests. However, there are some common issues that you should be informed about. 



Purple Fountain Grass (Pennisetum setaceum ‘Rubrum’) is a stunning ornamental grass known for its vibrant purple foliage and graceful fountain-like growth habit. It is typically grown as a perennial in USDA hardiness zones 9 to 11, thriving in warm climates with mild winters. In these regions, it adds a dramatic and colorful element to gardens, landscapes, and container plantings. However, in colder zones (USDA zones 8 and below), purple fountain grass is often treated as an annual or tender perennial due to its sensitivity to freezing temperatures. With its striking appearance and versatility, Purple Fountain Grass brings an enchanting and ornamental presence to outdoor spaces, creating a captivating focal point or adding texture and movement to garden designs.

Rachel Lean
Rachel Lean

Adventurer, loving nature and plants, particularly Pampas Grass. Happy to share with other people the knowledge that I accumulated on the journey of my life.