Purple Fountain Grass Guide: How to Care for Pennisetum Setaceum ‘Rubrum’

Read our guide to Purple Fountain Grass for everything you’ll ever need to know! Tips for planting & caring for Pennisetum Setaceum ‘Rubrum’

Pennisetum setaceum ‘Rubrum’ is a favourite ornamental plant among gardeners, providing long-lasting interest throughout the year. This beauty right here goes by many common names including Purple Fountain grass, Red Fountain grass, or Tender Fountain grass. Member of the Poaceae family, it is native to the tropical regions of Africa and southern Asia.

Purple fountain grasses have won many hearts not only due to their gorgeous appearance but also for their low-demanding nature. These irresistible plants have all it takes to become your next lifetime buddies with little to no effort on your part. They become drought-tolerant once established and can also grow in a wide variety of lighting conditions, soils, and temperatures.

If we have piqued your interest, keep reading our guide and get more familiar with the charming Purple Fountain Grasses!

About Purple Fountain Grass

  • Prized for their natural attractiveness, Purple Fountain grasses are one of the greatly appreciated cultivars that have gained the prestigious Award of Garden Merit from the Royal Horticultural Society.
  • Purple Fountain grasses come with superb feathery seed heads or plumes. In late autumn, many people cut these parts from the mother plants and use them to create lovely dried flower arrangements.
  • In general, these plants are deer-resistant, but they will attract birds once the seeds begin to show up. They can become pretty invasive since birds usually collect their seeds and spread them wherever they feel like it.
  • Purple Fountain grasses are a focal point wherever you plant them. These ornamentals are versatile, providing a showy and dramatic effect in mass or group plantings. They are wonderful additions to borders, courtyards, and even containers.
  • Purple Fountain grasses will look great when planted near other popular species of garden plants. The most common companions are Agastache ‘Blue Fortune’, Crocosmia ‘Lucifer’, Licorice Plant, Mexican Sunflower, Purple Japanese Barberry, Salvia ‘Victoria Blue’, and Tall Verbena.
  • While Purple Fountain grasses are generally considered non-toxic plants, they can cause mild intoxication symptoms to humans and animals if ingested. To be on the safe side, plant these grasses in a place where your kids and pets won’t reach them.
Purple Fountain Grass
Purple Fountain Grass

Purple Fountain Grass Features: An Overview

  • These plants belong to the Pennisetum genus that contains about 80 species of annual or perennial grasses. They share this genus with other spectacular species like P. clandestinum, P. glaucum, P. orientale, P. pedicellatum, or P. purpureum.
  • Purple Fountain grasses are ornamental perennials that can reach from 3 to 5 feet (0.9-1.5 m) in height and 2 to 4 feet (0.6-1.2 m) in width. They grow at a pretty fast pace and have an overall round, mounding growth.
  • Their foliage consists of long, narrow, striking, and arching leaves that emerge directly from the roots. The leaves can appear in several shades of dark purple to burgundy.
  • In general, Purple Fountain grasses bloom from mid-summer until the first sign of frost. During this long period, they exhibit soft, fluffy, burgundy red to purplish flower plumes on long, slender, and arching stems.
  • When Purple Fountain grasses manage to reach over one foot (30 cm) in height, they will start to bear burgundy or purple-tinged seed heads where their flower spikes once were.

Growing Purple Fountain Grass

Even if Purple Fountain grasses can perform well in locations with light shade, they will thrive under full sunlight exposure. Make sure you grow these hypnotic plants in a place where they can receive lots of bright and direct light. In general, they will grow healthy and happy if you expose them to plenty of direct sunlight for at least 6 to 8 hours daily.

Temperature-wise, Purple Fountain grasses come with remarkable versatility. These plants are winter hardy in the USDA zones 9 to 11 and can withstand summer temperatures in the 8 to 12 heat zones. Most gardeners grow their Purple Fountain grasses as perennials in those areas where temperatures can drop to about 20 °F (-6 °C). In regions with cooler weather, we recommend you grow your plants outdoors from late spring through fall, then overwinter them indoors in pots if possible.

Luckily, Purple Fountain grasses are somewhat carefree regarding fungal diseases and pest surprises. Yet, some common intruders like snails or slugs may bother your plants once in a while. While these pests enjoy eating their foliage occasionally, they present no major threat to your plants because they do not usually cause serious, long-lasting damage.

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Planting Purple Fountain Grass

You can plant your Purple Fountain grasses absolutely anytime throughout the year without worrying about their well-being. However, these plants will settle in their new home much easier if you plant them in spring. As a general rule, you will have to provide your buddies with a nice, deep drink right after planting to help them establish.

Since they usually grow and spread like crazy, your plants will need plenty of space to develop properly. Make sure you plant them at over 3 feet (90 cm) apart from each other. Likewise, the planting hole should be both wide and deep enough to better accommodate the roots of your Purple Fountain grasses.

When it comes to their growing medium, these plants are probably among the most easy-going garden companions out there. Purple Fountain grasses will typically do just fine in a wide range of soils, as long as they come along with great drainage. Still, the loamy substrates that are on the neutral to acidic side will often show the best performance with time.

Because Purple Fountain grasses grow pretty well in poor soils, they do not require fertilizing too often. But! During their blooming period, fertilizers will boost the growth of your plants and also ensure the needed nutrients. Feed your grasses with an all-purpose slow-release fertilizer once every month from mid-summer to late autumn.

Purple Fountain grasses have a fast-growing habit, so you will have to prune them regularly to keep their size and shape under control. Before your plants begin their new season of growth, usually in late winter or early spring, cut them back at 4 to 6 inches (10-15 cm) above the soil level. If your plants have an overall messy look, however, you can also remove any dead leaves at any time of the year.

Pennisetum Setaceum ‘Rubrum’
Pennisetum Setaceum ‘Rubrum’

Watering Purple Fountain Grass

In terms of watering, Purple Fountain grasses will need your constant attention only during their first year of growth after planting. Water your new, young plants whenever their growing medium has dried out completely, usually once or twice a week.

Once established, however, Purple Fountain grasses become fairly tolerant of drought for long periods. If you live in a region with hot and dry conditions, you will have to provide your beloved plants with drinks only occasionally. Moreover, in areas with regular rainfalls, you can even forget about watering your plants for good. That’s because, in this type of climate, they will typically get all the moisture that they need from rainwater.

Propagating Purple Fountain Grass

Without a doubt, Purple fountain grasses look at their best in landscape decorations when you plant them in masses. And if you do not have enough specimens around already, do not worry! You can easily obtain more of these stunning ornamentals by propagating them through division or seeds.

Purple fountain grasses may self-seed in the garden without extra effort on your part. However, using division will increase your chances of success and will also take less time to show nice results. In fact, this method will produce more specimens in the blink of an eye!

When your plants are going dormant, usually in winter, dig them out of their growing medium. Then, divide their roots into two or more sections, but make sure each has healthy roots and leaves attached to it. This is a good time to get rid of any unhealthy or dead parts that you can find on your tiny plants. Once you finish with this, you can replant your baby purple fountain grasses in their permanent spots and keep their soil moist until established.

If you want a challenge in your gardening routine, starting your own purple fountain grasses from seed might be exactly what you are looking for. First things first, you have to collect the seeds from your plants when they are dry, typically in autumn. You can do this by cutting some stems, then allow their flower stalks to dry out in a cool room. When the seeds seem dry, you can sow them in potting soil topped with a bit of sand.

Water the seeds until the substrate is damp to the touch, cover the pot with plastic wrap, then place it in a cool, well-lit area. With proper care, the seedlings will develop a healthy root system and 2-3 sets of leaves in a few months. After this period, you can transplant the seedlings into their new, permanent environments.

In Conclusion

If your garden seems to lack a dash of purple in its colour palette, purple fountain grasses are surely the ideal candidates to complete your collection! Besides their obvious fabulous look, what makes these plants a must-have in your plant family is their ability to grow in a wide range of environmental conditions. Also, they are pretty easy to propagate, so you will have them around for a very long time!

Miruna is an experienced content writer with a passion for gardening. She is the proud owner of an outdoor rose garden and an indoor collection of tiny succulents. She bought her first succulent 10 years ago - an adorable Echeveria Setosa. Now she owns more than 100 succulents and cacti of different colors, shapes, and sizes. Miruna is a versatile writer and, as you might have guessed, her favorite topic is gardening. Contact

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