Looking up the red fountain grass scientific name can help you identify the plant accurately, choose the right variety, and understand its growing needs. The name most often used is Pennisetum setaceum ‘Rubrum’; it is also sold as purple fountain grass. Before planting, check your local rules: this ornamental grass can be invasive in some warm regions, and some jurisdictions restrict it.
What You’ll Need
- A plant label, nursery listing, or clear photos of the grass, flowers, leaves, and growth habit
- A current regional plant or invasive-species reference, such as a government agriculture or extension website
- If you plan to grow it: a sunny planting site or container with drainage, and well-drained soil
Step-by-Step
- Start with the common name. “Red fountain grass” is a common name, not a precise botanical identification. It is frequently applied to purple fountain grass, a cultivar with reddish-purple foliage and arching flower plumes. Common names can also be used inconsistently by sellers and gardeners, so do not treat the label alone as proof.
- Look for the botanical name on the label. The plant is commonly listed as Pennisetum setaceum ‘Rubrum’. You may also encounter Pennisetum advena ‘Rubrum’ in horticultural references and trade listings, reflecting changes and differing treatments in the plant’s classification. Search using both names when checking a nursery listing or reference.
- Understand the parts of the name. Pennisetum is the genus, and setaceum is the species name in the widely used name. ‘Rubrum’ is the cultivar name, identifying a selected cultivated form; it is not a separate species. Botanical genus and species names are italicized, while cultivar names are set in single quotation marks and are not italicized.
- Compare the plant’s features. Purple fountain grass generally grows in a clump, with narrow, arching leaves in burgundy, bronze, or reddish-purple shades. It produces soft, bristly plumes that rise above the foliage, usually in summer and fall. Color varies with sunlight, climate, plant age, and growing conditions, so foliage color alone cannot confirm an identification.
- Check whether the name fits the particular plant. If your plant has green leaves, different plume shapes, or a very different growth habit, it may be another fountain grass or ornamental grass sold under a similar common name. Compare several characteristics with a trusted botanical garden, herbarium, or local extension service. A photo-based identification can help, but provide close views of leaves, stems, and mature seed heads.
- Verify local planting guidance before buying or planting. Pennisetum setaceum can spread by seed and has become invasive in some regions, especially warm areas. Check local government or university extension guidance for your exact location. If it is prohibited or discouraged, do not plant it, even in a container; seeds may escape through wind, discarded soil, or garden waste.
- If it is suitable where you live, match its basic needs. Choose a site with full sun for the strongest color and flowering, plus soil that drains well. Allow room for a mature clump, and water during establishment and extended dry spells. In climates with freezing winters, treat it as a tender perennial or grow it in a pot that can be protected, depending on local advice.
- Manage flowers and seed responsibly. If local guidance permits cultivation but recommends limiting spread, remove plumes before seeds mature and dispose of them according to local rules. Do not compost seed-bearing heads unless your compost system reliably destroys seeds. Cutting off plumes reduces seed escape but does not make a restricted plant legal or guarantee that it cannot spread.
Common Mistakes
- Assuming every “red fountain grass” is the same plant. Common names vary. Confirm the botanical or cultivar name, and check the plant’s features rather than relying only on its color.
- Calling ‘Rubrum’ a species. It is a cultivar name. The species-level name commonly given is Pennisetum setaceum, though Pennisetum advena ‘Rubrum’ also appears in references.
- Ignoring regional invasiveness. Attractive ornamental grasses may spread beyond gardens. Look up current local restrictions before purchasing, especially in warm climates.
- Planting in shade or waterlogged soil. Insufficient sun can reduce the rich color and flowering, while persistently wet soil can cause poor growth or root problems.
- Assuming a pot prevents spread. Seeds can escape from containers, and plants or soil may be moved or discarded carelessly. Follow local recommendations even when growing in a pot.
Tips
- When searching, try both Pennisetum setaceum ‘Rubrum’ and Pennisetum advena ‘Rubrum’ to find nursery and botanical sources that use different classifications.
- Keep the plant tag or take a photograph of it. The cultivar name is particularly useful when ordering, comparing care advice, or asking an expert for identification.
- For a reliable identification, photograph the whole clump as well as a leaf and a mature plume. Include an object for scale, and note where and when the plant is growing.
- Choose a non-invasive alternative recommended for your area if local authorities advise against fountain grass. A native ornamental grass can provide texture and habitat value without the same risk of escape.
Troubleshooting
- The label uses another scientific name: Check whether it says Pennisetum advena ‘Rubrum’, a name used for the same commonly marketed purple fountain grass. If the species or cultivar differs, ask the seller to confirm the plant’s identity rather than assuming the names are interchangeable.
- Your plant does not look purple: New growth, shade, seasonal changes, and local growing conditions can affect color. Compare the leaves and plumes as well as the color, and request an expert identification if the traits do not match.
- You find conflicting advice about whether it is invasive: Status depends on location and can change. Give priority to current local government, extension, or invasive-species authority guidance over a general gardening article or an old plant label.
- The plant is already established where it is restricted: Stop it from producing seed, avoid moving seed-bearing material, and ask your local invasive-species or environmental agency how to remove and dispose of it. Follow their instructions; do not dump garden waste in natural areas.
- The plant is struggling after planting: Check drainage and sunlight first. Water newly planted grass while it establishes, but let excess water drain. If it declines in a cold climate, consult local advice about winter protection or whether the plant is suited to your area.
Frequently Asked Questions
What is the scientific name of red fountain grass?
The name commonly used for purple or red fountain grass is Pennisetum setaceum ‘Rubrum’. Some references and sellers use Pennisetum advena ‘Rubrum’.
Is ‘Rubrum’ the species name?
No. ‘Rubrum’ is the cultivar name. In Pennisetum setaceum ‘Rubrum’, Pennisetum is the genus and setaceum is the species name.
Is red fountain grass the same as purple fountain grass?
The names are often used for the same cultivar, ‘Rubrum’, but common names are not consistent everywhere. Confirm the botanical name on the label.
Is red fountain grass invasive?
It is invasive in some regions, particularly in parts of the warm world, and may be restricted locally. Check current rules for your location before planting or buying it.
Can I grow purple fountain grass in a container?
Where it is permitted, it can grow in a container with drainage and plenty of sun. A pot does not eliminate the risk of seed escape, so check local guidance and remove plumes before seed matures if advised.
How can I confirm the identity of a plant without a label?
Photograph its clump, leaves, and mature plumes, then compare them with a trusted regional plant reference or ask a local extension office or botanical expert. Do not rely on foliage color alone.