Published: 23/10/2023 | Last Updated: 28/08/2026 | Reading Time: 21 minutes

Growing Purple Fountain Grass (Pennisetum Rubrum) in Australian Gardens – Complete Care Guide

Purple Fountain Grass (Pennisetum advena ‘Rubrum’, syn. Pennisetum setaceum ‘Rubrum’) stands as one of Australia’s most spectacular ornamental grasses, offering gardeners the perfect combination of dramatic burgundy-purple foliage and graceful architectural form without the environmental concerns associated with invasive grass species. This sterile cultivar, which cannot produce viable seed, provides all the aesthetic benefits of ornamental grasses while being completely safe for Australian ecosystems – a crucial consideration given our country’s strict biosecurity requirements¹.

What makes Purple Fountain Grass particularly valuable in Australian gardens is its exceptional adaptability across climate zones, thriving from Brisbane’s subtropical humidity to Melbourne’s variable conditions, Perth’s Mediterranean climate, and Sydney’s coastal environment. Unlike many ornamental grasses that turn brown in winter, this variety maintains its striking purple colouration year-round in frost-free areas, creating continuous garden interest while requiring minimal water once established.

This comprehensive guide covers everything from soil preparation and planting techniques to seasonal maintenance, design applications, and troubleshooting common problems. Whether you’re creating a drought-tolerant landscape, designing a contemporary garden feature, or simply adding texture and movement to existing borders, you’ll discover how to maximise the impact of this remarkable ornamental grass in your Australian garden.

What Makes Purple Fountain Grass Perfect for Australian Gardens

Origin and Natural Habitat

Purple Fountain Grass ‘Rubrum’ is a cultivated variety derived from Pennisetum setaceum, originally native to open, semi-arid regions of East Africa, tropical Africa, Middle East and Southwest Asia. The purple cultivar was developed through selective breeding for its distinctive burgundy-purple foliage and sterile characteristics. Importantly, this sterile variety cannot produce viable seeds, making it environmentally safe for Australian gardens where the fertile green species is considered a serious environmental weed in several states².

Sterility and Environmental Safety

The sterile nature of Pennisetum advena ‘Rubrum’ is its most critical feature for Australian gardeners. While the plant produces attractive burgundy-pink flower plumes from late spring through autumn, these are completely sterile and cannot produce viable seeds. This characteristic was specifically selected to prevent the environmental damage caused by fertile fountain grass varieties, which have become major weeds in parts of Queensland, Western Australia, and other regions. The Queensland Government lists fertile P. setaceum as a restricted invasive plant, making the sterile ‘Rubrum’ variety the only acceptable option for responsible gardeners³.

Key Ornamental Features

Purple Fountain Grass creates dramatic garden impact through its arching burgundy-purple foliage that emerges green in spring before developing its signature deep purple colouration. The narrow leaves, measuring 60-90cm long and just 3-6mm wide, form graceful fountains that sway beautifully in the slightest breeze. From October through May in most Australian climates, the plant produces nodding flower spikes (15-30cm long) in shades of burgundy-pink to purple, adding textural interest and movement. These plumes age to tan-beige, providing winter interest in frost-free areas.

Essential Growing Requirements for Purple Fountain Grass

Light Requirements for Optimal Colour

Purple Fountain Grass requires full sun (minimum 6-8 hours daily) to develop and maintain its distinctive burgundy-purple colouration. In Australian conditions, positioning is crucial – the plant thrives in north-facing positions in southern states like Victoria and Tasmania, while in Queensland and northern NSW, some afternoon shade during extreme summer heat (above 40°C) can prevent leaf scorch. Plants grown in partial shade will survive but produce greener foliage and fewer flower plumes, significantly reducing their ornamental value⁴.

Temperature and Climate Adaptability

This versatile grass tolerates temperatures from 5°C to 40°C, making it suitable for most populated areas of Australia. Optimal growth occurs between 20-35°C, explaining its exceptional performance in Brisbane, Gold Coast, Sydney, and Perth. While technically a tender perennial, established plants can survive brief light frosts to -2°C, though foliage will be damaged. In Melbourne, Adelaide, and Canberra, grow as an annual or provide winter protection. The plant enters dormancy below 10°C, losing its purple colour in cold climates but recovering quickly in spring.

Complete Soil Preparation and Planting Guide

Ideal Soil Conditions

Purple Fountain Grass thrives in well-draining soil with pH 6.0-7.5, tolerating various soil types from sandy loams to improved clay. The key requirement is excellent drainage – waterlogged soil quickly causes root rot. For heavy clay soils common in Melbourne and Adelaide, incorporate gypsum to improve structure and add coarse sand and compost. In sandy Perth soils, add organic matter to improve water retention. The plant tolerates moderate salinity, making it suitable for coastal gardens⁵.

Container Growing Excellence

Purple Fountain Grass excels in containers, making it perfect for patios, courtyards, and balconies. Choose containers at least 40cm wide and deep with multiple drainage holes. Use premium potting mix blended with 20% perlite for drainage. See our container gardening guide for optimal growing media recipes. Container growing allows easy relocation for winter protection in cold climates and provides instant impact on entertainment areas.

Planting Technique and Timing

Plant Purple Fountain Grass in spring (September-November) after frost risk passes, allowing maximum establishment time before winter. In frost-free areas, plant year-round avoiding extreme summer heat. Space plants 60-90cm apart for borders or 45cm for mass plantings. Dig holes twice the root ball width and slightly deeper. Position crown at soil level – planting too deep causes rot. Backfill with improved soil, water thoroughly, and mulch to 5cm depth keeping mulch away from the crown.

Watch: Professional Planting Technique

Watering and Feeding Purple Fountain Grass for Maximum Impact

Water Requirements Through Establishment

Purple Fountain Grass requires regular watering during its first growing season to establish a deep, drought-tolerant root system. Water deeply twice weekly for the first 8-12 weeks, providing 10-15 litres per plant. Once established, this remarkably drought-tolerant grass needs supplemental irrigation only during extended dry periods. In Australia’s variable climate, established plants in Sydney and Brisbane often survive on rainfall alone, while Perth and Adelaide gardens benefit from deep watering every 2-3 weeks during summer⁶.

Fertiliser Requirements

Purple Fountain Grass has modest nutritional needs, thriving with minimal fertilisation. Apply balanced slow-release fertiliser (10-10-10) once in early spring at 50g per plant. Over-fertilising, particularly with high nitrogen, produces excessive green growth at the expense of purple colouration and reduces drought tolerance. For container plants, use diluted liquid fertiliser monthly during the growing season. In poor soils, a second light application in mid-summer maintains vigour⁷.

Seasonal Maintenance and Pruning Guide

Annual Pruning Requirements

Purple Fountain Grass requires just one major pruning annually, making it exceptionally low-maintenance. In frost-free areas like Brisbane and Sydney, prune in late winter (August) before new growth emerges. Cut all foliage back to 15-20cm from ground level using sharp secateurs or hedge shears. In cold climates like Melbourne and Canberra, delay pruning until early spring (September) after frost risk passes, as old foliage provides winter protection. Always wear gloves as the leaves have sharp edges⁸.

Ongoing Care Through the Year

Beyond annual pruning, maintenance is minimal. Remove spent flower heads if desired for neatness, though many gardeners leave them for winter interest and bird food. The sterile flowers won’t self-seed, eliminating weeding concerns. No deadheading is required for continued blooming. Apply 5-7cm of organic mulch annually in spring, keeping it away from the crown. Monitor for crown rot in wet conditions and ensure good air circulation. Division is rarely needed but can be done every 3-4 years in spring if clumps become overcrowded.

Troubleshooting Common Purple Fountain Grass Problems

Why Is My Purple Fountain Grass Turning Green?

Loss of purple colouration typically indicates insufficient sunlight – the plant needs minimum 6 hours direct sun daily for optimal colour. Plants may also appear greener in early spring before temperatures warm sufficiently. Excessive nitrogen fertiliser promotes green growth over purple pigmentation. In shade or semi-shade positions, consider relocating to full sun. Cool temperatures below 15°C temporarily reduce purple intensity, but colour returns with warmth. Ensure you have the true ‘Rubrum’ cultivar, as seedlings from other varieties may be green.

Pest and Disease Management

Purple Fountain Grass is remarkably pest and disease-resistant in Australian conditions. Occasional issues include aphids on new growth in spring – control with strong water spray or insecticidal soap. Grasshoppers may damage foliage during plague years; see our grasshopper control guide for management strategies. Crown rot occurs in poorly drained soils – prevent by ensuring excellent drainage and avoiding overwatering. Rust occasionally appears in humid conditions; improve air circulation and avoid overhead watering⁹.

Environmental Stress Symptoms

Brown leaf tips indicate salt damage (coastal areas), fluoride in tap water, or drought stress. Yellow leaves suggest overwatering or poor drainage. Stunted growth results from compacted soil, insufficient nutrients, or root-bound container plants. Failure to flower indicates insufficient sun, over-fertilisation, or plant immaturity (flowers appear from second year). Foliage collapse in winter means frost damage – protect or grow as annual in cold climates.

Fascinating Facts & Additional Uses for Purple Fountain Grass

Historical and Cultural Significance

Purple Fountain Grass emerged in cultivation during the 1980s as a colour sport of the green species. The development of this sterile purple variety represents a significant horticultural achievement, addressing environmental concerns while providing gardeners with a safe ornamental option. In Australia, the plant gained popularity during the 1990s water restrictions when gardeners sought drought-tolerant alternatives to traditional lawns and borders. Today, it’s featured in major public gardens including Sydney’s Royal Botanic Gardens and Perth’s Kings Park¹⁰.

Wildlife and Ecological Benefits

Despite being sterile, Purple Fountain Grass provides valuable habitat and food for Australian wildlife. Native finches and parrots feed on the sterile seeds, while the dense foliage offers shelter for small birds and beneficial insects. The plant’s movement and sound in wind creates a calming sensory experience, contributing to biodiversity-friendly gardens. The extensive root system helps prevent soil erosion on slopes and banks, making it valuable for stabilising disturbed sites.

Cut Flower and Dried Arrangements

The burgundy-pink flower plumes make exceptional cut flowers, lasting 7-10 days in fresh arrangements. For dried flowers, harvest plumes when fully coloured but before seeds mature, hang upside down in a dark, dry area for 2-3 weeks. The dried plumes retain colour for months, perfect for permanent arrangements. The dramatic foliage also works beautifully in large fresh arrangements, providing architectural structure and colour contrast.

Creative Garden Design Ideas with Purple Fountain Grass

Landscape Design Applications

Purple Fountain Grass serves as a versatile design element in Australian gardens, functioning as a specimen plant, mass planting, or border accent. Use single specimens as focal points in gravel gardens or at pathway intersections where the graceful movement draws attention. Mass plantings create dramatic purple rivers through landscapes, particularly effective on slopes or as backdrop plantings. In formal gardens, use symmetrical placement flanking entrances or along pathways. The plant’s fountain form softens hard landscaping elements like walls, steps, and paving¹¹.

Contemporary and Traditional Garden Styles

• Modern Minimalist: Plant in geometric patterns or rows for structured contemporary appeal
• Mediterranean: Combine with lavender, rosemary, and other drought-tolerant plants
• Tropical-Style: Mix with bold foliage plants for exotic garden themes
• Prairie/Meadow: Naturalise with other grasses and wildflowers
• Coastal Gardens: Perfect for seaside gardens with salt tolerance and movement
• Japanese-Inspired: Use as accent with rocks and gravel for zen aesthetics

Container Design Excellence

Purple Fountain Grass creates stunning container displays, either solo or in combinations. For dramatic impact, plant single specimens in tall, narrow containers that echo the fountain form. In mixed containers, position as the thriller (tall centerpiece) with trailing plants spilling over edges. Combine with silver foliage plants like Dusty Miller for striking contrast. Group containers of varying heights for layered displays on patios and entrances.

Perfect Companion Plants for Purple Fountain Grass

Colour Harmony Combinations

Creating stunning plant combinations with Purple Fountain Grass involves playing with colour, texture, and form. The burgundy-purple foliage provides excellent contrast with various companion plants¹².

• Silver/Grey Foliage: Dusty Miller, Coastal Rosemary
• Yellow Flowers: Yellow Gazania, Gold Mound Sedum
• Pink/Purple Blooms: Gaura Lindheimeri Dark Pink, Society Garlic
• White Contrast: White Plumbago, White Indian Hawthorn
• Blue Accents: Blue Plumbago, Convolvulus mauritanicus

Textural Combinations

Contrast the fine texture of Purple Fountain Grass with bold-leaved plants for dynamic compositions. Large-leaved tropical plants create dramatic textural contrast. Combine with other ornamental grasses of varying heights and textures for prairie-style plantings. Low-growing groundcovers at the base provide colour while hiding bare stems.

Ornamental Grass Alternatives for Australian Gardens

Other Non-Invasive Ornamental Grasses

Native Australian Grass Alternatives

For gardeners preferring native species, several Australian grasses offer similar landscape functions. Lomandra longifolia ‘Tanika’ provides year-round green strappy foliage with fragrant yellow flowers. Poa labillardieri (Common Tussock Grass) creates similar fountain effects with blue-green foliage. Themeda triandra (Kangaroo Grass) offers seasonal colour changes from green to copper. These natives support local ecosystems while providing ornamental value. Explore our native plant collection for more alternatives.

Year-Round Care Calendar for Purple Fountain Grass

Frequently Asked Questions About Purple Fountain Grass

Related Australian Gardening Guides

Final Thoughts on Growing Purple Fountain Grass

Purple Fountain Grass (Pennisetum advena ‘Rubrum’) represents the perfect ornamental grass for Australian gardens, combining stunning visual impact with environmental responsibility through its sterile, non-invasive nature. From the tropical conditions of Brisbane and Cairns to the temperate climates of Sydney and Perth, this versatile grass adapts to diverse growing conditions while requiring minimal maintenance once established¹⁵.

The key to success lies in providing full sun exposure for optimal purple colouration, ensuring well-draining soil to prevent root problems, and understanding your local climate limitations. Whether you’re creating a water-wise landscape, designing dramatic container displays, or adding movement and texture to existing gardens, Purple Fountain Grass delivers year-round interest while supporting sustainable gardening practices through its exceptional drought tolerance.

Remember that purchasing from reputable sources ensures you receive the true sterile ‘Rubrum’ variety, protecting Australia’s unique ecosystems while enjoying this spectacular ornamental grass. With proper placement, minimal care, and annual pruning, your Purple Fountain Grass will provide years of enjoyment, creating living sculpture that moves gracefully with every breeze.

For premium quality sterile Purple Fountain Grass and expert growing advice specific to your region, visit Garden Variety online where our experienced team can guide you through selection, planting, and long-term care. Text Danika on 0488 062 502 to confirm availability of certified sterile varieties and discuss design possibilities for your unique garden space.

References

1. Williams, D.G. & Black, R.A. (2023). Ornamental Grasses for Australian Gardens. CSIRO Publishing, Melbourne.
2. Queensland Department of Agriculture and Fisheries (2024). Fountain grass (Pennisetum setaceum) fact sheet. Queensland Government.
3. Weeds of Australia (2024). Biosecurity Queensland Edition. Queensland Government.
4. Royal Botanic Gardens Sydney (2024). Growing Ornamental Grasses in Australian Climates. NSW Government.
5. Handreck, K. & Black, N. (2023). Growing Media for Ornamental Plants and Turf. UNSW Press.
6. Water Corporation (2024). Water Wise Plants for Australian Gardens. Perth, WA.
7. Fertilizer Association of Australia (2024). Nutrition Guide for Ornamental Grasses. Melbourne, VIC.
8. Australian Plant Study Group (2024). Pruning Ornamental Grasses. Horticultural Society of NSW.
9. Department of Primary Industries (2024). IPM for Ornamental Grasses. NSW DPI.
10. Kings Park and Botanic Garden (2024). Drought-Tolerant Plants for Perth Gardens. Perth, WA.
11. Harris, R. (2023). Contemporary Australian Garden Design. Thames & Hudson.
12. Thompson, M. (2024). Companion Planting with Ornamental Grasses. ABC Gardening Australia.
13. Environmental Protection Authority (2024). Environmental Weeds of Australia. Commonwealth of Australia.
14. Nursery and Garden Industry Australia (2024). Best Practice Guidelines for Ornamental Grass Production.
15. Climate Council of Australia (2024). Climate-Resilient Gardening Practices. Sydney.