Ruellia Plant Growing & Care Guide for Gardeners
Article by Dean Ravenscroft, Ph.D. - Updated 24th Oct 2023
In this Gardener's HQ guide, we'll explore cultivating Ruellia plants in your garden, indoor spaces, and other settings.
- Plant Characteristics: Ruellia display beautiful trumpet-shaped flowers, making them a striking addition to any garden. Their evergreen foliage helps add year-round interest.
- Ideal Growing Conditions: Locate in full sun to partial shade in an areas that has a well-draining soil. They're adaptable to moist and dry soils, but regular watering will promote optimal growth.
- General Care: These plants are relatively low-maintenance. Deadheading spent flowers can stimulate further blooms. Prune occasionally to help maintain their shape.
- Tips for New Gardeners: Wld petunias make an excellent choice for beginners due to their resilience. While easy to grow, be mindful that some species can spread rapidly, so regular monitoring and control might be necessary.
Wild petunia, Common Ruellia: Cultivation & Garden Use
Ruellia are hardy and half hardy perennial sub shrubs that reach from 30 to 90 cm (2 to 3 feet) in height.
The main blooming period is from Spring to summer, but many Ruellia plant will also carry sporadic flowers at later times of the year.
Ruellia tweediana by Carl E Lewis.
The flowers of Ruellia are wide ranging in size, but are usually tubular in shape.
One of the more common names for Ruellia is Wild Petunia.
How to Grow Ruellia Wild Petunia
If planning to grow Petunia outdoors from seed then sow in the spring time; lightly cover the wild petunia seed once sown.
Ruellia genus members like to grow in an organic and moist soil, and as they are woodland species should be grown in shaded or partially shaded areas.
If staring off wild petunia indoors then start about ten weeks in advance.
Wild Petunia seeds take from one to two months to germinate at a temperature of 18 to 24 degrees centigrade (64 to 75°F).
Once the seedlinkgs are ready transplant outdoors in the middle of spring at about 50 cm (20 inches) apart.
Caring for Ruellia
It is fairly easy to look after wild Petunia (Ruellia) plants in the garden. They like a moist yet well drained soil, so keep well watered and apply a spring mulch.
If you require more Ruellia plants then Wild Petunia can be propagated by taking cuttings towards the end of spring and summer.
Commonly Grown Ruellia Species
Ruellia simplex
Ruellia simplex (exican Petunia), photograph by Dick Culbert; CC.
Ruellia brittoniana
Ruellia brittoniana (Britton's Wild petunia / Desert petunia / Florida bluebells / Mexican bluebells), picture by Dinesh Valke; CC.
Ruellia tuberosa
Ruellia tuberosa (Minnieroot / Fever root / Snapdragon root / Sheep potato), Image by Lalithamba; CC.
Ruellia caroliniensis
Ruellia caroliniensis (Carolina Wild Petunia), photograph by Judy Gallagher; CC.
Ruellia makoyana
Ruellia makoyana (Monkey plant / Trailing velvet plant), photograph by manuel m. v.; CC.
Ruellia nudiflora
Ruellia nudiflora (Violet Ruellia / Violet Wild Petunia, Wild Petunia), photograph by Dinesh Valke; CC.
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Ruellia Growing and Care Guide
- Common Names: Ruellias, Wild petunia, Common Ruellia, Fever root, Christmas pride, Mexican Petunia, Britton's Wild Petunia, Mexican Bluebell.
- Life Cycle: Hardy perennial. Half-hardy perennial.
- Height: 12 to 48 inches (30—120 cm).
- Native: Americas, Asia.
- Growing Region: 8 to 10 as a hardy perennial; 4 to 9 as a half-hardy perennial.
- Flowers: Spring through to summer.
- Flower Details: Purple, red. Tubular. Showy.
- Foliage: Evergreen. Woody-stems. Linear-lanceolate dark green leaves.
- Sow Outside: Cover seed. Spring.
- Sow Inside: Germination time: one to two months. Temperature: 70 to 75°F (21-24°C). Nine or ten weeks in advance. Transplant outdoors well after the last frost when temperatures do not drop below 65°F (18°C). Space at 18 to 24 inches (45—60 cm).
- Requirements and care: Full sunlight (for best blooms) to full shade, most species perform well in partially shaded hot areas. Fertile, organic soil. Does well in hot humid environments. Very versatile, performs best in wet/boggy soils, though can also grow in average soils with good drainage that are kept moist, and becomes drought tolerant once established. Can spread aggressively through self-seeding and via rhizomes. Propagate: by dividing in the spring in cooler areas or in the autumn in warmer areas. Alternatively take cuttings in spring or summer.
- Family: Acanthaceae
- Closely Related Species: Acanthus.
- Miscellaneous: Classified as invasive in many areas, and is especially a problem in Florida and other South-eastern US states. For this reason consider growing a sterile cultivar such as Ruellia simplex cv. Purple Showers. Attracts brush-footed butterflies (Nymphalinae). Some members of the genus are poisonous, whilst others are used as herbal remedies for urinary problems and as an anthelmintic to destroy parasitic worms.
Common Questions
How many members does the Ruellia genus contain?
The Ruellia plant genus includes approximately 150 species of perennials, shrubs, and subshrubs.
Do Ruellia members make a good garden or landscaping plant?
Yes, Ruellia plants, such as Mexican petunias, are appreciated for their lovely tubular flowers, and some species are used as ground cover or border plants.
Which Ruellia species are most frequently grown by gardeners?
Ruellia simplex, commonly known as Mexican petunia, is frequently grown for its attractive purple flowers and dark green leaves.
Are Ruellia plants fragrant?
Ruellia plants are not generally known for being fragrant, they are more often grown for their ornamental flowers.
What is the perfect location to grow Ruellia?
Ruellia is a versatile plant that can be grown in full sun to part shade, with well-drained soil. It's quite hardy and can tolerate a range of conditions.
Is Ruellia invasive in the USA, if so in which states?
Currently, Ruellia simplex is considered invasive in some southern states of the USA due to its rapid spread and difficult removal.
How do I remove Ruellia plants from my garden?
To remove Ruellia, it's necessary to dig up the entire plant including all root parts, as it can easily regrow from small root fragments.
Summary
Ruellia is a genus of flowering plants, perhaps better known as Wild petunias. Native to the Americas, they offer a diverse range of growth habits, from low-growing groundcovers to tall shrubs.
They grow best in a location with full sun to part shade, in well-drained soil. They can tolerate a wide range of soil conditions, making them a versatile addition to many garden settings. Spring is the optimal planting time.
I hope that you enjoyed this guide on how to grow Ruellia plants. You may also enjoy the following Gardener's HQ growing guides: How to grow Acanthus and Thunbergia plants.
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