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.
Ruellia simplex (exican Petunia), photograph by Dick Culbert; CC.
Ruellia brittoniana (Britton's Wild petunia / Desert petunia / Florida bluebells / Mexican bluebells), picture by Dinesh Valke; CC.
Ruellia tuberosa (Minnieroot / Fever root / Snapdragon root / Sheep potato), Image by Lalithamba; CC.
Ruellia caroliniensis (Carolina Wild Petunia), photograph by Judy Gallagher; CC.
Ruellia makoyana (Monkey plant / Trailing velvet plant), photograph by manuel m. v.; CC.
Ruellia nudiflora (Violet Ruellia / Violet Wild Petunia, Wild Petunia), photograph by Dinesh Valke; CC.
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 10 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 ready transplant outdoors in the middle of spring at about 50 cm (20 inches) apart.
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 cutiings towards the end of spring and summer.
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.