Rajin Cajun is known botanically as Ruellia elegans and has been in the marketplace for a little more than a dozen years. For years it was known as elegant ruellia, but most refer to it as false petunia. Ragin Cajun might make you think the plant is native to Louisiana, but indeed it is from South America. I don’t know who named a selection Ragin Cajun, but that certainly helped get it into the marketplace. It is cold hardy from zones 7-10 and should have no issues offering a spring return from temperatures around zero.
As with a lot of perennials, gardeners often make a mistake by judging a plant on first year’s performance. I assure you this plant simply gets better with age. This is the exact reason we tout the “three year” rule when it comes to perennials. Give them until that third year, and you’ll look like a seasoned gardener; for sure, you will be a better horticulturist.
In the first year the Rajin Cajun gets established nicely and for most of the summer sends up shooting star-like stalks topped with brilliant red blossoms. The problem is, there aren’t very many flowers in the first year. By the third year the clump has enlarged considerably, yielding dozens of flower stalks at once.
If the name ruellia scares you because of its aggressive cousins, you will be thrilled at the performance of this one. It has just the right amount of garden vigor. Though called false petunia, Ruellias actually are not related to petunias at all. Petunias are in the family solanaceae, making them related to tomatoes, peppers and eggplants. Ruellia on the other hand is in the acanthus family, along with members such as the shrimp plant and firespike. Ruellias as a group are plants that make everyone look like they have garnered the green thumb.
Ruellias like the Rajin Cajun grow best in full sun, but I have seen some remarkable plantings in shade and they still bloomed profusely. They thrive in moist, well-drained, organic-rich soils but perform well in poorer soils, too.
The dark-green foliage and red flowers offer some unique companion-planting opportunities. One combination that caught my imagination in the past was with Escapade Blue plumbago. The sky blue of the plumbago and the red of the ruellia almost looked patriotic. The combination planting that I liked even better was with a gold variegated duranta. This glossy gold and green duranta, also called pigeon berry, really offered a showy contrast with Rajin Cajun. All I can say is that you would have to see it to believe its beauty. We are growing ours at the base of giant agaves that has become a real attention grabber.