Plant portrait: Thunbergia 'Fairy Moon'
When it comes to Thunbergia, gardeners are probably most familiar with Thunbergia alata, the black-eyed susan vine. This annual vine (perennial in climates with little to no frost) is full of small orange or yellow flowers for much of the summer and can reach 6 to 8 feet in a single season from seed. There’s even a dark orange and yellow version. Most of the time T. alata is grown on a trellis or other support outdoors, but can be adapted to indoor culture if there’s adequate space or you’re diligent about pruning it to keep the vine in bounds.
Tropical plant enthusiasts enjoy a wider selection of plants from the genus. If you have a lot of room indoors or greenhouse space, there are stunning perennial vining Thunbergias, the most commonly grown being Thunbergia grandiflora a.k.a. Bengal trumpet or clock vine, whose flowers colors include shades of sky blue to deep blue-purple and white. In Hawaii and other very warm climates, this vine is vigorous to the point of being considered invasive, a problem northern growers won’t have to be concerned with.
One of the most striking greenhouse-grown vining plants I’ve even seen is Thunbergia mysorensis. This one produces two to three foot long pendulous chains of yellow and brick-red flowers.
More practical from an indoor gardening perspective is Thunbergia erecta, also known as king’s mantle, which has a shrubby habit. While plants grow quite large, they can be maintained at a convenient size through pruning (hereabouts we can only dream of growiing it as a six-foot-tall hedge). Flowers come in shades of blue and purple, as well as a pale purple with white edges in the cultivar “Fairy Moon.”
“Fairy Moon” is touted by Logee’s in Danielson, CT where I found my plant as blooming from spring to fall, so I’ve been surprised and pleased to find it in flower almost continuously from fall through early spring under lights. It’s never covered in bloom, but usually has one to several 2-3 inches flowers open. They are said to be lightly fragrant, but I haven’t noticed much scent. My plant has grown slowly and is about 20 inches tall with similar spread. It doesn’t get a huge amount of light, being placed about six inches under a two-tube fluorescent shoplight. It gets the same soil as most of my other plants, Pro-Mix and is fertilized when I think about it, typically with diluted Miracle-Gro or a low-nitrogen bloom formula.
With warm, settled weather due to arrive within a month and a half, it’ll be interesting to see how “Fairy Moon” performs outdoors. If the results are inspiring and I succeed in propagating it by cuttings or seed, it could be a valuable addition to seasonal bedding in the Victor/Victorian garden.