With its gorgeous golden throated royal purple blossoms, the scrambling sky flower makes a memorable impression on all who see it. Download a large version (800x600) of this image.
The brilliant blue-purple blossoms of this vine caught my eye as I ran through the garden center trying not to let anything catch my eye. But it did - it was a beauty that had a low, everyday price but was lacking an identification tag. So I bought the mystery plant, stuck it in the dirt way in the back of a bed and then pretty much forgot about it. A few summer rains later I noticed that it had happily established itself. It then proceeded to pump out a bounty of beautiful blue-purple blooms all summer long. First frost put an end to the flowers and the freeze turned the entire plant to mush. But when warm weather returned to my Zone 8 garden so did my blue beauty. Now every year I can depend on it to rebound quickly enough to produce months of blossoms from June to first freeze. After enjoying this plant for more than a decade I at last identified it as Thunbergia battiscombei. Since its flowers resemble those of its cousin the sky flower vine, (T. grandiflora) I took it upon myself to bestow this species with the name scrambling sky flower. Both of these, along with other Thunbergia species are often referred to as clock vines.
So scrambling clock vine (as I guess it could just as well be called) is a herbaceous weak stemmed perennial vine that tends to lean upon other plants for support. When unsupported it will form a symmetrical mound of flopped over stems that is about 4 ft (1.2 m) high by 6 ft (1.8 m) wide. The light green herbaceous stems hold large 5-7 in (12.7-17.8 cm) heart shaped leaves. These are bright green, smooth edged and arranged oppositely along the stems. From the axils (where the leaf attaches to the stem) arise racemes (clusters) of interesting 1 in (2.5 cm) long hairy white flower buds. From these emerge the intense blue-purple trumpet shaped flowers that create such a stunning sight against the handsome foliage. So even though it's not as popular as its cousin the sky flower vine (T. grandiflora) try to find a place in your garden for this attractive, but smaller and less rampant relative.
Scrambling sky flower is a native of tropical Africa.
Not fussy about soil as long as it is well drained. Frequent light feedings of fertilizer reward with frequent flushes of fine flowers.
Light: Sun to part shade. Will grow in total shade but with fewer flowers. Moisture: Provide water when dry, especially when grown in full sun. Will survive short periods of drought if necessary. Hardiness: USDA Zones 10 - 12. This tender tropical is killed back to the ground by frost in Zones 8 and 9 but returns in spring. Treat as annual or overwinter indoors in colder zones. Propagation: Plant seed in spring or take cuttings in summer (they don't form seeds in Florida, probably because the pollinator species are absent). The sprawling stems make natural layers where they touch the ground - clumps form that can be dug and divided.
The scrambling sky flower can be used as a background shrub if allowed to sprawl at the rear of a bed. It's also pretty clambering up a mail box or lamp post. When grown in a hanging basket the gold throated blue-purple trumpets adorn the bright green stems presenting themselves at eye level for maximum visual enjoyment. This small vine combines well with other plants like begonia and impatiens and is happy in any kind of container garden. I like to use this sky flower as a transition plant at the edge of wooded areas among other plants or along fencelines.
Even the fuzzy, greenish-white buds are showy as they rest upon the bright green leaves. When one of the rich blue-purple trumpet flowers bursts forth from a slit in the fuzzy bud you can almost hear it announce itself with a "tah dah!" that makes you want to applaud. Yes, it's that pretty and it is easy to grow, virtually pest free, and almost constantly in bloom! Northern gardeners looking for heat resilient, non-stop bloomers for summertime gardens will want to try this plant (it occassionally pops up for sale at large retail garden center so keep your eye peeled for it!)