San José, Costa Rica, since 1956

Clock Vine, a Beautiful Climber

Are you looking for an ornamental to cover that fence bordering your neighbor for a bit more privacy? Here’s just what you’re looking for to do the job.

Clock vine or sky vine (Thunbergia grandiflora), known as Emperatriz Eugenia in Spanish, is a prolific, dense, screening vine for patio walls, trellises and fences, which blooms nearly year-round with beautiful sky-blue flowers. You’ll also find that the flowers make an ideal addition to any flower arrangement.

Originally from the Old World tropics, this plant has adapted well here in the tropical Americas. In fact, you can occasionally find clock vine growing in the wild along forests where it often climbs high into the canopy of trees.

It’s easy to identify clock vine with its opposite, dark-green leaves with pointed tips and toothed edges. The funnel-shaped flowers have five lobed, pastel-blue petals and a yellow throat.

Nurseries around the country offer clock vine and several relatives. T. erecta is a small shrub with blue-purple flowers, though some varieties bear white flowers (T. fragrans). T. alata is a vine with yellow flowers with dark-brown centers and is often called black-eyed Susan.

These hardy plants grow well in the coastal and intermediate regions of Costa Rica and are practically free of pests and diseases, making them ideal eco-ornamentals for the home garden. They grow best in full sun for optimal flowering and need welldrained, average soil. Unfortunately, they will not tolerate salt breezes in the beach areas of the country.

If you are a gardener who enjoys starting your own plants, you’ll find it’s easy to propagate clock vine by seeds, cuttings or layering. Most Ticos are more than willing to regalar (give) seeds or cuttings from their backyard plants.

The seeds or cuttings can be started in the greenhouse in plastic nursery bags filled with prepared potting soil. Keep them well watered until they germinate. Move them into the sun as they grow, and transplant them to permanent sites before they become root-bound.

Remember that you’ll need a trellis, fence or wall for the vines to grow on, except for T. alata, which is a shrub-like ornamental and is often grown in large containers around the home.

Once clock vines are well established, you will need to prune them regularly to keep them in bounds. It’s not uncommon for unattended vines to escape and cover nearby trees or shrubs.

During the dry season, these plants need a light, weekly watering to keep them vibrant and blooming. Apart from this, you’ll find your clock vine ornamental a care-free companion in the home garden.


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