A species of bean in the family Fabaceae, the hyacinth bean vine grows throughout the tropical regions of Africa, India, and Indonesia, where it is more of a food crop than an ornamental plant. Although not widely cultivated, it has been a traditional food crop for Africans for many years now.
This vine can grow anywhere between 4 to 15 feet in height, depending upon the variety. It does not have a wide trailing spread. Its lightly aromatic foliage is blue green in color and textured smoothly. What is interesting about this vine is its purple flowers and striking purple colored seed pods known as lablab, that are borne on it almost all year round (depending upon when it was planted) ) except the winters. A food crop, it is not only edible to humans, but also to the butterflies and hummingbirds, however, for humans the seeds are poisonous as they contain high concentrations of cyanogenic glucosides. They need to be boiled for a long time, to make them edible.
Tips for Growing Hyacinth Bean Vines
An ornamental vine, grown on trellis and screens, this vine has very few requirements for its healthy growth. As it is a fast grower, about 10 - 15 inches every season, one will have to provide it with enough support.
Sowing: This vine can be started with purple hyacinth bean seeds. As the seeds are big in size, they can be directly sown in the intended location. Soak the seeds for a couple of hours in water to speed their seed germination process. One can sow them in Styrofoam glasses too. They don't like their roots to be disturbed, hence avoid transplanting. They are soil hardy, but to grow them fast, use well drained compost rich soil. Sow the seeds 1½ inch deep, and six inches apart. Sow seeds after the last frost date. The seeds will germinate in two weeks time, keep the soil moist until they do.
After Planting Care: These vines just need lots of sunshine and moisture. The soil should be free draining, and not moisture retaining. To ensure longevity, add either organic compost or a slow releasing fertilizer, every month during the growing season. Add a healthy dose of potassium for foliage growth, and when you see the buds appearing, use a phosphorous formula based fertilizer to promote profuse flowering and seed bearing. It is susceptible to frost. To ensure that they survive winters, one can hard prune and mulch around them. One of the best features about it is that there are hardly any insects, pests, or disease problems that inflict them. Prune all dead stems and flower deadheads. Being a vine, it is natural that they will entangle into each other, to avoid that prune some inner stems to increase air and light circulation. Regular light pruning will also promote flowering.
For the next seasons growth, simply collect seeds from the seed pod that has dried on the vine itself. Hyacinth bean vine, with its beautiful flowers and seed pods nestled among the leaves, have quite a number of uses.