How to Use and Grow Purple Hyacinth Bean Plants

Hyacinth Bean vine

Author: Caroline Léna Becker

Hyacinth Bean Vine ( Also called Purple Hyacinth) is a species of bean in the family Fabacease. It grows throughout the tropical regions of Africa, Indonesia, and India, where it is grown as a food crop since most of the plant is edible.

Even though not widely cultivated, Hyacinth Bean Vine has been a traditional food crop for Africans for many years now.

In America, Hyacinth Bean Vine is more of an ornament plant than a food crop. With shades of purple in the stems, leaves, flowers and showy seed pods, Hyacinth Bean Vine is undeniably eye-catching.

According to Monticello, Hyacinth Bean Vine was sold to Jefferson by his favorite nurseryman, Bernard McMahon, in 1804 and Thomas Jefferson grew it at Monicello over 200 years ago. Because of this, the Hyacinth Bean Vine plant is also known as Jefferson bean.

Features of the Hyacinth Bean Plants

Purple Hyacinth Bean plant produces fragrant purple flowers and striking electric-purple colored seed pods known as Lablab. You can use the flowers and pods for cuttings.

Its bright green, pointed leaves grow in leaflets of three leaves. The flowers resemble sweet peas, without scent. They grow in loose clusters and followed by glossy purple pods that start off looking like snow peas but eventually fill out and plump up.

Its wine-tinted foliage is deep green and textured smoothly. It is a fast-growing vine that will begin to bloom from early summer to early winter. After the bloom period, purple pods will begin to form and can grow up to 3 inches. The beans inside are poisonous so make sure keep them away from children and pets.

Generally, annual plants are very susceptible to frost that can still bloom when frost arrives. Unfortunately, covering this long vine, that may prove impractical.

What is interesting about this vine is its pods are bone on it almost all year round except the winters. Additionally, these vines are good “re-seeders”. If their pods are allowed to open and drop their beans, you will find many new vines next years. You may do not want to disturb your soil until seedlings have begun to grow.

This dark maroon Vine can grow 10′ to 15′ in a single season (Not too bad for an annual).

As a climbing vine, Hyacinth Bean Vine needs some type of support to climb. The support should be sturdy enough to support up to 20 feet of vine growth. A fence, trellis or post works well. It will quickly cover a fence or trellis with large leaves.

Uses in Cooking and a Warning

Hyacinth Bean Wine produces edible leaves, roots, seeds, flower, and pods. Immature, tender pods have a floury, chestnut-like flavor but the flavor is much stronger than the common green bean.

They can be stir-fried or blanched and used in salads or coleslaw like green beans, the purple color disappears with cooking. You can also use the dried beans as shelly beans, but keep in mind the following warning.

Important Note: Uncooked seeds are poisonous as they contain high concentrations of cyanogenic glucosides. They can cause breathing problems, vomiting problems, and convulsions. They need to be boiled for a long time, changing the water twice, to make them edible. Better to leave the cooking to someone experienced with them and save your seed for planting.

Hyacinth Bean Wine is also used as a medicinal herb by Chinese and Indian herbalists.

Uses in Landscaping

Purple Hyacinth Bean plant is a popular choice for the quick cover, although it can frustrate gardeners by refusing to flower until late in the season.

Purple Hyacinth Bean plant is great for creating natural screens or adorning trellises. It creates a fragrant curtain that butterflies, bees, and birds love. Nature lovers will value them for the creatures that they draw to the garden.

Purple Hyacinth Bean’s flowers add a load of color and interest to any garden right from summer through fall.

This climbing vine not only a splash of color but also adds height to your garden. You can use them to add height to a border, by growing them up a trellis or a teepee. You could them ramble through other tall plants, shrubs or trees or use them to cover the arbor or fence.

An array of purple flowers and pods grow amongst lightly aromatic foliage making this an excellent contrast to traditional annuals.

If you’re looking for a vigorous ornamental annual vine that grows at a stellar pace, the Hyacinth Bean Vine may be for you. Because of its lush growth, Hyacinth Bean vine makes an excellent choice for camouflaging eyesores like air conditioning units.

Growing

Site

For the best flowering, pick a sunny site to plant the seeds. Purple Hyacinth Beans thrive in an area with direct sunlight. They can grow in partial shade but along with fewer blooms, you will have the risk of fungal diseases.

Soil

Hyacinth Bean Vine plants prefer a rich, well-draining soils (At a pH of 6 to 6.8). Add some compost to the soil to enrich it with the necessary nutrients needed to fuel their fast, season-long growth.

These plants like a lot of water and nutrients, but they do not like wet soil, their roots will rot in the overly wet soil. So it’s best to keep the soil moist, not wet.

Sowing

You can sometimes buy Hyacinth Bean Vine seedlings in nurseries. The seeds are very hard, it’s best soaked overnight before planting to improve germination.

Plant your seeds after the last frost has passed. Seeds will not germinate well in cold soil and the new plants can be killed by a late frost.

It’s best planted in late spring once weather is warm and settles and nights stay above 50 °F (10°C),

However, direct sown seed is easier and plants will catch up to the seedlings in no time, seeds can also be started indoors several weeks before transplanting outside.

Plant the seeds 1-2 in.deep into the soil with about 6 inches between them. If you worried about poor germination, you can sow the seeds closer and thin them out when they are 2 inches tall.

Dampen the soil to make moist. Adding mulch can help increase the appearance and prevent weeds from growing. Water every day unless the rains occur. Seed should germinate in 10 to 20 days.

When the seedlings are a few inches tall, thin them out to space them 8 to 10 inches apart. This will help the remaining seedlings grow stronger to form a healthy plant without sharing resources.

Fertilizing

Purple Hyacinth Beans need a lot of nutrients. Fertilize often, at least once a month. Add fertilizer when planting and every month during the season. Use a high phosphorous formula just before the first blooming period.

Maintenance

“No plants” is “no maintenance”, but this vine is certainly “low maintenance”. Once established, this vigorous vine can grow well even if it is left unattended. Plants require moderate water twice a week to keep the soil moist, not wet.

When you see the buds appearing, use a high phosphorous formula to promote profuse flowering and seed bearing.

Before flowing starts, you can expect to get a lot of leafy growth. As your plants grow, you may want to support them with a fence or a trellis. Make sure it is sturdy enough to support 10 to 20 feet of vine growth. Once your plants find the support, they will train themselves to grow up it.

It’s a great idea to prune all dead stems and flower deadheads. As a vine, they tend to entangle each other, so prune some inner stems can increase air and light circulation and also promote flowering.

Pests and Disease

One of the best features about Hyacinth Bean Vine is it seldom bothered by insect and disease but will require mild treatment with insecticides, fungicide or repellents as needed.

Sometimes, you may see butterflies’ eggs on the leave and the caterpillars will munch on them for a short period.

Expect more butterflies once they’re done.

When to harvest the Hyacinth Bean seedpods?

Although Hyacinth Bean Vine is used as a food crop in some parts of the world, they are not recommended for eating. Instead, they are used as an ornamental plant in the landscape.

It’s important to know when to harvest the Hyacinth Bean seedpods if you want to grow additional plants.

The best time to pick up your seedpods is just prior to your first frost. Just collect the seedpods and store them in a cool dry place until the next growing season.

Some Facts of Hyacinth Bean Vine

  • Botanical Name: Lablab Purpureus
  • Common Names: Purple Hyacinth Bean, Indian Bean, Egyptian Bean, Tonga Bean, Dolichos Lablab and Tobacco Vine.
  • Category: Annuals; Vines and Climbers
  • Season: Perennial
  • Foliage Color: Blue-Green
  • Foliage: Grown for foliage, Aromatic, Smooth-Textured
  • Bloom Color: Purple & white
  • Bloom Characteristics: Flowers are fragrant and attractive to bees, butterflies, and birds
  • Environment: Full sun
  • USDA Zones: 9 – 11
  • Height: 96 inches
  • Bloom season: Mid Summer, Late Summer/Early Fall or Mid Fall
  • Days to Germination: 10-20
  • Danger: Seed is poisonous if ingested