How to Grow and Care Purple Hyacinth Bean Vine

Purple hyacinth bean vines have long graced gardens around the world with their lush foliage, profusion of purple flowers, and bright purple seeds. These hardy flowering vines grow in Africa, climbing any available support that can be tied around them. In addition to their beauty, the ease of care for hyacinth beans, their ability to add nitrogen to the soil, and their edible leaves and buds make these plants worthy of a spot in your garden.

Where to Grow Hyacinth Bean Vine?

Purple hyacinth bean vine can grow quite large. Choose a spot in your garden where these plants can grow without shading other plants or needing to be pruned all the time. Some varieties can reach heights of nearly 20 feet, so it’s important to have plenty of room to attach trellises, fences, or other structures. The ideal location will also provide good air circulation for the plants and will be away from heat sinks such as hot walls or fences in hot climates.

How and When to Grow Hyacinth Bean Vine

Hyacinth bean vine prefer cool weather, but unlike many other beans and peas, they will not tolerate temperatures that drop below freezing. Start seeds indoors 2-3 weeks before the last expected spring frost, then transplant them into the garden after the danger of frost has passed.

Hyacinth Bean Vine Care Tips

Light

Like most fruits and vegetables, hyacinth beans require full sun to produce optimal flowers and seeds. Although they can tolerate some shade, they will produce very little in shady conditions.

Soil and Water

Hyacinth beans vine grow quite large, and because of their size, they require rich soil and plenty of moisture throughout the growing season. Well-drained loamy soil with plenty of organic matter is ideal, although hyacinth beans can survive in many types of soil, provided moisture is present.

Temperature and Humidity

Like many beans and peas, hyacinth beans prefer cool to warm temperatures and low to high humidity. However, excessive heat and low humidity can inhibit growth. In areas with high humidity, provide good air circulation around the vines to reduce disease.

Fertilizer

As part of the bean family (Fabaceae), hyacinth beans produce their own nitrogen with the help of bacteria in the small nodules in their roots. However, due to their rapid growth and large size, your plants will benefit from feeding every 2-3 weeks with a “bloom-promoting” fertilizer that is low in nitrogen and high in phosphorus.

Pruning

Aside from light pruning of your blooming vines, very little pruning is necessary. The flowers should be left on the vine for their decorative purple pods (though they are mostly inedible). In warmer climates towards the end of the growing season, healthy vines can be cut back toward the end of the season and new growth will replace the old, eventually blooming, and producing more pods.

Pests and Problems

Because of their large size, rapid growth, and overall vigor, hyacinth bean vine rarely suffer from major pest or disease infestations. However, as with all plants, there are some issues to consider when they do occur.

The native long-tailed mitten moth will use the purple hyacinth bean vine (and its relatives) as a host plant. However, the small green caterpillars rarely damage the large vines of the hyacinth bean vine, and can be left to complete their life cycle.

Particularly in areas with high humidity and poor air circulation, fungal diseases can appear, although they rarely appear on the entire vine. To reduce the spread of the disease, increase airflow around the vines by pruning nearby plants, if possible, or thinning the hyacinth bean vines. Organic fungicides such as copper and neem oil can help control severe infestations.

How to Propagate Purple Lily Beans.

Hyacinth bean vines are easily propagated from seeds, which can be found at most places where fruit and vegetable seeds are sold. To start your own seeds indoors, follow these easy steps:

Soak the hyacinth bean seeds in water overnight.

Prepare seed-starting containers or trays with seed-starting mix.

Sow the pre-soaked seeds in the potting mix to a depth of about 1 1/2 inches.

Moisten the soil and place the containers in a warm, bright location. Seedlings should begin to emerge within a week of planting, but it may take up to two weeks.

Transplant the plants to the garden or outdoor pots after the third set of leaves have appeared and the plants have hardened off.

Alternatively, seeds can be sown directly outdoors in zones 10 and above, or after temperatures have warmed to 50 degrees and the danger of frost has passed.

Purple Flower Bean Varieties

There are several varieties of lily bean plants to choose from.

White Hyacinth Bean

White flowering hyacinth beans include white varieties such as 'Silver Moon' and 'Alba', and grow much like standard purple hyacinth bean vines but also have green beans and green stems, without all the purple markings.

Ruby Moon Hyacinth Bean

Very similar to the upright variety, 'Ruby Moon' flowers for a long period of time during the growing season.

Companion Plants

Because of their large size, hyacinth beans are usually grown alone, but they can be combined with other large, hardy plants. For example, some annual vines such as moonflower vine (Ipomoea alba) and black-eyed Susan vine (Thunbergia alata) can outcompete hyacinth beans.

Frequently Asked Questions

Are hyacinth beans poisonous?

Yes, the seeds of these plants are poisonous without proper preparation and should not be eaten. However, the young leaves and shoots are edible and are eaten throughout Southeast Asia.

Why aren’t my purple hyacinth bean vines blooming?

Generally speaking, if your purple hyacinth bean vines are big and full, but not blooming, there are two main reasons. The first is too much nitrogen, which produces lush growth but doesn’t encourage blooming. The second — and more likely — reason is that your plants are in too much shade to gather enough energy to bloom. Move the plants if possible, or plant them in a sunnier spot next season.

Are purple hyacinth bean vines invasive?

No, they are not considered invasive, but because of their rapid growth and large size, they can easily kill off other plants nearby.