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The Purple Hyacinth Bean

The purple hyacinth bean and its associated vine offer a versatile option for your home landscape.

Closeup of purple hyacinth bean pods.

In your flower garden, the plant boasts fragrant bright pink flowers giving way to equally beautiful deep purple pods. In your vegetable garden, the plant produces edible leaves, roots, and pods, although special care must be taken in cooking the beans themselves.

Read on to learn about the history, growth habits, and more regarding the purple hyacinth bean.

A History of the Purple Hyacinth Bean

The purple hyacinth bean is native to tropical Africa and is today cultivated widely in both northern Africa and Asia as an edible crop. It began appearing in European gardens in the early part of the 1700s, and by the next century, was being offered for sale in American nurseries.

Among the places the purple hyacinth bean vine was grown in early America was the gardens at Monticello, home of American founding father Thomas Jefferson.

A row of purple hyacinth bean plants.

The purple hyacinth is an annual plant, meaning that it grows from seeds planted in the springtime, moves through its flowering and bean growth cycles, and then dies, usually after frosts begin in fall. During its life cycle, the purple hyacinth bean “sets” seeds that can be used to grow the succeeding year’s plants.

Health Benefits of the Purple Hyacinth Bean

Before taking a look at the health benefits of the purple hyacinth bean, a word of caution is in order.

While immature bean pods can be cooked like green beans and consumed, there is some controversy over whether the plant’s dried and shelled beans should be eaten.

Dried purple hyacinth beans contain substances called cyanogenic glycosides that are converted by the body into poisonous hydrogen cyanide.

Purple hyacinth beans and pods.

Some sources indicate the cyanogenic glycosides can be removed by soaking the beans overnight and then boiling them twice, each time in fresh water, but other sources are skeptical of that process.

Armed with that information, you can evaluate whether consuming dried purple hyacinth beans is worth your consideration. According to one source, the dried beans contain nearly half of the recommended daily allowance of protein, are good sources of fiber, are gluten-free, and contain Vitamin B.

Cooking With the Purple Hyacinth Bean

Purple hyacinth beans are widely used in curries, with rice, and in vegetarian dishes, as illustrated by the recipes available online at Eat the Weeds.

There are other online sources for recipes using purple hyacinth beans, although they are somewhat limited. Wherever you find a recipe calling for these beans, whether for immature beans plucked from the plant, or for dried beans, pay strict attention to guidance for preparing the beans.

Growing Your Own Purple Hyacinth Beans

A purple hyacinth bean plant with pods.

Ideally grown in the far southern and western regions of the United States, the fast-growing purple hyacinth bean vine can be grown almost anywhere that the temperature doesn’t dip below 37 degrees for any significant length of time, as long as the plants get plenty of sun.

The middle of spring is the best time to plant your bean seeds. Place them directly in the garden, about a foot apart, and be sure to water them regularly, keeping the soil moist until a vigorous root system has formed.

You’ll see flowers beginning to bud in the early part of summer, and you’ll enjoy the fragrant flowers throughout the fall. That’s when you’ll want to start harvesting the colorful seed pods for next year’s garden. Otherwise, the pods will dry and fall to the ground, leading to uncontrolled growth in the next year.

A special consideration in growing hyacinth beans is the fact that fast growth can overwhelm a garden space if no plan is in place to control the vines. You can install a trellis, knowing the plants can grow to 15 feet. For a less formal look, simply allow the vines to drape over your garden fence.

Where to Buy Purple Hyacinth Bean Seeds

A hyacinth bean seedling.
A hyacinth bean seedling.

Purple Moon is a variety of purple hyacinth bean vine seeds that can be found online at True Leaf Market, one of our favorite online sources for seeds.

Harvesting Seeds

If you’ve seen the colorful flowers and pods adorning purple hyacinth bean vines in a neighbor’s garden, you might want to ask them for some seeds to start your own vines.

And going forward, you might want to learn how to harvest your own vines’ seeds, so you can have the beauty of purple hyacinth beans as part of your home landscape every year.

Briefly, here’s how to harvest bean seeds in the fall for spring planting. First, wait for the bean pods to begin drying and shriveling up. Pick them before the first frost, and store them in a cool and dry place.

As a pro tip, garden shears or scissors may make it easier to remove the pods from the vines.

After you’ve harvested the pods, you’ll need to extract the seeds. Getting at the seeds is a simple matter of squeezing the sides of the pods until they burst open, spilling out their seeds.

Purple hyacinth beans and pods.

Storing Harvested Seeds

There are a couple of methods for storing your harvested seeds through the winter. Some home gardeners simply gather the seeds into an envelope and seal it, making sure to store the seeds in a place where the temperature stays between 68 to 77 degrees Fahrenheit.

Other home gardeners prefer storing their collected purple hyacinth bean seeds in a jar, which can be sealed tighter than an envelope. If you choose jar storage, watch to ensure that no condensation forms in the jar to get the seeds wet.

For either method, it’s important to ensure that moisture and high or low temperatures won’t become a problem.

Pests and Diseases of the Purple Hyacinth Bean

Closeup of purple hyacinth bean pods.

The purple hyacinth bean is a great choice for the novice gardener because there is little need to worry about pests. One thing you may notice is butterfly eggs on the leaves, and emerging caterpillars munching on those leaves.

Japanese beetles may also be a minor problem, inasmuch as they enjoy eating the flowers and leaves of the purple hyacinth bean vine.

There is usually little danger from these pests, but if you do see signs of them, a homemade mixture of soap and water sprayed on the leaves should get rid of them.

Preventing Purple Hyacinth Bean Diseases

In terms of diseases, the purple hyacinth bean is subject to bacterial blight infection as well as fusarium wilt and rust, both fungal diseases. Blight will appear as leaf spots that eventually move to stems, while rust will make the plant look burnt, and fusarium wilt will produce yellowing of leaves.

Keeping an eye toward prevention by keeping the soil moist, and thinning vines to allow for air circulation, is usually the best strategy for dealing with purple hyacinth bean diseases.

Add Some Purple to Your Garden This Year!

Pink flowers of a purple hyacinth bean plant.
Bright pink flowers of a purple hyacinth bean vine.

As already mentioned, the purple hyacinth bean is a good choice for the gardener interested in adding beauty to the home landscape. We hope this post has inspired you to try growing it.

For more information on all sorts of beans, visit our Bean Plants page for blog posts and helpful guides.