By Susan Patterson, Master Gardener
A vigorous ornamental annual vine, purple hyacinth bean plant (Dolichos lablab or Lablab purpurea), displays beautiful pinkish-purple blossoms and interesting reddish-purple pods that grow to be about the same size as lima bean pods. The hyacinth bean plant adds loads of color and interest to any garden right through fall.
Thomas Jefferson’s favorite nurseryman Bernard McMahon sold hyacinth bean vine plants to Jefferson in 1804. Because of this, the hyacinth bean is also known as Jefferson bean. These fabulous heirloom plants are now featured at Monticello in the Colonial kitchen garden.
How to Grow a Hyacinth Bean Vine
Purple hyacinth beans are not fussy about soil type but do best when planted in full sun. These vigorous growers do require a sturdy support that is at least 10 to 15 feet high. Many gardeners grow this lovely vine on a sturdy trellis, fence or arbor.
Seeds can be sown directly outdoors once the threat of frost has passed. Seeds can also be started indoors several weeks before the weather warms. Transplants are best when planted on the small side.
Once planted, these low maintenance plants require very little care. Provide regular water for transplants and seedlings for best results.
When to Pick Purple Hyacinth Bean Seed Pods
Although purple hyacinth beans are used as a forage crop in some parts of the world, they are not recommended for eating, as they have to be cooked a very particular way. Instead, they are best enjoyed as an ornamental plant in the landscape. For those wanting to grow additional plants, the seed pods can be harvested. Therefore, knowing when to pick purple hyacinth bean seed pods is helpful.
Once the flower dies away, the pods begin to take on significant size. The best time to harvest the bean seedpods is just prior to your first frost. Seeds are easy to keep, and you can use them next year in the garden. Seeds can be easily removed from dried seedpods for storage.