Try Yardlong Beans

Daniel Gill, Merrill, Thomas A.

Get It Growing News For 05/28/04

By Dan Gill
LSU AgCenter Horticulturist

One of my favorite summer vegetables is the yardlong bean.

This vegetable originated in southern Asia and is now grown extensively in Asia and Europe. It’s also slowly gaining popularity here in the United States, but it’s not as commonly grown in Louisiana as it deserves to be.

These unique beans, harvested in the immature stage and snapped like green beans, grow on a vine with twining stems and a tenacious root system. The plants bloom in mid-summer with a pair of large white or purple flowers. Once pollinated, the flowers are followed by tiny dark green beans that reach a foot long in only a matter of days. The beans can grow up to 3 feet long, ripening to pale green and inflating as the red or black seeds inside mature.

Although they resemble pole snap beans (Phaseolus vulgaris), yardlong beans are more closely related to southern peas (Vigna unguiculata), such as black-eyed, purple hull and crowder peas. Yardlong beans, Vigna unguiculata subspecies sesquipedalis, are called dow gauk in China, sasage in Japan and asparagus bean or yardlong bean in Europe and the United States.

Yardlong beans are easy to grow and aren’t demanding. If beds are fertile, little or no additional fertilizer is needed during bed preparation. In fact, too much nitrogen causes rampant vine growth and fewer beans. Like other legumes, they can obtain nitrogen from the air with the help of nitrogen-fixing bacteria that live in nodules on their roots.

To grow these beans, choose a site in full sun. Loosen the soil to a depth of 8-10 inches and then mix in a 2-inch to 4-inch layer of compost or composted manure.

Yardlong bean vines must be provided something to climb on. Tripods or row trellising with poles and string or netting is effective. Whatever method you choose, make the support about 7 feet high to accommodate the vines.

If using a tripod system, plant three seeds to each pole. If using a row trellis, plant the seeds 6-12 inches apart. The seeds are planted about 1 inch deep and should be up in a week or so.

Be sure to water at least every other day until the seeds germinate. Mulch as soon as the seedlings are large enough, and water the bed thoroughly two to three times a week, as needed, until the plants are well established.

As with snap beans, the commonly eaten part of this plant is the immature seed pods. You generally will begin harvesting beans about two months after sowing and continue picking over a long period. Harvest when the beans are smaller than the diameter of a pencil, before the seeds have filled out inside and when the pods still snap when bent – generally when they are about 12-18 inches long.

You may need to harvest daily, since continuous picking keeps the plants producing. The plants will stop producing if beans are left to mature.

Like snap beans, they are snapped into 1-inch to 2-inch pieces just before cooking. They also can be snapped, blanched and frozen for longer storage.

Some people think the flavor of cooked yardlong beans is similar to asparagus. They do have a more dense texture than snap beans and a more intense "bean" flavor. At any rate, they are a delicious substitute for snap beans when temperatures are too high for snap beans to thrive. Their texture and flavor hold up well when stir fried or steamed.

If the beans are left to mature on the vine, the pods will reach lengths up to 3 feet, and the seeds can be shelled out and cooked as you would other southern peas.

Yardlong beans make a great addition to a kid’s garden during the summer. Children love the long beans that may grow to be almost as long as the child is tall. Grow yardlong beans on a tripod of poles, and the young gardener can crawl inside the "teepee" and use it as a shady retreat from the heat.

A variety of other vegetables thrive in the hot summer garden. You could hardly have a southern garden without okra. Plant seeds now into well-prepared beds, spacing the seeds 4 inches to 6 inches apart and thin to a 12-inch spacing when they come up. Harvest the pods frequently while they are small and tender.

Southern peas are easy, productive and delicious. Excellent varieties include Mississippi Silver, Purple Hull, Whippoorwill, Black-eyed and Elite. They grow on short vines and do not require trellises.

Members of the cucumber family that can be planted now include cantaloupe, cassabanana, cucuzzi, luffa, mirliton (plant sprouted fruit), pumpkin and watermelon. Although squash and cucumbers can be planted now, production is difficult during mid-summer because of pest problems.

Other vegetables that can be planted now are amaranth, collards, eggplant (the long, skinny oriental types are more productive in heat), Jerusalem artichokes, Malabar spinach, New Zealand spinach, peanuts, hot peppers, sweet peppers (Banana, Gypsy), sweet potato (slips), Swiss chard, tomatillo and tomato (heat-tolerant types such as Heatwave, Solar Set and Sunleaper).

Get It Growing is a weekly feature on home lawn and garden topics prepared by experts in the LSU AgCenter. For more information on such topics, contact your parish LSU AgCenter Extension office or visit our Web site at A wide range of publications and a variety of other resources are available.


Contact:   Dan Gill at (225) 578-2222 or
Editor:     Tom Merrill at (225) 578-2263 or

4/19/2005 10:28:52 PM
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