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| ## yardlong bean {#yardlong-bean .Title-Header}                       |
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| *Vigna unguiculata* (L.) Walp. ssp. *sesquipedalis* (L.) Verdc.       |
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| Plant Symbol = VIUNS2                                                 |
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Contributed by: USDA NRCS Pacific Islands West Area Office and National
Plant Data Center

![](media/image2.jpeg){width="1.6875in" height="2.25in"}

University of California at Davis

Small Farm Research Center

##### Alternate Names {#alternate-names .Header-3}

*Vigna* *sesquipedalis* (L.) Fruw., Chinese longbean, yard-long bean,
judia esparrago, haricot asperge, pea-bean, asparagus bean,
Taao-hla-chao (Hmong); juro-kusasagemae (Japanese); dow gauk (Chinese);
sitaw (Filipino);

##### Uses {#uses .Header-3}

*Ethnobotanic*: Edible pods should be picked at maximum length while the
skin is still smooth, and before the seeds mature and expand. At this
tender stage, they can be snapped and cooked in stew with tomato sauce;
boiled and drained, then seasoned with lemon juice and oil; or simmered
in butter or oil and garlic. The pale green bean is meatier and sweeter
than the dark green bean, which has a less delicate taste.

The mature bean is often dried, stored, and later cooked as a pulse or
used as bean sprouts by soaking in water and allowing them to sprout.

The young leaves and stem tips are steamed and eaten as a green
vegetable.

*Commercial*: Long bean can be harvested and sold fresh at local
farmers' markets or harvested and sold to local distributors for
processing and packaging for later resale.

*Ornamental:* The large violet-blue flowers and draping pods make
yardlong bean a useful ornamental in city parks, office buildings, and
around homes.

*Wildlife:* The young leaves and bean pods are good food for deer, small
mammals, and birds.

##### Status {#status .Header-3}

Please consult the PLANTS Web site and your State Department of Natural
Resources for this plant's current status (e.g. threatened or endangered
species, state noxious status, and wetland indicator values).

#####  {#section .Header-3}

##### Description {#description .Header-3}

*General*: Family (Fabaceae). Yardlong bean pods may grow to 10-20
inches long, but customers prefer them 10-12 inches in length and
pencil-size. Although both red seeded and black seeded yardlong bean
exist, the black seeded pod is preferred for human consumption.

These unique beans grow on twining, delicate stems with 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 12 inches long in only a few days. The beans can
grow up to three feet long, ripening to pale green and inflating as the
red or black seeds ripen.

Although yardlong bean resembles pole snap beans (*Phaseolus vulgaris*),
it is botanically more closely related to southern cowpeas (*Vigna
unguiculata).* However, yardlong bean is much more a trailing and
climbing plant than the southern pea, often reaching 9-12 feet in height

Yardlong bean, a true legume, enriches the soil by fixing atmospheric
nitrogen in nodules on its roots. With the help of nitrogen fixing
bacteria, the plant makes its own food.

*Distribution*: The yardlong bean originated in southern Asia and is now
grown extensively in Asia, Europe, Oceania, and North America. For
current naturalized U.S. distribution, please consult the Plant Profile
page for this species on the PLANTS Web site.

##### Establishment {#establishment .Header-3}

*Adaptation*: Yardlong bean tolerates acid soils but prefers soil pH
range of 5.5 -- 7.5. The plant thrives in soils that are loose, friable,
and not too rich in nitrogen. Soils heavy in nitrogen can cause over
abundant leaf growth and reduced bean production. Choose a site in full
sun and loosen the soil to a depth of eight to ten inches in preparation
for sowing. Mix in compost or composted manure in spring to slightly
boost soil fertility

The plant\'s long, trailing growth habit requires a trellis for best
production. Training the vine requires labor, about as much as for
tomatoes and peas. The plant will climb by itself, but still needs some
help and a very strong trellis system. The vines will grow to the top of
your trellis, so don\'t build the trellis so high that harvesting is
made difficult. Bamboo tripods or row trellising with poles and string,
at least seven feet high are required to accommodate the vines. Various
trellising systems can be used. Yardlong bean will climb poles,
especially if they are not completely vertical and the poles are 3/4
inch to 2 and a half inches in diameter, but must be trained to poles
early during the growing season.

Yardlong bean thrives in heat and withers in cold, so sow after all
danger of frost has passed and the soil has warmed. To move the planting
schedule ahead, one can put down black plastic mulch to warm soil. If
using a tripod system, plant three or four seeds to each pole. If using
a row trellis, plant the seeds 3 to 4 inches apart in the row..Plant the
seeds two inches deep in loose friable soil or an inch deep in heavy
soil. In areas with very long growing season, make two more successive
sowings, at two-week intervals. In northern climates, a single sowing in
late spring will often produce until frost.

Seeds will germinate in about a week and the young plants will start
producing abundantly once the weather heats up. They easily tolerate hot
weather and even some drought. However, to keep the beans producing,
water in dry spells. It is unnecessary to fertilize yardlong bean unless
you have nutrient-poor soil.

This warm-season crop can be planted in a wide range of climatic
conditions, but is very sensitive to cold temperatures. It can tolerate
heat, low rainfall and arid soils, but the pods become short and fibrous
with low soil moisture. Yardlong bean prefer high temperature,
conditions under which other green beans cannot be produced*.*

*Propagation by seed*: Plant seeds in a raised bed 1 to 2 inches deep in
late spring when the soil is warm. To ensure good germination water beds
immediately after planting. Thin the young plants to 6-12 inches in the
row with 3-4 feet between rows. Since yardlong bean is a legume,
inoculate the seed with nitrogen fixing *Rhizobium* bacteria as an
alternative to using nitrogen fertilizer. If the seed is not inoculated
with a *Rhizobium,* high nitrogen fertilizer may be required when
seeding and during the growing season.

**Management**

*General*:

Yardlong bean is harvestable about two months after direct seeding or
sowing and continues throughout summer and into the fall. Harvest pods
when the beans are about half the diameter of a pencil, before the seeds
have filled out inside and when they still snap when bent. You may need
to harvest daily since continuous picking keeps the plants producing.
The plants will stop producing if beans are left to ripen. Although the
beans will keep several days in the refrigerator, they are best eaten
soon after harvesting. They can also be blanched and frozen for winter
storage.

Yardlong bean have a more dense texture than those of snap beans and
more intense \"bean\" flavor. Their texture and flavor hold up well when
stir-fried or steamed. If the beans are left to mature somewhat, they
can be shelled and cooked as other southern \"peas\".

Harvested beans develop rusty patches quickly. Keep moist while in
coolers, since dehydration in the coolers will lower quality and make
them unmarketable.

##### Pests and Potential Problems {#pests-and-potential-problems .Header-3}

Aphids, particularly the black bean aphid *(Aphis fabae*), are drawn to
the pods of this plant. Thrips tend to be a pest early in the season,
but the plants will often out grow them, especially as the weather gets
warmer and the plants grow faster. Mites can be a problem, primarily
after insecticide applications, which often lead to mite outbreaks.

##### Cultivars, Improved, and Selected Materials (and area of origin) {#cultivars-improved-and-selected-materials-and-area-of-origin .Header-3}

Contact your local agricultural extension vegetable specialist for
recommendations pertinent to your growing site.

##### References {#references .Header-3}

Abdullah, W.D., A.A. Powell, and S. Matthews 1991. *Association of
differences in seed vigor in long bean (Vigna seequipedalis} with testa
colour and imbibition damage*. Journal of Agri. Sci. 116. 259-264.

Duke, J.A. 1981. *Handbook of Legumes of World Economic Importance*.
Plenum Press, New York, New York.

Federal-State Market News Service. 1987 & 1988. *San Francisco Fresh
Fruit and Vegetable Wholesale Market Prices.* USDA and CDFA.

Fery, F.L. 2002*. New opportunities in Vigna*. p. 424--428. In: J.
Janick and A. Whipkey (eds.), Trends in new crops and new uses. ASHS
Press, Alexandria, Virginia.

Harrington, G. 1984. *Grow your own Chinese vegetables*. Garden Way
Publishing, Pownal, Vermont. 268 pp.

Knott, J.E. & J.A. Deanon. 1967. *Vegetable production in Southeast
Asia*. University of Philippines, College of Agriculture, Los Banos. 366
pp.

Lim, T. K. 199?. *Loofahs, gourds, melons and snake beans.* The New
Rural Industries. Ed.: K. W. Hyde. Canberra, Rural Industries Research
and Development Corporation**.** 212-218*.*

Stephens, James M. 1994. *Bean, yard-long Vigna unguiculata subsp.
sesquipedalis (L.) Verde*. Fact Sheet HS-562. Hort. Sci. Dept., Inst. Of
Food and Agri. Sci. University of Florida. Gainesville, Florida.

Wall, G.C., C.A. Kimmons, A.T. Wiecko & J. Richardson. *Blackeye cowpea
mosaic virus (BlCVM) in yard-long bean in the Mariana Islands*.
Micronesica 29(2): 101*-*111. \<http://www.uog.edu/up/micronesica/ \>

Yamaguchi, M. 1983. *World vegetables*. AVI Publishing Company, Inc.,
Westport, Connecticut. 415 pp.

#####  {#section-1 .Header-3}

##### You, Z., M. Marutani, & D. Borthakur. 2002. *Diversity among Bradyrhizobium isolates nodulating yardlong bean and sunnhemp in Guam*. J. Applied Microbiology 93:577-584. \<http://www.ctahr.hawaii.edu/mbbe/faculty/files/You_et_al_2002.pdf\> {#you-z.-m.-marutani-d.-borthakur.-2002.-diversity-among-bradyrhizobium-isolates-nodulating-yardlong-bean-and-sunnhemp-in-guam.-j.-applied-microbiology-93577-584.-httpwww.ctahr.hawaii.edumbbefacultyfilesyou_et_al_2002.pdf .Header-3}

#####  {#section-2 .Header-3}

##### Prepared By {#prepared-by .Header-3}

*John H. Lawrence*, Pacific Islands West Area Office, Pacific Islands
Area, Mongmong, Guam

And

##### *Lincoln M. Moore*, Formerly USDA, NRCS, National Plant Data Center, Baton Rouge, Louisiana

##### Species Coordinator {#species-coordinator .Header-3}

*John H. Lawrence*, Pacific Islands West Area Office, Pacific Islands
Area, Mongmong, Guam

##### Edited: 070212 jsp; 070322 jsp {#edited-070212-jsp-070322-jsp .Header-4}

For more information about this and other plants, please contact your
local NRCS field office or Conservation District, and visit the PLANTS
Web site\<[http://plants.usda.gov](http://plants.usda.gov/)\> or the
Plant Materials Program Web site
\<[http://Plant-Materials.nrcs.usda.gov](http://Plant-Materials.nrcs.usda.gov/)\>

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Center](http://www.usda.gov/oo/target.htm) at 202-720-2600 (voice and
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*To file a complaint of discrimination write USDA, Director, Office of
Civil Rights, Room 326-W, Whitten Building, 14th and Independence
Avenue, SW, Washington, DC 20250-9410 or call 202-720-5964 (voice or
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*Read about [Civil Rights at the Natural Resources Conservation
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