Ipomoea macrorhiza (pink moonvine, large-root morning glory)

Ipomoea macrorhiza has beautiful nocturnal flowers and an edible root. It is a true perennial; the vines go dormant in the winter and sprout from the short stem at the top of the root in the spring.

The vines twine around upright supports as they grow, and seem to do little branching. They start blooming at a height of about 6-7 feet. This species will also grow as a groundcover if there is nothing to climb on.

Flower buds often appear in clusters at each node. The buds at a single node generally do not open on the same night, instead blooms will be scattered along the vine each night during the bloom period. Flowering occurs in late summer.

The pale pink flowers are about 4 inches across, and have a purple throat. The deep tubular throat is nearly as deep as the flower is wide. There is no detectable scent.

The triangular leaves have a crinkled appearance, especially when young. The furled leaves and growing tips appear white.

Native Americans cultivated this plant for its large, starchy roots.

During the dormant season, the root can be harvested and eaten, either raw or cooked. Its flavor, color and texture is nearly identical to jicama.

The dry, brown seedpods contain several fuzzy seeds.

Even seedlings only a few weeks old already have a thick, elongated root.

Ipomoea macrorhiza is native to the Southeastern U.S. It is recommended for USDA Zones 7-10.

This species is also known as pink moonvine and large-root morning glory.

Dioscorea bulbifera, edible air potato

The information contained in this post is entirely about the edible cultivated varieties of Dioscorea bulbifera. The wild air potatoes you find growing in the woods are NOT edible.

This is one of the true yams that are tropical in origin. Yams are twining vines that quickly climb to the top of any available support. They can completely cover nearby trees or shrubs so plant it in an appropriate location.

While the plant is in active growth it will put out aerial tubers at many of the leaf joints. These aerial tubers are peeled and boiled as a vegetable.

The aerial tubers will grow where they fall on the ground, so pick them up and eat them if you don't want more vines taking over your garden!

Dioscorea bulbifera will produce well in sun or light shade. The plants are very drought-tolerant once established. They are perennial in regions where the ground soil doesn't freeze during the winter. In colder locations they can be grown as an annual, saving some of the aerial tubers for replanting each year.

There are a few different cultivated varieties in circulation;

'Hawaii' has dark, rounded tubers with a bumpy skin and glossy sheen.

'Africa' has gray, angular tubers with a rougher texture.

Dioscorea bulbifera is considered an invasive species in Florida and some other southern states, but the agricultural laws do not differentiate between the wild air potatoes and these cultivated edible varieties. Here is a photo of the wild variety for comparison:

In an effort to keep wild air potatoes under control, Florida has introduced an invasive beetle from China to eat the leaves and aerial tubers.

This initially seemed to have an effect since the leaves quickly became riddled with holes by the feeding beetles, but the air potatoes have sprouted again every spring with no apparent decrease in vigor. In addition, the beetles appear to be parasitized by some other insect which reduces the beetle population.
The beetles feed on both the wild air potatoes and the edible cultivated varieties. They have also been found feeding on other species of plants. Here's one feeding on Quisqualis indica:

This may yet prove to be another example of an intentionally imported species having unforeseen consequences in its new environment.

Giant Vine Fern (Stenochlaena tenuifolia)

Giant Vine Fern (Stenochlaena tenuifolia) is an impressive species with large fronds up to 4 feet in length. It makes an excellent tall groundcover for large areas under trees, or a lush background planting for other colorful or flowering plants.

The leaves have heavy substance and are long-lasting as cut greens in floral arrangements. Young fiddleheads are edible if cooked until tender.

Once established, this fern spreads by rhizomes that run along the soil surface. The rhizomes are also able to climb trees, preferably those with rough or fibrous trunks for easier attachment.

Mature specimens of Giant Vine Fern grow a few specialized fertile fronds that produce spores, by which this plant can be propagated, although it's much simpler and faster to use sections of the rhizome. In the next photo you can see a thin, fertile, spore-producing frond compared to the typical foliage.

Here's a closer view of the spores:

This species will grow in sun or shade, and wet or dry conditions. The foliage looks best with at least a little shade in tropical regions. In the sunniest locations moist soil is preferred. I've never had to provide any irrigation beyond our natural rainfall when growing it in morning sun. Its tolerance for adverse conditions also make it a good houseplant.

Stenochlaena tenuifolia is native to equatorial Africa, and is recommended for USDA Zones 9-11. It can be container-grown anywhere.

Buy a rhizome section for planting here!

Sword bean (Canavalia gladiata)

Everything about the sword bean (Canavalia gladiata) is impressive. From the time the first true leaves emerge from the seed, until the pods split open to reveal their giant pink seeds, there's something awe-inspiring about this plant.

The pink seeds are about the size of a quarter, and get even larger if soaked before planting.

The cotyledons are pulled up out of the ground as the roots head downward, and when the first true leaves emerge, they can be 6-8 inches in diameter. Here's a seedling next to a 4-inch pot for scale:

From there, they quickly shoot up and start twining around, looking for something to climb on. Yes, this bean is a climber, so give it a sturdy support that will endure throughout the growing season. I like to grow them on dead trees, since many types of garden supports will collapse under the weight of the vines.

By mid-summer, the lavender-pink flowers appear in clusters all up and down the vine.

If pollination is successful, the bean pods start to develop, and eventually reach over a foot in length. It takes about 90 days from planting for the beans to reach a maturity at which they can be picked and eaten.

For fresh eating, the pods should be picked while they're still tender, and before the beans start to swell up too much inside. At that stage, the pods can be sliced cross-wise and boiled until tender. Discard the cooking water.

If you wait too long to eat them fresh, just let them finish maturing until the pods are dry. It will take an additional 2-3 months of growing to get to this stage.

Then the beans can be shelled out and cooked, but require soaking overnight and thorough cooking in  2-3 changes of water to rid the beans of potential toxins. For this reason, they are usually picked and eaten when the pods are still tender.

Velvet bean (Mucuna pruriens var. utilis)

Velvet bean (Mucuna pruriens) is a legume with numerous health benefits. The plant grows as a vine so some sort of support is needed when growing it in the garden.

The vine climbs by twining around adjacent supports, but the stem remains thin all the way to the base of the plant, even though it may reach 15-20 feet in height. Leaves are tri-foliate.

This is a nitrogen-fixing legume so it has low nutrient requirements, and may benefit other inter-planted crops.

Purplish flowers appear in pendant clusters starting in mid- to late summer.

The pods swell quickly and are dark green covered in black fuzzy hairs. In some varieties these hairs are skin irritants that make shelling the beans a literal pain, but the cultivar M. pruriens var. utilis is the non-itchy variety.

At the end of the growing season the vines dry up and the pods turn completely black and hard (2-3 months after flowering). The pods retain the velvet-textured covering even after they are dried and each contains 5-6 seeds.

At this point the beans can be shelled out for home use. Seed color varies with the different cultivars and may be white, black, marbled or speckled.

Treatment to make the seed edible is by boiling in water for one hour, pressure-cooking for 20 minutes, or soaking in water for 48 hours and then boiling in water for 30 minutes. The beans can also be roasted and ground to make coffee; in some parts of Central America the plant is known as Nescafe!
In some regions velvet bean is used as a green manure or cover crop in fields. It can also be harvested for forage or silage.

Mucuna pruriens is native to southern China and eastern India. The plant requires a 6-9 month growing season to mature the seeds, so it is best suited to subtropical climates if you are growing it for the beans. It can be grown anywhere as a cover or forage crop.

The health benefits of velvet bean have been widely studied. The findings reveal "it is a good source of food, as it is rich in crude protein, essential fatty acids, starch content, and certain essential amino acids ... all parts of the Mucuna plant possess medicinal properties. The main phenolic compound is L-dopa (5%), and M. pruriens seeds contain some components that are able to inhibit snake venom. In addition, methanolic extracts of M. pruriens leaves have demonstrated anti-microbial and anti-oxidant activities in the presence of bioactive compounds such as phenols, polyphenols and tannins, and preliminary studies on keratinocytes support its possible topical usage to treat redox-driven skin diseases. Collectively, the studies cited in this review suggest that this plant and its extracts may be of therapeutic value with regard to several pathologies..."

A more detailed listing of the health benefits of Mucuna shows it is effective for diabetes, spasms, inflammation, infertility, pain, growth hormone deficiencies and as an aphrodisiac.

Buy velvet bean seeds here!

Tindora (Coccinia grandis)

Coccinia grandis is a perennial cucurbit commonly known as tindora or ivy gourd. The striped fruits are about 2 inches long and are edible raw or cooked. When approaching maturity, they start turning red from the inside out, and from the distal end of the fruit to the stem.

They are edible while still green and have a crunchy texture. As they turn red, the fruit becomes sweeter and very soft.

They make a very attractive addition to a vegetable tray. Young leaves and stems are also edible after cooking.

Even the thick roots are edible after cooking, and have a delicious flavor.

Tindora is a climbing vine which attaches itself by tendrils. The leaves are palmate and about 3 to 4 inches across. Vines can grow up to 9 feet in length, branching at any point along the stem, and rooting if they touch the ground.

Flowers are white, open for a single day, and are about the same size as the leaves. Flowering and fruiting can occur nearly year-round in frost-free climates, but it is most productive during the warm months when the plant is in active growth. Male and female flowers occur on separate plants. The time from flower to harvest is about 2-3 weeks.

Coccinia grandis is native to tropical Asia and Africa, and is recommended for USDA Zones 8-11 (perennial in the coldest zones and evergreen in frost-free areas). It will grow in nearly any soil type, and needs full sun to be most productive.

Unharvested fruits drop seeds, and over time the offspring can become invasive. It has naturalized in tropical regions around the world, and is listed as a noxious weed in Hawaii and Western Australia.

There is a sterile cultivar that is preferred for home gardeners, and this is the variety that I grow. It produces parthenocarpic fruit, so no male plant is required. The seeds you see in the photo of the cut fruit above never develop fully, and are not viable.

According to WebMD, research suggests tindora might improve blood sugar control in patients with type 2 diabetes. Studies have also shown Coccinia grandis has anti-cholesterol, anti-inflammatory, anti-ulcer and anti-oxidant properties.

The dormant bare-root crowns are available for purchase during the winter months. The potted plants are available at my local markets year-round.
Buy tindora crowns here!

Jicama (Pachyrhizus tuberosus)

Jicama (Pachyrhizus tuberosus) is tropical vining legume that forms a large edible root. The vines climb by twining and can reach a length of 20-30 feet, given sufficient support. The trifoliate leaves are opposite on the stem and can be up to 18 inches across. As a legume, this plant is capable of nitrogen fixation and therefore has low fertilizer requirements.

Flower buds start to appear in the leaf axils by late summer.

These quickly open into bright blue pea-like blossoms as the inflorescence elongates.

For maximum root production you should clip off the flower buds as they form so all the plant's energy goes into the storage root, rather than seed production. The root continues to increase in size as long as the vine is green and growing, so a long growing season is also beneficial for maximum production. Note that all parts of the jicama plant should be considered poisonous except the root, even though stems and leaves are used as animal forage in some regions.

Each pollinated flower develops into a bean-like pod.

The pods grow to about 5-6 inches in length over a 2-3 month period, turning dark brown or black as they reach maturity.

When they have fully dried, the pods split open to release the seeds.

By this time the vines have also started to dry and decline and you can dig the edible root. Each vine produces a single, sometimes lobed, storage root, which varies in size and shape. Roots can become quite large, often weighing several pounds, but smaller ones are much more common.

They have a thin tan skin and a crisp white or sometimes yellow interior, depending on the cultivar. Jicama may be eaten either raw or cooked, and they retain their firm crunchy texture even after cooking.

Peel and slice the root in salads, soups and stir-fries or serve with fruits. Cut into sticks and use with your favorite dips. Jicama is a very good source of vitamin C and also a good source of potassium. The root contains oligofructose inulin, which is a sweet inert carbohydrate that is not metabolized by the human body, so is a good sweet snack for dieters and diabetics. Oligofructose is also prebiotic.

Harvested roots should be stored in a cool dry location, but not refrigerated.

Pachyrhizus tuberosus is native to Central America, but is cultivated in tropical and sub-tropical regions around the world. The closely-related P. erosus is similar except with a smaller root and is the species more frequently grown on a commercial scale.
Technically, jicama is a perennial in USDA Zones 10-12 and a new vine will sprout from unharvested roots, but it is normally grown as an annual and harvested after the first growing season. I've been more successful growing a new crop from seed each year, rather than letting the old roots sprout again. A harvest can be obtained anywhere with a growing season of at least 5 months.

Propagation is by seed. Soak the seed in water overnight before planting. Any seeds that don't show signs of swelling can be nicked with the edge of a sharp knife and soaked for a few more hours. Keep the seedbed warm and moist. Germination should occur within 2-3 weeks.