Wednesday, September 16, 2020

Alpinia hainanensis

Alpinia hainanensis is a large, fast-growing species of ginger. At first glance, one might assume it is a shell ginger, but there are several key distinctions. 

This species grows about 6 feet tall and tolerates sun or shade. Flowers appear in spring at the top of all mature canes. The inflorescence is an arching cluster of a couple dozen flowers, opening in sequence. 

The floral buds are soft pink and open to reveal a reddish throat and large, bright yellow lip marked by red striations.

Pollinated flowers develop into round green fruits that develop over the summer. 

By late summer, the seedpods mature and turn bright orange. They keep good color throughout the winter. It is these orange fruits that are grated and used as a cardamom substitute.

Alpinia hainensis multiplies by long rhizomes that spread out underground from each cane. 

This results in a fast-spreading plant with canes spaced a foot or more apart. The canes are evergreen and will live for several years.

The leaves are about 30 inches long, and glossy, with distinctive ruffled edges. The leaves and stems are highly fragrant when brushed against.

The native region of Alpinia hainanensis is south-east Asia. It is one of the hardiest of the Alpinias, surviving underground in USDA Zone 8, although flowering won't occur where the canes freeze back.

Propagation is normally by division of the rhizomes, but it is also easily grown from seed.

There is a horticultural cultivar sold under the name 'Pink Perfection'.

Tuesday, September 24, 2019

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.

Tuesday, July 11, 2017

Senna mexicana var. chapmanii (Bahama senna)

Among all the species in the Cassia/Senna group, Senna mexicana is one of the most desirable to grow. It flowers nearly continuously throughout the year, providing plenty of color in the landscape. It also generally grows no more than 3 to 4 feet tall, making it easier to manage in small landscapes and butterfly gardens.

Yes, this is a great butterfly plant, serving as a larval food plant for the Cloudless Sulphur, Orange-barred Sulphur, and Sleepy Orange butterflies.

Senna mexicana is native to Central and South America, the Caribbean, and South Florida.
It is recommended for USDA Zones 9b - 11, but stays small enough to be container-grown anywhere.

It will grow in full sun to light shade. Although flowering is probably best in full sun, mine bloom well with only a couple of hours of late-afternoon sunlight.

The evergreen leaves are alternate and pinnate. Flowers are followed by flat, dry pods that turn brown when mature.

Established plants are drought-tolerant, and they are also salt-tolerant, making this a good choice for coastal plantings.

Propagation is usually by seed.

Monday, May 15, 2017

Rose apple (Syzygium jambos)

Syzygium jambos is a small tree or large shrub bearing delicious yellow fruits with the flavor of rosewater.
The yellow blooms are borne in clusters at the ends of the previous season's growth. In subtropical locations flowering usually occurs in spring. The flowers consist of numerous stamens and one stigma, and the trees are quite showy when in bloom.

The clusters of yellow fruits ripen 3 months after flowering. Individual fruits are about an inch in diameter. When fully ripe they will drop from the tree, but they can be picked once they have turned from green to solid yellow.

The fruits are hollow and usually contain 1 or 2 seeds. The flesh is slightly crunchy and somewhat dry, but with an amazing aroma and flavor reminiscent of rosewater. They are usually eaten fresh, but can also be made into jams, jellies, or syrup.

The seeds are dark brown, and have a rough, almost sandpaper texture.They are poly-embryonic and may produce 1 to 3 seedlings from each seed.

Syzygium jambos grows to about 18 feet tall, often with multiple trunks. Some specimens get much larger. Leaves are opposite, lanceolate, and about 8 inches long by 2 inches wide.

New growth is a coppery-red color, gradually turning dark green as the leaves harden off.
The bark on the trunk is gray and slightly furrowed.

This species is believed to be native to Southeast Asia, but is grown in tropical and subtropical climates around the world. It is recommended for USDA Zones 9b-11.

Propagation is generally by seed, but air-layers are also possible. Cuttings have a low success rate.

Syzygium jambos is commonly known as Rose Apple.

Friday, February 10, 2017

Zamia maritima (cardboard plant)

Zamia maritima is a cycad, a taxonomic branch that has existed virtually unchanged since the time of the dinosaurs. Its thick, firm leaflets are the reason it is often known as cardboard plant.
The leaf petioles are covered with numerous stiff prickles.

The natural spread of mature plants is about 4 feet tall and 6-8 feet wide, so give them some room in the landscape. Although the leaves can remain on the plant in good condition for several years, each year sees just one flush of new leaves all at once.

On young plants the leaves grow in a rosette around a single growing point, as in the first photo.
As it matures, the plant has a clumping growth habit, and increases in diameter by splitting off new growing points, each with their own rosette of leaves. This is the same plant 5 years later:

The individual plants are either male or female, and can be identified by their blooms, which appear in early summer.

Male plants produce slender, upright, tan/brown cones.

Female plants produce cones that are fatter, and with larger segments.

Male plants produce their cones in large quantities, and male plants also tend to form more offsets.

The seeds develop inside the cone for 7-8 months, then the cone splits open to reveal the bright red, glossy fruits.

The fruits are toxic to dogs. If you are concerned about your pets, plant male specimens, or remove the female cones any time before they split open.

Zamia maritima is native to Mexico, and is recommended for USDA Zones 9-11. It will grow in sun or shade, and also makes a durable houseplant. This species is drought-tolerant, as well as salt-tolerant, and can be used in beach-side plantings.

Propagation is by seed.

Friday, December 23, 2016

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.

Thursday, January 28, 2016

Water chestnut (Eleocharis dulcis)

Eleocharis dulcis is commonly known as water chestnut or Chinese water chestnut. The edible part of the plant is the underground corm, which is typically harvested when the plant dies down in the fall.

Prepare water chestnuts for eating by peeling away the brown covering on the corm. Inside you'll find the white edible portion. It can be eaten raw or cooked.

Water chestnut prefers to grow in boggy soils, or submerged under a few inches of water. The hollow leaves grow to about 1.5 feet tall, giving it a grassy appearance.

Water chestnuts are easy to grow in backyard ponds or water gardens. Even a 5-gallon bucket will do. Simply plant them in the spring and they will continue to multiply throughout the growing season. Here's the result of one season of growth in a 10-inch diameter pot:

Eleocharis dulcis is native to Southeast Asia and Australia. It is perennial in USDA Zones 8-11. In colder regions, the corms can be dug and stored in wet refrigeration for the winter, then re-planted in early spring. A full sun or mostly sunny location is preferred.

Here's a short video on growing and harvesting water chestnuts from a 5-gallon bucket:

Friday, December 18, 2015

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!

Thursday, October 29, 2015

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.