How To Care, Grow and Bloom Hoya Plants

Don't miss a thing! Make sure you like Plant Care Today on Facebook, over 500,000 followers and growing...

hoya-plant-550

Call them the Hoya plant – climbing, clambering, creeping, or wax-stemmed plants with thick leaves.

Known as the Hindu rope plant or wax plant, Hoya has been enjoyed for decades, perhaps because fanciers enjoy their easy going indoor dispositions.

Their wheel-like clusters of waxy or porcelain flowers with stars in their crowns, are sometimes deliciously fragrant.

History Of The Hoya Plant

The Hoya was named in honor of Thomas Hoym, gardener to the Duke of Northumberland. He was the first to bring this superb house plant into prominence.

Native to southern India, where it is highly prized, and the subject of legend, hoyas are also found throughout eastern Asia to Australia. It has been classified botanically in the asclepias (milkweed) family.

The exact number of species is a mystery. Bailey’s Standard Cyclopedia of Horticulture estimates there are 100 species. The most common species, and the one most often seen and grown as a houseplant is Hoya carnosa variegata.

Thick leaves of green, rimmed with red and white, and a waxen texture from which it derives the nick-name “wax plant.”

Hoya Flowers Exquisite Creations

hoya-flower

In a sunny window the foliage is unusually decorative, and their late spring and summer flowers are highly prized.

Hoya blooms are among the most exquisite creations of nature, seemingly fashioned from ivory or porcelain, with glimmering centers of ruby and amethyst. The blossom of Hoya carnosa has a delicate, elusive fragrance which is barely noticeable.

The waxen ball of five-pointed, double stars, is geometrically perfect; giving the bloom an artificial look of. Those seeing Hoya carnosa for the first time are pleasantly surprised to find it is real.

TIP: Do not touch or move the Hoya plant during its blooming period.

Hoya Foliage: Striking, Variable

The striking foliage of Hoya carnosa variegata is quite variable, and sometimes changes as the plant matures.

The compact form – Hoya carnosa compacta is a curious variation with crumpled foliage, but it puts out one of the most spectacular blooms of the species.

Hoya Care: Pampering Not Required

Native to tropic and subtropical regions, most hoyas do equally well in homes, in protected areas or a greenhouse. The hoyas that climb do so by means of small stem rootlets, when untrained, they form a thick mat. Several species make beautiful baskets.

Lighting – a north window is a good location. Although the plants do not require direct light, they would not do well away from a window, unless you prefer to grow them under fluorescent grow lights. Supply all but the hottest sun.

hoya-varigeated-809

Soil – a moist, well-drained, light soil – African Violet soil with some added perlite – is a good growing medium.

Watering – keep the soil moist in spring and summer, dry but not to the point of shriveled foliage in winter. In dry climates more frequent watering may be necessary.

Some like to mist the leaves frequently, to clean them and increase humidity… but NOT when the plant is budding or in flower.

Temperature – give them medium (50 degrees) to warm temperatures during the growing season—spring and summer. The plants go semi-dormant in winter.

Fertilizer – In spring hoyas react favorably to feeding. A liquid food, about every four weeks, three or four times during the growing season will produce a vigorous growth. Withhold food during the winter.

Blooms appear in spring and summer when the plant is most active. Lack of water or too much fertilizer will cause foliage to brown around the edges and perhaps leaves will drop.

As with most plants, Hoyas respond to good care. However, they resent pampering, hovering, and constant handling and moving.

They have one peculiarity worth noting: their blooms are produced on knobby spurs which should stay on the plant even after blossoms fade. New buds will be generated there to provide bloom the next time. The lesson in this is that to encourage prolific blooming, leave the flower spurs on the plant.

Also, for fuller flowering, most growers recommend that the roots be pot-bound.

Hoya Not Blooming?

Question: I have an 8 year old Hoya vine, growing long vines but never has flowers. What ran I do to make it produce flowers? HB, Minnesota

Answer: Many home hoya growers cannot get their plant to bloom. Plants flourish best in bright light, in humid air, with ample moisture at the roots. But, hoyas need a break.

During winter keep the plants cool, 50 degrees, and rather dry. Continued high temperature, fertilizer (liquid), and moisture promotes leaf and stem growth and prevents the formation of flower buds.

After buds are set, the temperature may be again slightly increased.

Hoya Propagation

Propagate hoyas by cuttings of top growth, or by leaf cuttings in the same manner as African violets and gloxinias. The average cutting or leaf start will produce a blooming plant in two years or less.

The easiest method of propagation is by layering. Layers mature faster and do not need as much patience. Pin down a stem, at the joint, in a moist rooting medium. Sever and pot the new plant when roots have formed.

I have taken a mature Hoya variegata; severed and planted every leaf and stem; and in less than a year have produced 78 healthy plants! Commercial African violet soil is an excellent starting medium and I prefer small clay pots over plastic, although either can be used.

Rooting Hoya in Water

The most fetching hanging vase I’ve ever seen was a brown jug filled with rooted wax plant cuttings, all growing in water.

The glass of the jug was barely transparent. Three kinds of wax plant were used: Hoya carnosa (plain green leaves), a variegated form of carnosa and Hoya bella (miniature).

I made a similar planting, and gave the vines food by following the directions on a tub of soluble houseplant fertilizer. However, the vines will thrive unbelievably long without any food in the water.

Seeds Are Scarce

Starting seeds is almost unheard of because the blooms seldom produce seeds. It seems that pollination is a difficult business which in nature is carried out by an insect foreign to the United States.

Pest and Problems

Hoya has remarkably few pests. The worst is the root-knot nematode. Because of it the hoya is rarely grown out-of-doors in Florida and other frost-free sections where climate would permit. If there is a nematode within 100 miles, it seems to seek the hoya and destroy it.

Aphids enjoy the sweet juices of the hoya, but they are easily controlled by most common house plant insecticide sprays, Neem oil or and insecticidal soap.

Mealybugs sometimes attack and can be controlled the same as Aphids. Ants (which accompany aphids), and red spider mites can be kept away by periodic application of a malathion spray.

If you do find a hoya dying from a nematode infection, you can salvage leaf and stem cuttings to start new plants. Discard and destroy the roots and soil of an infected plant.

Hoya Species

Hoya australis – has huge, waxen, deep-green leaves measuring nearly four inches across, and splotched with silver. It is a vigorous, strong grower, vining kind with distinctly fragrant flowers, pink with red crowns.

Hoya bandaensis – Sturdy plant with deep-green glossy leaves.

Hoya bella – is a handsome dwarf, small growing species with slender upright branches that droop down as they age; a non climber, small leaves are thick, dark green; flowers are white with purple centers. An old favorite.

hoya-species

Hoya carnosa – Old-timer with shiny dark-green oval-pointed leaves, spreading sprays of faint pink flowers centered with a red star-crown. This one climbs best by sinking its aerial roots into a porous support like a moss pole.

Several variations are available: ‘Exotica,’ with green leaves centered with cream, sometimes pink-tinged; variegata, the leaves irregularly edged with creamy-white, touched with pink in sun.

Hoya coronaria – is a climber, not widely available, with waxy leaves that re-curve and are hairy beneath. It has pale lemon yellow flowers with red spots.

Hoya imperialis – Stems and leaves dusted with down, margins curled; large red-brown flowers with creamy centers.

Hoya keysi – has thick close-jointed stems and heavy, gray-green leaves covered with down, off-white flowers, red base.

Hoya latifolia (cinnamonum) – Egg-shaped coppery leaves with paler veins.

Hoya longifolia shepherdi (angustifolia) – Slender leaves indented at the center vein so they’re almost folded; delicate display of white flowers accented with bright wine.

Hoya macrophylla – Creeping species with light-veined, copper-green leaves, white flowers.

Hoya motoskei – Free-flowering vine (considered the true Hoya carnosa) has elliptical leaves of lighter green unevenly speckled with silver; with clusters of pinkish-white flowers with maroon centers.

Hoya multiflora – a stout, climbing plant, with large leathery leaves and pale yellow flowers; ‘Silver Leaf’ is a variety of multiflora with dark green leaves blotched with silvery pink.; red stems; hairy flowers the color of vintage wine, with a crown of silver-pink stars.

Family: Asclepiadaceae
Common Name: Wax Plant

Images: Top dhobern | Hoya samoensis | Hoya macgillivrayii | Hoya aldrichii | Hoya micrantha