Called the Hoya plant – climbing, clambering, creeping, or wax-stemmed plant with a thick wax leaf makes an excellent indoor houseplant like these as well.
History Of The Hoya Plant
The name “Hoya” honors Thomas Hoy (17 – 1821), gardener to the Duke of Northumberland and the first to bring this superb house plant into prominence.
Native to southern India, highly prized, and the subject of legend. You’ll find Hoyas throughout eastern Asia to Australia and 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. Listed at the end of the article are over 550 recognized species.
The most common species and the one most often seen and grown as a houseplant is Hoya carnosa and Hoya carnosa variegata.
Thick leaves of green, rimmed with red and white, and a waxen texture from which it derives the nick-name “variegated wax plant.”
Hoya Flowers Exquisite Creations
In a sunny window, the foliage is unusually decorative, and their late spring and summer flowers are highly prized.
Some consider Hoya blooms 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 carries 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. Those experiencing 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 Leaves & Foliage – Striking & Variable
The striking foliage of Hoya carnosa variegate with its succulent foliage is quite variable, and sometimes changes as the plant matures.
The compact form – Hoya carnosa compacta, a curious variation with crumpled foliage, puts out one of the most spectacular blooms of the species.
How To Care For The Hoya Plant… It Does Not Require Pampering
Native to tropic and subtropical regions, most hoyas do equally well in homes, in protected areas or a greenhouse.
The hoyas that vine and climb do so by means of small stem rootlets, when untrained, they form a thick mat.
Several species make beautiful baskets and look great on a small trellis.
Hoya Light Requirements – 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.
Soil – a moist, well-drained, light soil – African violet soil like this mix at Amazon 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. Fertilize using a liquid balanced food, about every four weeks, three or four times during the growing season will produce a vigorous growth.
Withhold food during the winter. More on applying liquid plant foods here.
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.
One Hoya peculiarity worth noting: They produce blooms on knobby spurs which stay on the plant even after blossoms fade. New buds will be generated there to provide bloom the next time. The lesson to learn: to encourage prolific blooming, leave the flower spurs on the plant.
Also, for fuller flowering, most growers recommend as a part of Hoya care of keeping the roots pot-bound.
The How To’s Of Hoya Plant Propagation
Propagate Hoya plants from 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 air-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 after roots form.
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! For an excellent starting medium try a commercial soil mix used for growing African violets. I prefer small clay terracotta pots over plastic, although either can be used.
Tips For 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. They used three kinds of wax plants:
- Hoya carnosa (plain green leaves)
- The variegated form of carnosa
- 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.
Hoya 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 most common houseplant insecticide sprays, organic sprays of Neem oil or an insecticidal soap will easily control them. Fungus gnat can at times become a problem.
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 Plant Care: Questions and Answers
What To Do When Your Hoya Is Not Blooming?
Question: I have an 8-year-old Hoya vine, growing long vines but never flowers. What can 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, Hoya plants 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 set, you can increase the temperature again slightly.
Hoya Bloom Time Lapse
Hoya Plant In Soil Not Flowering, Long Cutting Growing in Water Does Flower – Why?
Question: I have two plants of Hoya motosekei. The original plant is growing in soil. I took a long cutting and rooted it in a glass of water. It is still growing in the water, sitting on the window sill.
The plant in the glass of water blooms. The one in the soil does not. Do you have any idea why?
Answer: The first important item to remember – the Hoya flower only “shows up” on long shoots. Secondly, the wax plant flower will do best when placed next to the glass on the window sill as well.
Personally, I would pot up the blooming plant in a well-draining soil like an African violet mix. Place both plants in the window, keep them well watered and next spring you should see more blooms.
Commonly Grown 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 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.
Common Name: Wax Plant
Full List Of Hoya Species
Below is a list of 557 Hoya species, subspecies and varieties recognized by The World Checklist of Selected Plant Families at Kew as of September 1, 2017.
Readers Share Their Wax Plant Growing Experiences
by Alma Brand shares her experiences with Hoya carnosa.
During the summer my greenhouse is festooned with hundreds of coral star-clusters from the old-fashioned wax-plant, Hoya carnosa. During the winter its ovate, leathery leaves form an ornamental pattern against the roof-glass, providing protection for shade-loving plants on the bench below.
The rounded flower clusters hang heavily from the vines overhead and are not hidden by foliage. As many as fifty 1/2-inch star-shaped flowers make up one cluster or umbel. And on a plant exposed to the sun, as mine has been, these bouquets may be spaced less than 6 inches apart, borne along the vine on short peduncles or spurs in the axils of the leaves.
The vine, trained across a 6-foot section of the glass (there must be more than 150 feet of vine), gives the effect of a fragrant, star-studded bower. Its 10-inch pot placed on the sill leaves the bench free for other plants.
The first flowers fully open by late April. After a month or so, they darken and are pushed off the spurs by new buds forming. This cycle continues until the last flowers fall in late October.
Some like to pinch off old flower stems but should hold back with this plant. New blooms grow on the old spurs; and the older and longer the spurs, the larger the umbel of flowers will be.
For best bloom the plant should rest in winter, receiving only enough water to keep it from drying out. The plants seem to grow in any soil and will tolerate years of neglect, but a porous soil of peat moss, perlite and coarse sand, with a little charcoal, has served me well.
My Spectacular Wax Plant
By Clara Shattner
My wax plant, Hoya carnosa, was given to me as a small rooted cutting a few years ago. I had never seen a plant like it before but fortunately, I gave it the right care – a sunny window, water whenever the top soil seemed dry, and a pot trellis on which to climb.
The foliage is heavy, leaves are dark green with a few creamy white speckles. The entire plant shines and looks as fresh as though just sprinkled by a soft spring rain.
The white flowers have a delicate pink tinge and appear in umbrella like clusters. You have to touch them to see if they are real for they appear to be made of wax. In the very center of each flower is a tiny red wreath, which looks like a small crown.
When the flowers are mature, a liquid substance slowly forms in the center of each, and when it is as large as a tear it drops to the ground. This, and the fact that it blooms during the Lenten season, possibly account for one of its common names, tears of Christ.
There were at least fifteen flowers on my plant just before Easter last year and their sweet scent filled the house each evening. The perfume is noticeable only at night, disappearing without a trace during the day.
Cuttings are easy to start in moist peatmoss, perlite, vermiculite, or sphagnum moss. Be careful not to take too many cuttings – if you do, you’ll cut off the blooming tips and forfeit future flowers on your old plant.