How to Grow and Flower Indestructible Hoyas
By Laurelynn Martin and Byron Martin
|Fragrant Grape Hoya
The genus hoya, commonly called Wax Plant, is a large group of mostly climbing or trailing vines, or sometimes shrubs native to tropical Asia, the Pacific Islands and Australia.
They are most often found growing as epiphytes in tropical forests where they climb up into or hang from the branches amongst the mix of other epiphytic plants. As they often grow lower in the canopy, as well as at the tops of the tress, they have a great adaption to varying light levels.
Hoyas as Indoor Plants:
Hoyas are famous as indoor houseplants because they can tolerate very dry conditions. This comes from their epiphytic nature where they can go through a dry season with little, if any, rain for months at a time, surviving on the air moisture and dew at night. When given favorable growing conditions, they will flower with a wide variety of colors and flower sizes from the tiny ¼” in diameter for each flower to the giants up to 4” in diameter per flower. The blooms often form clusters or umbels of many flowers although some are singular. Some hoya flowers have a waxy appearance; others are fragrant.
|Giant Wax Plant
They prefer a partial sun exposure generally avoiding the hot noonday sun. If given too much sun, their leaves will bleach yellow. They also will grow under shady conditions but in some cases this will reduce their flowering.
An east or west exposure is optimum for flowering and growth.
Because of their epiphytic nature they prefer a period of dryness between waterings with the soil surface getting visually dry and then a thorough watering. However, they can go for weeks and even months without watering, which makes them one of the indestructible houseplants that can take the neglect often found with the casual indoor gardener.
|Cinnamon-Scented Wax Plant
For the most part, flowering is seasonal, usually during the longer days of the year. Some plants respond to day length, like Hoya nummulariodes, a fall bloomer, while others like Hoya lacunosa flower during the spring and summer months under the higher light intensity and longer days. Still others like Hoya serpens, which comes from higher elevations, need cooler temperatures to help induce flower buds. In some cases the plants simply need to be older and larger to initiate flowering.
Trouble shooting flowering:
If you have a plant that hasn’t flowered and is quite old, try subjecting it to a dry, cool period during the winter while increasing the light level.
Unique Characteristics: Hoya lauterbachii wants to ramble 8 to 12’ before it decides to bloom. The flowering initiates on spurs that form at the leaf axis on the growing tips. Hoya carnosa, once the flowering spur forms, the spur will hold on and re-bloom many times, year after year. Hoya lanceolata bella or Hoya odorata the spur falls off after blooming and re-initiates again during the next flowering cycle.
Hoyas are quite adaptable to various potting mixes as long as they are porous and well drained. It is often said that they like a sweet soil yet we grow them in a slightly acidic mix with a pH of 6 and they do quite well.
|Hindu Rope Plant ‘Crispa’
Hoyas benefit from regular fertilization. A balanced fertilizer given in the water once a month from spring to fall is usually adequate for growth and flowers. Remember the rule of thumb, the more light exposure they get, the more fertilizer they use. So if you are growing them in a shady area, go easy on the feed. A granular organic fertilizer sprinkled on the top of the potting mix a couple of times a year is an easy way to fertilize. As with many flowering plants an occasional fertilizing with a higher phosphate fertilizer like a 5-10-3 or even a 15-30-15 will help encourage blooming. If you are using a blossom booster fertilizer, do it in the spring but not on a constant basis.
The greatest insect problems are mealybugs, which seem to love hoyas. It’s important to keep an eye out for them and spray with neem oil several times with a good forceful sprayer to bring them under control. Spider mites and thrips will affect a few varieties. Hoya lanceolota bella is notorious for attracting both.
Root disease is a problem when plants are grown under wet conditions. As these plants do well in an open, airy and dryer potting mix, a heavy, wet potting soil along with cool temperatures can cause root systems to collapse and plants can be lost.
|Miniature Wax Plant
(Hoya lanceolata bella)
Pruning is usually done to maintain size but remember that many varieties will re-flower off old spurs so a hard pruning will reduce the seasonal blooms. The best time to prune is in late winter or early spring, just as they start their seasonal growth spurt.
As they often ramble around a growing area, the vines need to be retrieved and brought back to the stake or plant itself for containment. We often grow hoyas in hanging baskets and the plants are periodically wrapped around themselves, which allows them to be contained and managed.
With a little attention, hoyas can give years of enjoyment with their waxy, sometimes fragrant, flowers and their green vining foliage that does well in low light.