With its white or red flower balls, composed of countless waxy star-shaped flowers, the hoya, also known as waxflower, waxplant, or waxvine, spreads tropical flair on the windowsill.
The splendor of the flowers is accompanied by heart-shaped, oval, or elongated, leathery leaves. Behind the exotic silhouette hides a low-maintenance, climbing houseplant.
It is enough to have basic horticultural knowledge for the successful care of a hoya. The basic requirement is a bright, warm location in combination with a well-drained substrate, such as orchid soil.
Furthermore, you want to provide adequate climbing support for climbing hoya. Optionally, the exotic plant can gracefully dangle its shoots from the hanging basket.
Given these basic conditions, care for the hoya requires only little effort:
- From April to October, water moderately with lime-free water.
- From November to March, water only enough to prevent the soil from drying out.
- Gently spray with soft water every 1-2 days.
- From May to September, apply a potassium-rich liquid fertilizer every 3-4 weeks.
- Break out or cut off withered flowers together with the flower stem.
Do not expose hoyas to cold drafts. Cut overly long shoots only if there is no alternative.
The tropical grace is grateful for a cooler wintering at 57-61 °F (14-16 °C) to gather strength for another flower festival.
Which Location is Suitable for the Hoya?
The hoya favors a bright, warm location with average temperatures of 64-77 °F (18-25 °C) and as high humidity as possible.
Protect the houseplant from bright sunlight with a curtain or shading in the winter garden. In the course of winter dormancy, the tropical flower beauty prefers a slightly cooler location at 57-61 °F (14-16 °C).
What Soil Does Hoya Need?
Waxflowers offered in garden centers and florists usually grow in normal potting soil, enriched with expanded clay or polystyrene beads.
But this substrate is admittedly only the second-best choice. If you want to offer your hoya perfect conditions, cultivate the exotic plant in orchid soil or coconut fiber.
In these, the roots are excellently supplied with oxygen and do not rot as quickly. Thrifty people use standard soil or azalea substrate and add perlite respiration flakes, lava granules, or polystyrene beads.
When is Flowering Time for Hoya?
From May to October, the waxflower competes on the windowsill with the garden’s flowering perennials.
Depending on the species and variety, they emit a beguiling fragrance, which – depending on the nectar flow – can be very intense.
To ensure that the hoya presents its most splendid flower dress throughout the summer, clean out wilted flower heads regularly.
To do this, just use your thumb and forefinger to break the umbels along with the flower stalk from the stem or tendril.
Pruning Hoya Properly
Cut off the withered flowers together with the flower stalk or break them out with your fingers.
The stems and tendrils, on the other hand, should not be cut with scissors. Each year they produce numerous new flowers on them, which would not develop in the course of pruning.
Therefore, if possible, do not cut back shoots that are too long, but if in doubt, install an additional climbing aid.
Watering the Hoya
In its succulent leaves, the waxflower accumulates a sufficient supply of moisture. Therefore, water your hoya only moderately with soft water.
If the surface of the substrate dries, water only until the first drops run into the saucer. After 15 minutes at the latest, pour out the water that has collected in it so that waterlogging cannot happen.
Pamper the tropical hoya every few days with a gentle spray of soft water from a hand sprayer.
Fertilizing Hoya Properly
Nutrient feeding is limited to the peak blooming period from May to September. During this period, administer a liquid fertilizer for flowering plants every 3-4 weeks.
Preferably, choose a potassium-rich product that is tailored to the desire for an acidic soil value.
Waxflower is susceptible to infestation by mealybugs. If the cotton ball-like webs appear on the leaves, deal with them with a neem oil preparation.
Alternatively, control the pests with cotton swabs soaked in high-proof alcohol or methylated spirits.
From October, the abundance of flowers decreases significantly, as the waxflower prepares for the coming dormant period.
The following care will help the hoya get through the cold season in good health and vigor:
- Stop feeding nutrients from October to March.
- Water only enough so that the soil does not dry out.
- Continue to spray every few days with lime-free water.
- Place in a bright place with cooler temperatures of 57-61 °F (14-16 °C).
At the end of the winter break repot the waxflower into the fresh substrate. Now the temperatures may rise again, to which you adjust the amount of watering proportionally.
If the nutrient reserves in the pre-fertilized substrate are used up after 4-6 weeks, administer a lime-free liquid fertilizer every 3-4 weeks until September.
For the propagation of additional hoyas, two methods have proven to be most effective. On climbing hoya species, lower a vital shoot into an adjacent flower pot with a lean substrate.
Slightly scratch the tissue with a razor blade and secure the sinker with a stone. Once an independent root system has formed, separate the offshoot and mother plant with a smooth cut.
The propagation of cuttings is just as uncomplicated. To do this, cut off some shoots with 3-4 leaves just below a leaf node in March/April.
Placed in peaty sand in a warm and humid microclimate under a plastic cover, the rooting progresses rapidly in a warm, semi-shaded location.
Keep the soil slightly moist with soft water. After 6-8 weeks, you can safely remove the cover and repot your seedlings into a substrate for adult waxflowers.
How Do I Report a Hoya Properly?
Do not repot an adult waxflower until the roots are already growing out of the soil opening or pushing through the substrate. The best time to do this is in early spring when winter break is coming to an end.
Here’s how to do it right:
- The new pot should be no more than 1 inch (3 cm) larger in diameter.
- Place one or more shards of clay as drainage above the bottom opening.
- Above it fill a first layer of the substrate.
- Only now pot up the waxflower to shake off the discarded soil.
Place the hoya in such a way that the previous planting depth is maintained. Water only a little until the water runs out of the bottom opening.
In a semi-shaded, warm window spot, allow the hoya to recover from the stress. If the procedure takes too much out of your waxflower, this year’s bloom may fail.
Do not let this bother you, but continue the usual care protocol unchanged. The flower will put on its graceful flower dress again no later than the following year.
Is the Hoya Poisonous?
As the toxicologists of the University of Zurich in Switzerland found out, the waxflower does not pose any danger to humans.
In contrast, the plant proves to be highly toxic to birds. Even the consumption of small quantities has fatal consequences.
Moreover, cultivation within reach of dogs, cats, or rodents should be treated with caution. Do not allow your pets near a hoya, as ingestion of the flowers and leaves can result in unpleasant symptoms of poisoning.
My Hoya Does Not Bloom
If the longed-for flowers fail to appear, various triggers could be responsible for the dilemma.
In the following we have compiled the most common causes for you with tips on how to remedy them:
- Lack of light: Place the waxflower in a bright location with 10-12 hours of daylight.
- Cold: During the growth and flowering period, ensure warm temperatures of 64-77 °F (18-25 °C).
- Waterlogging: Water all hoya species only moderately and preferably spray them more frequently with soft water.
- Overfertilization: In a pre-fertilized substrate, administer the first liquid fertilizer after 6 weeks at the earliest.
- Pruning: If possible, do not prune a waxflower, as it will bloom again and again on its tendrils.
- Change of location: If possible, do not carry the plant back and forth or turn it frequently.
- Lack of winter dormancy: From October to March, place the plant in a cooler place at 57-61 °F (14-16 °C). Water the plant less, and do not fertilize it.
Bud drop is particularly devastating, as flowering already seemed within reach. The trigger for this misery is a place under full sunlight.
At least a close-meshed curtain should protect the waxflower from the midday sun.
Faced with brown leaves on a waxflower, we mostly guess drought stress.
In fact, the hoya responds to waterlogging and root rot with this pattern of damage. Repot the hoya immediately into dry substrate and water only moderately from now on.
Yellow leaves are a classic symptom of leaf chlorosis. Waxflowers exhibit this pattern of damage when watered with hard water or kept in a calcareous substrate.
Since all hoya species require an acidic pH, too much lime will trap important nutrients in the substrate, such as iron and magnesium.
Switch the water supply to soft rainwater or decalcified tap water. Use bog bed or rhododendron soil, orchid substrate, or uniform soil as a substrate.
- Red Button: Spherical flowers with numerous dark red single flowers rise above silvery speckled leaves.
- Mathilde: Beautiful waxflower with white star florets adorned with a purple corona above oval leaves.
- Krimson Princess: Creamy green edged decorative petals underline pink flower spheres.
- Hawaiian Purple: Umbel-like spherical flowers in rich dark red tower above leaves up to 5 inches (12 cm) long.
- Stargazer: A floral jewel with white-red flowers, a beguiling honey scent and mighty, leathery leaves.
- Hoya bella: Compact waxflower with upright, later overhanging shoots and white-red flowers.