How to Grow and Care for Hoya Plant

Hoyas, also called wax plants, porcelain flowers, or honey plants, are an Asian native plant related to milkweeds with fragrant, low-maintenance tropical flowers that grow in a ball-shaped cluster. The plants produce woody stems with waxy leaves, which remain evergreen.

You can train a hoya plant as a vine, or allow it to trail over the side of the container. Either way, expect the full length or height of the plant to be 2 to 4 feet. Hoyas require bright, indirect sunlight for up to six hours daily, moderately moist, well-draining soil that should dry out between waterings, humidity, or regular misting, and well-balanced fertilizer monthly.

Hoya Care

Here are the main care requirements for growing hoyas:

• Plant outside in spring or early summer in a spot with bright, indirect light.
• Place your hoya plant in a hanging basket or allow it to cling to a small trellis, providing a vertical accent in your tropical container garden.
• Give the hoya plant humid conditions, which can include placement next to a pond, fountain, or other water feature.
• Prefers moderately moist, well-draining soil; allow it to dry out between waterings.
• Give balanced, slow-release fertilizer once monthly.

Light

Hoyas thrive best when they get bright, non-direct sunlight for at least two to six hours per day.

Soil

Hoyas like to be planted in a well-draining, lightweight soil mix with a slightly acidic to neutral pH (6.1-7.5).

Water

Hoyas should be watered weekly and left to dry completely between waterings. If they get too much moisture, the roots will rot.

Temperature and Humidity

As a tropical plant, hoyas thrive in warm and moist, humid climates.

Fertilizer

Hoyas should be fertilized monthly; The International Hoya Association suggests feeding them with a fertilizer that includes nitrogen, phosphorus, and potassium.

Types of Hoya Plants

Hoya is an Asian native plant introduced by Scottish botanist Robert Brown and named in honor of the 18th-century botanist Thomas Hoy.

• H. Archboldiana: Cup-shaped creamy flowers with a maroon corona
• H. Compacta 'Indian Rope': Pale pink flowers and curly leaves; pretty even when the plant isn’t blooming
• H. Cumingiata: Yellow flowers with red corona; fragrant
• H. Kerrii Variegata 'Sweetheart Plant': Heart-shaped foliage with white margins; yellow and orange flowers
• H. Onychoides: Purple flowers with an exaggerated star shape
• Hoya Australis: Rounded, oval-shaped leaves, long climbing vines, and fragrant white flowers.

Pruning

Hoyas are slow to moderate growers. When your hoya plant finishes blooming, leave the flower stalk, as it may produce new flowers. Removing the stalk forces the plant to produce a new stalk, which delays blooming and wastes the plant’s energy. Hoyas are light feeders, and a monthly drink of compost tea or diluted fish emulsion provides all the nutrition these tropicals need.

Propagating Hoya

You can propagate hoya plants by doing stem cuttings and rooting them in soil or water. They don't need much beyond the well-draining soil and the warm, humid conditions many tropical flowers crave.

You can grow the hoya outdoors if you live in USDA growing zones 10-12; elsewhere, you must grow it as a tropical container plant or greenhouse specimen. Choose a location with full to partial sun. Plants that receive less than a half-day of sunlight may not produce flowers. Here's how to propagate via cuttings:

1. You need pruners, rooting hormone (optional), potting soil, a hand shovel, and a sterile container.
2. Take a 4-inch cutting from softwood, cut on a diagonal with at least two leaves at the top. The cutting should have at least two nodes for roots to grow from.
3. Optionally, dip the cut end in the rooting hormone mixture. Place the cut end down in a glass of filtered water. After about four weeks, roots should appear.
4. Plant the roots in moistened potting mix and place them in a spot that gets at least six hours of sunlight.

How to Grow Hoya Plants From Seed

Seeds may be started in pots or flats. Here's how to propagate from harvested or fresh seeds:

1. You'll need a good quality soilless potting mix enriched with perlite or pumice, a potting container or flat, and a clear plastic bag.
2. Make inch-deep holes into the potting mix, place one seed, and cover over with a thin layer of potting mix.
3. Lightly moisten the soil and cover the tray with a plastic bag to give the plant a humid, greenhouse-like atmosphere.
   
4. The seeds should germinate within 7 to 10 days.
5. Once the plant develops true leaves, after about a month of growth, repot it.
   

Potting and Repotting Hoya

Hoyas like the security of a snug pot, and plants that are a bit root-bound will flower more prolifically than those in a giant pot. Hoyas don’t like wet feet or heavy soil. Many grow as epiphytes in nature (similar to bromeliads and orchids). Mix your regular potting soil with orchid potting mix in a 1-1 ratio to provide an ideal growing medium for your hoya plant.

Also, when repotting, use pasteurized soil or growing medium in either new pots or those washed in a chlorine bleach solution and water.

Overwintering

Hoyas will bloom throughout the summer months. As tropical plants, they cannot endure frost or freezing temperatures. To keep them alive, bring them indoors when temperatures drop below 50 degrees Fahrenheit.

Common Pests and Diseases

Hoyas are vulnerable to sap-sucking pests like aphids, mealybugs, and spider mites. All can be controlled with neem oil. Once you've treated the plant, wipe away pest residue with a clean, soft cloth.

Fungal infections are also common diseases for the hoya. Botrytis blight can cause rot and kill your plant; it shows up as greyish patches. Treat with fungicide, and repot in sterilized potting medium.

How to Get Hoyas to Bloom

Hoyas are reliable warm-weather bloomers, but they need the right soil, ample light, adequate water and humidity, and nutrients. Fertilizer higher in phosphorus tends to improve bloom. It can also take two to seven years to reach maturity and bloom.

Bloom Months

Hoyas can bloom from June through September.

How Long Do Hoya Plants Bloom?

Hoya flowers last for about a week.

What Do Hoya Flowers Look and Smell Like?

Hoya flowers grow in a ball-shaped cluster or umbrel, similar to mophead hydrangeas. Each cluster may contain up to 40 individual flowers packed tightly together. The individual flowers look perfect as if molded from wax or porcelain, thus their common names. Flowers often sport a colored eye in the center of the corona. The flowers have a sweet smell, varying from vanilla to citrus.

How to Encourage More Blooms

To encourage more blooms, ensure the soil is well-draining, the plant has at least six hours of light, has moderately moist soil, and is protected against insects and disease. Also, keep the plant root bound, it encourages flower production.

Deadheading Hoya Flowers

Never deadhead hoya flowers. Cutting off the spurs, where the flowers bloom from, damages the flowering part of the plant, and it will not bloom again the following year.

Common Problems With Hoya Plants

Hoya plants are tropical plants, so mimicking their ideal conditions can be tricky. The most common problems arise from not getting their growing environment right.

Leaf Drop, Leaf Blackening, Stem Dieback

Overwatering can be one of the biggest problems, causing root rot. Also, not providing a warm enough environment can be equally problematic. Each of these problems can cause a plant to shed its leaves, leaf blackening, or stems to appear to die. Overwatering can also make leaves turn yellow and droop. You can rescue or save a dying plant by correcting the water, humidity, and temperature conditions.

Wilting

Overwatering can also cause wilting, but so can too much fertilizer, making the roots unable to absorb water. If your plant has excessive salts in the soil, flush it with water thoroughly. Withhold giving fertilizer; instead, after a month or two, try giving compost tea or compost top dressing.

Lanky, Straggly Growth

If your plant begins to look stringy, it's possible it does not have enough light and is looking for more. Plants stretch out in search of more light. Move your plant closer to more light or, if growing indoors, give your plant a fluorescent grow light.