12 Hoya Plant Problems and How to Fix Them (Hoya Problems and their Remedies)

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Hoya Plant problems include yellow leaves, brown leaves, shrivelled leaves, flowerbud drop, lack of blooms, pests and diseases among others. Keep reading for more on these problems and how to fix them.

Hoya Plants are popular, vining, flowering plants which bear spectacular clusters of star-shaped, fragrant flowers and fleshy leaves.

Hoya are referred to by many names like Waxplant, Waxvine, Waxflower, Porcelainflower or simply Hoya. The Hoya genus was named by botanist Robert Brown, in honour of his friend, botanist Thomas Hoy.

There are over 500 species of Hoya Plants which belong to the family Apocynaceae (Dogbane) family and are native to the tropical regions of Asia with many species also found in Australia. Here are 11 Hoya Plants with names and pictures.

Care for Hoya Plant

Care for Hoya Plants is easy if the don'ts are observed. Some of these are don't disturb the plant once the buds appear as change in light intensity may cause them to drop.

Don't remove the dead flowers as new flowerbuds will form in the spurs. Don't repot until it is unavoidable as being root-bound encourages flowering. It benefits from loose potting medium that allows some air to get to the roots.

Generally, Hoyas thrive in bright light with with 4-6 hours of direct sunshine, average warmth of 16-26⁰C, moderate humidity of 50-55% and moderately moist, rich, well-drained, hoya potting soil coupled with monthly feeding during the growing season. Read more on how to grow, care and propagate Wax Plant (Hoya carnosa).

If the right growing conditions are not provided, Hoya Plants are bound to present some problems. Keep reading for more on these Hoya growing problems and their solutions.

12 Common Hoya Growing Problems and How to Solve Them

1. Pests

Hoya is prone to mealy bugs, scales and spider mites. Regularly check underneath the leaves for these pests and isolate the affected plant to prevent spread to the other plants.

Treat the affected plant with appropriate products like neem oil or insecticidal soap to get rid of the pests. Ensure to follow the manufacturer's recommendations.

2. Diseases

Hoya Plant is prone to two plant diseases. One common disease in Hoya is root-rot disease which is enhanced by soggy soil and is characterized by soft wrinkled, smelly leaves.

Carefully, slip the plant out of its pot and inspect the roots. Brown mushy roots indicate root-rot. Cut the brown-black roots and treat the healthy roots with a fungicidal solution.

Repot the plant in fresh soil and keep it dry for some time before resuming watering. Read more on how to treat root-rot disease in houseplants.

Always ensure that the pot has a drainage hole and the soil is free-draining to prevent the soil from getting soggy. Also, reduce watering in the cold season as growth is minimal at this time.

The second common disease in Hoya Plant is leaf spot disease which is prevalent in warm, damp conditions and is characterized by small, dark spots on the leaves, stems and flowers.

Improve ventilation and ensure that there is good air circulation at all times. Avoid wetting the foliage and water from the bottom instead to keep the foliage dry.

3. Yellow leaves

Yellow leaves in a Hoya Plant are due to three possible reasons. One possible reason is overwatering or soggy soil caused by poor soil drainage.

Hoya Plant cannot tolerate soggy soil. Ensure that the pot has a drainage hole and that the soil is free-draining to prevent it from getting soggy.

The second possible reason for yellow leaves in Hoya Plant is too little light as it grows best in bright light with 4-6 hours of morning or late afternoon direct sunlight but do not expose it to hot direct sunshine as it can scorch the leaves.

Position the plant next to a bright window where it can receive bright light. if the natural lighting is not adequate, consider installing a grow light to supplement it. Take a look at these full spectrum grow lights on Amazon.

The third possible reason for yellow leaves in a Hoya Plant is underfeeding. Feed Hoya Plant with a phosphorous-rich, water-soluble fertilizer every 4 weeks during the growing season.

Do not feed in the cold season as growth is minimal at this time and feeding at this time can cause fertilizer burn and eventual death of the plant.

4. Dry Shrivelled (wrinkled) leaves

Dry shriveled leaves in Hoya Plant are caused by three possible reasons. One possible reason is underwatering which results in too little moisture in the soil.

Hoya requires that the soil be maintained moderately moist through out the growing season and slightly moist in the cold season. Never allow the soil to dry out completely.

The second possible reason for dry shriveled leaves in a Hoya Plant is compacted soil. Ensure that the soil for Hoya is loose, fertile and well-drained.

Use a quality Hoya potting mix to pot the plant and repot the plant if the soil is broken down, usually every 2-3 years. Do not repot a plant that is in flower as it can shorten the flowering period due to repotting shock.

5. Flowerbud drop

Flowerbuds drop in Hoya Plant is due to four possible causes. One possible cause is incorrect watering; either overwatering or underwatering.

Keep the soil moderately moist during the growing season and slightly moist in the cold season but never allow the soil to get soggy neither completely dry.

Always ensure that the pot has a drainage hole and that the soil is free-draining to prevent it from getting soggy.

The second possible cause of dropping flowerbuds in Hoya is sudden changes in the light conditions.

Do not move a Hoya Plant that is in flower; it does not like changes in light conditions while in flower and it responds with flowerbud drop.

The third possible cause of flowerbuds drop in Hoya Plant is sudden change in temperature. Keep the plant away from drafts to avoid sudden changes in the temperature and maintain a constant average warmth of 16-26⁰C.

The fourth possible cause of dropping flowerbuds in Hoya is dry air (low humidity) especially where the temperatures are very high.

To increase humidity, set the pot on a wet pebble tray, grow the plant in a brightly lit bathroom and other moist areas in the home or use a cool mist humidifier.

6. Brown leaves

Brown leaves in Hoya Plants are caused by two possible causes. One possible cause is incorrect watering; either underwatering or overwatering.

Water Hoya thoroughly during the growing season while allowing the top 2-3 inches of soil to dry out between waterings to keep the soil moderately moist.

Decrease watering in the cold period and keep the soil slightly moist but never allow the soil ball to dry out completely.

Also, ascertain that the pot has a drainage hole and that the soil drains easily to prevent it from getting soggy.

The second possible cause of brown leaves in Hoya Plants is too high temperature. Keep the plant away from hot drafts to maintain an average room temperature.

Hoya prefers an average warmth of 16-26⁰C during the growing season. Keep it away from cold and hot drafts like windy doors and windows, hot surfaces, air conditioning units among others as they cause sudden flactuations in temperature.

7. Black leaf spots

Black leaf spots on the undersides in Hoya Plant are an indication of overwatering or soggy soil. These are a sign of oedema whereby the plant cells take up too much water and eventually burst open leaving these black spots and corresponding white pits on the upper surface.

Take care not to overwater Hoya. Reduce watering and maintain the soil moderately moist and ensure that the pot has a drainage hole to prevent the soil from getting soggy.

8. Sudden leaf drop

Sudden leaf drop in Hoya Plant is due to four possible causes. One possible cause is improper watering; either underwatering or overwatering.

Maintain the soil moderately moist during the growing season and slightly moist in the cold season but do not let the soil get soggy or completely dry.

Use a pot that has a drainage hole and soil that is loose, free-draining to prevent it from holding excess water.

The second possible cause of sudden leaf drop In Hoya is extreme temperatures; either too high or too low due to hot or cold drafts.

Keep the plant away from drafts to maintain an average warmth as Hoya grows best in average warmth in the range of 16-26⁰C.

The third possible cause of sudden leaf drop In Hoya is too little light as Hoya prefers bright light with at least 4-6 hours of morning or late afternoon direct sunlight.

Place the plant where it will receive bright light with some morning or late afternoon sunshine or instal a grow light where the natural lighting is not sufficient.

The fourth possible cause of sudden leaf drop In Hoya is incorrect feeding; either underfeeding or overfeeding both of which affect the proper functioning of the plant systems.

Take care and feed Hoya Plant every 3-4 weeks during the growing season with a water-soluble, fertilizer but do not feed during the cold season as it can result in fertilizer burn and death of the plant.

9. Leggy growth

Leggy growth with wide spaces between leaf nodes coupled with undersized leaves in Hoya Plant are due to too little light or inadequate light.

Make sure that the Hoya Plant receives bright light with at least 4-6 hours of morning or late afternoon direct sunlight. Where the natural lighting is not enough, use a grow light to supplement it.

10. Lack of blooms

Lack of blooms in Hoya Plant is due to two possible reasons. One possible reason is too little light or inadequate light.

Position the plant in a brighter spot where it will receive bright light away from hot direct sunlight or instal a grow light if the natural lighting is inadequate.

The second possible reason for lack of blooms in Hoya Plant is feeding it with a nitrogen-rich fertilizer which promotes foliage growth at the expense of flowers.

Feed Hoya with a phosphorous-rich, water-soluble fertilizer every 3-4 weeks during the growing season but do not feed during the cold season as it can lead to fertilizer burn and death of the plant.

11. Curling leaves

Curling leaves in Hoya Plant are caused by sap sucking pests like mealy bugs, scales and spider Mites. These pests attack the soft growing parts from where they suck the plant sap causing dehydration and distortion of the parts of the plant.

Regularly inspect the plant for these pests and take timely pest control measures as a heavy infestation can lead to the death of the plant.

12. Toxicity

Hoya Plants produce a milky white sap which contains latex. The latex is considered to be toxic to humans and pets. Always wear gloves when handling these plants and keep them away from the reach of children and pets.