Hoya plants are tropical vining members of the milkweed family that make exceptionally beautiful house plants. The leaves and fragrant flowers are covered with a waxy, semi-glossy substance, hence the name "wax plant". Hoyas tend to be a little fussy about water and lighting. However, these plants are undemanding and require very little in the way of maintenance as long as their basic needs are met.
Plant your hoya in a rich, very well-draining soil. Mix your own by combining equal parts peat and loam with ½ part each vermiculite and perlite. Add 1 ½ tablespoons of bone meal per gallon of potting mix.
Place your hoya plant in the brightest spot in your home, about 3-4 feet away from a south-facing window if possible. These plants love direct morning sun, but won't tolerate hot afternoon summer sun. If only indoor lighting is available, provide the plant with at least 8 to 10 hours each day.
Provide a daytime high temperature of about 72 degrees F, with 60 F overnight being best during the growing season. Keep the hoya slightly cooler in the winter to encourage spring bloom development. A temperature range of between 55 and 60 F is ideal.
Set the plant on some pebbles in a tray of water and mist it up to several times daily to increase humidity throughout the year.
Water the hoya by drenching the soil. Let it dry out to ½ inch below the surface before watering again during the growing season. Reduce water frequency during the fall and winter, allowing the soil to dry out almost completely between waterings. Spring bloom production will be enhanced by drier winter conditions.
Feed the hoya plant a 5-10-5 fertilizer once about every 6 to 8 weeks throughout the growing season. Follow the packaging instructions carefully.
Prune only dead or damaged stems from your hoya plant. Do not deadhead the hoya or prune off stems that have flowered until the plant has completed its seasonal blooming cycle. New buds will grow from the old flower stems. The plant may very well bloom two or three more times during the season. If the vines are becoming quite long or if you prefer a compact appearance, loosely tie the stems to a fan-shaped trellis.
Remove the hoya plant from its pot in the spring before blooming begins to check the rootball. If you can only see a few roots, it doesn't need to be repotted this year. If you see an abundance of root hairs, step the plant up a pot size. Hoyas prefer to be a bit potbound, and often won't bloom for the first year or two until a substantial root system has developed.