They grow good in "African Violet medium with added perlite which is kept moist. Hold water during the winter months. Misting is recommended but not when in bloom. Fertilize during the spring with a liquid food every four weeks, three or four times during the growing season. Do not fertilize during winter as the plants go semi-dormant. Leave flower spurs on plant as it will again flower on the same spurs. Do not transplant too often as hoyas like to be a bit root bound. Maintain the atmosphere around your hoyas humid and bright. 1
Hoyas are propagated by stem cuttings which will take an average of two years to bloom. An easier way of propagation is by layering where the stem is pined down at the joint in a moist rooting medium. Cut and pot the new plant when roots have formed.1
Hoyas were named after Thomas Hoym, Gardener to the Duke of Northumberland because he was the first to bring this superb house plant into prominence.1
Hoyas has been classified in the asclepias (milkweed) family.1
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1 http://plantcaretoday.com/how-to-care-for-grow-and-bloom-hoya-plants.html