Hoyas and their close cousins Dischidia are old world tropical plants found mainly in tropical Asia and many of the tropical islands. This group consist of mostly vine like plants that normally grow epiphytically usually growing on larger trees. Both Hoyas and Dischidia can have very unusual foliage usually small colorful to odd shaped leaves held together on a small vine. I find for me they tend to grow in the hottest section of my greenhouses near the roof where it is very hot and though watered regularly drys out quickly. Many can also be grown as indoor plants easily.