Species in Hoya

Hoya carnosa is an evergreen epiphytic vine native to southern China, Taiwan, southern Japan and parts of mainland Southeast Asia. Its stems reach up to 6 m and climb trees and rocks by aerial roots. The fleshy, glossy leaves are ovate to elliptic, 3.5 to 13 cm long, and the species name refers to this succulent texture. Rounded clusters of about 30 star-shaped, waxy flowers 1.5 to 2 cm across are produced from persistent spurs; they are white to pale pink with a pink to red center and sweetly fragrant. Many cultivars with variegated or contorted leaves are grown as houseplants. The ASPCA lists it as non-toxic to cats and dogs.

Hoya kerrii is an evergreen epiphytic climber in the dogbane family (Apocynaceae), native to Indochina and western Malesia, from Thailand to Java. Its wiry stems climb trees with aerial roots and reach about 4 m, and they contain white latex. The thick, succulent, hairless leaves are broadly ovate with a deeply notched tip, giving them a heart shape; they are up to about 9 cm long and 8 cm wide, with 5 or 6 lateral veins. Rounded umbels about 5 cm across hold 10 to 25 cream to white star-shaped flowers 7 to 8 mm wide with a dark brown to pinkish-brown corona. The flowers are fragrant at night and secrete reddish-brown nectar that can stain surfaces. The species was described in 1911 from plants collected on Doi Suthep near Chiang Mai, Thailand. Single rooted leaves are often sold as gifts, but a leaf without a piece of stem rarely grows into a vine. It is generally listed as non-toxic to pets, though the sap may irritate sensitive skin.