Tropicals & Tender Perennials: HOYA AUSTRALIS- a brief history, 1 by markroy68

markroy68 wrote:
TRIVIA- Hoya australis can be toxic to cattle and certain other livestock if consumed in large quantities. According to Dr. Ross McKenzie in his 1993 paper "Australian Native Poisonous Plants", "(Hoya australis) growing in the softwood scrubs of Queensland has been used as drought fodder for cattle. To much will damage spinal function and the cattle will collapse and may die". I have found no reports of toxicity to humans or household pets.
There are many traditional remedies involving Hoya australis used by Pacific Islanders. In Fiji it is (was) used to treat swollen testicles and hemorrhoids. In Tonga and Samoa it was used to combat inflammation and convulsions.
Hoya australis uses a procedure known as Crassulacean Acid Metabolism (or CAM). In this process the plant closes its stomata (pores) during the day to reduce the water loss which occurs during transpiration. It opens its stomata at night to take in CO2 and release oxygen. Note- this dosen't mean that australis should be watered at night- it will take in water when it is available, and breathe on it's own schedule. The diagram is my own.