Given the err .. exotic nature of your request, I'd have to probably guess that the Botanical Gardens is the best place for you to start your reference. Ask the curator if he/she has an idea ( and my bets are they will )
Address: Albany Road, Central, Hong Kong
Telephone: (852) 2530 0154
Fax: (852) 2537 1207
E-mail: shchik@lcsd.gov.hk
I know what is prickly pears. I don't eat them. I used to feed my reptiles on prickly pears. Excellent food for them. But in HK i can't find any for sale......... That's why i asked that..