Hoyas seem to scream tropical; winding through trees with their heady-scented flowers. Luckily for those who live in cooler climates there is a huge selection of hoya that will tolerate those chilly temps. When talking about cool growing hoya this is referring to species that can tolerate ongoing periods of temperatures below 10°C. 

Its widely known that H. carnosa and its cultivars are extremely tolerant to a variety of conditions; one could almost call it the Monstera deliciosa of the Hoya world, considering how widely cultivated it is. Well, my friends, along with H. carnosa there is a huge list of species and cultivars that are extremely cold tolerant as well as a large portion of intermediate growers that can tolerate quite a lot. Some that are all extremely tolerant of prolonged periods of cold include, as long as they are protected from the elements:

• H. bella

• H. compacta

• H. fungii

• H. kerrii

• H. kanyakumariana

• H. lacunosa

• H. linearis

• H. motoskei

• H. obovata

• H. pauciflora

• H. polyneura

• H. shepherdii

• H. pubicalyx

• H. serpens

• H. sp ‘pink’

• H. cv. ‘Mathilde’

• H. cv. ‘Chouke’

• H. leoycendrewsiana

• H. albiflora

Growing them sheltered from frost, extreme cold wind and excessive rain is crucial to the longevity of these cold tolerant species.

Along with the cold growers there is also a large selection of intermediate growers that can tolerate cooler periods, ensuring they are protected from extreme weather. Some might experience slowed growth and slight foliage discolouration; however, they will continue to grow. Through trials and tribulations, we have experienced and noted the extent these species can tolerate. Surprisingly, that includes a large selection of the supposed intermediate/warm growers. These include species such as; 

• H. heuschkeliana

• H. bilobata

• H. finlaysonii

• H. calistophylla

• H. erythrina

• H. davidcumngii

• H. dischorensis

• H. coriacea

• H. cinnamomipholia

• H. caudata ‘Sumatra’

• H. deykeae

• H. clandestina

• H. macrophylla

• H. fischeriana

• H. litoralis

• H. macgillvrayii

• H. meliflua

• H. archboldiana

• H. elliptica

• H. wibergiae

• H. vitellina

• Nearly all of the H. australis varieties

 Experimenting with your Hoya is the only true way to understand which species work for your conditions. All plants are different, some are simply stronger than others. Therefore, just because I can grow a specific species outdoors doesn’t necessarily mean the specimen you own will survive in the same conditions. Remember that the best time to experiment is during Spring and Autumn, as long as the chance of frosts are low. You will never know unless you try, and you might be pleasantly surprised with which ones you find can tolerate some of those harsher outdoor conditions.