There are many different plant groups that share the common name ‘Moonflower’, but not all are the same.
You may have a Moonflower at home. Although they may share some similarities in appearance to the one here at the Botanic Gardden, it is highly unlikely it is the same plant.
Senior Horticulturist, Kathryn Bray explains:
‘It is likely that most people may have Epiphyllum oxypetalum (Queen of the Night), which is a an epiphytic cactus species common in cultivation. This is not in the same genus as the Moonflower we have growing here, which is Strophocactus wittii.
Plant growers in a domestic setting will not have Strophocactus wittii, which is is extremely uncommon in UK cultivation, most likely to be found exclusively in Botanic Gardens or in its native range of the Amazon Rainforest.’
What's the difference between S. wittii and the common E. oxypetalum?
Three to four clones of S. wittii are recorded in Europe across the Botanic Garden network. It is extremely unlikely that it has been introduced into cultivation outside of this, considering conservation protocols and laws involving wild plant species.
S. wittii and E. oxypetalum have a few key differences:
Firstly, S. wittii has spines along the pad margins, whereas E. oxypetalum lacks spines, which are actually modified leaves.
The pads are also different in shape – Epiphyllum species will have much longer, elongated pads, which can be quite branched.
Both species can be grown epiphytically (on a host) and will produce roots along their midribs. S. wittii is grown at CUBG on Pachira aquatica, where it is given a helping hand to support itself with some horticultural elastic.
From a taxonomic perspective, the long flower shoot of Epiphyllum is naked/not covered by scales, whereas the pericarpels (flower shoots) in Strophocactus have hairs or spines. These are quite visible on the flower bud at CUBG, and make it look quite fluffy!
Below: Our rare (in cultivation) Strophocactus wittii Moonflower in flower 2021
Below: The more common Epiphyllum oxypetalum Moonflower.
According to the Botanic Gardens Conservation International (BGCI), the species that we are growing can be found only in 16 botanic gardens globally. To put this in to perspective, this makes it even rarer in cultivation than the Titan arum (otherwise known as the Corpse Flower) which bloomed at here in 2017. Read more about this fantastic flowering here.