We are expecting another flowering of the Moonflower cactus plant Strophocactus wittii (formerly Selenicereus wittii).
It is likely this will be at night, possibly some time over the next week and we have set up a webcam live feed, so people can follow it if they’d like to! [Edit 22.03.23 – the livestream has now been taken down as the flowering took place 18.03.23, but you can watch the timelapse video of the flowering.]
The first time it flowered was in February 2021 – which was the first ever flowering of this plant in the UK. This captured the attention of over 500,000 people during lockdown.
This beautiful flower, located in CUBG’s Tropics House, usually opens at night and flowers for just one night! However, in 2021 it surprised us by flowering in the afternoon. Our Glasshouse team are keeping a close eye on this one – they are expecting it to flower in the next week and at night, so we have set up a webcam so people can follow its progress.
Kathryn Bray, Senior Horticulturist at CUBG says:
“We’re measuring the bud daily. When this plant flowered in 2021, the bud was 26cm in length. Although this one is significantly smaller, we are anticipating flowering imminently as the bud is swelling and the pedicel (flower stalk) is beginning to lower, which is a sign it is getting ready to flower.”
“We first noticed the buds developing about 4 months ago and are excited now to see it flower.” We were delighted to see several buds forming over the last year, including one that caught us by surprise last weekend as it flowered when the bud was much shorter than expected. So we’re determined not to be caught out by this flower and to capture it on camera for everyone to enjoy.”
While the Moonflower isn’t rare in the wild, it is rare in cultivation. This species of Strophocactus is grown in just 16 botanic gardens worldwide. CUBG was able to share material with RBG Kew in 2022, so this plant is one of two clones in the UK. Although it is not as rare as some of our other glasshouse flora, such as the Tahina spectabilis (Self Destructive Palm), or Rothmannia annae (which is Critically Endangered in its native Seychelles), the Moonflower demonstrates how plants can thrive outside their native ranges and the role botanic gardens can play in ex-situ conservation.
Kathryn is also keen to point out that although the common name of this flower is the Moonflower, it is not to be confused with other flowering cacti which hold the same common name.
“The name Moonflower is given to a lot of cacti which people often have flowering at home. This does not mean though they are the same plant! Confusion like this is why we always use the Latin name for the plant, not the common name. This plant – Strophocactus wittii – is definitely very rare in the UK and in botanic gardens in general, outside its native habitat in the Amazon, so it’s important to always go by the Latin name.”
Strophocactus wittii is a fascinating and enigmatic plant for many reasons but one thing Kathryn is looking forward to is experiencing its scent. Just before the flower opens, it is known to give off a strong perfume. This is to attract pollinators in the wild. It is believed to be pollinated exclusively by two species of night flying hawkmoth. Both of these have incredibly long proboscises (tongues), which collect nectar produced by the flower. In the act of collecting this nectar, the flower is pollinated.
The team were able to collect and store pollen from last weekend’s flower and will use this to hand pollinate this new flower. They will use a paint brush to delicately brush this against the stigma, together with pollen from the current flower. Epiphytic cacti (plants which rely on another plant structure to grow on), are frequently self-incompatible, so although successful pollination is unlikely, Kathryn says she is excited to give it a go!
Please note: The Garden will remain closed to the public outside of normal opening hours , but keen Moonflower enthusiasts can check its progress via the livestream webcam. If the Moonflower surprises us with an afternoon flowering as in 2021, you may be able to come and see it when we are open!