Thousands watch live stream as rare cactus starts to bloom in UK

Thousands of people around the world have been tuning into a live stream of a rare cactus as it prepares to bloom – thought to be the first such event in the UK.

Now, horticulturists say the event has begun, and will be over by sunrise on Sunday.

The moonflower, which is growing in Cambridge University’s Botanic Garden (CUBG), will bloom for just 12 hours before the flower dies. The live stream has been running for several days, and has been viewed more than 120,000 times.

A caption on the live stream on Saturday said: “We think that tonight is the night!”, but the moonflower now appears to be close to full bloom.

In the early hours of Saturday morning, the flower was still a tightly curled bud, but it has unfurled over the course of the day to reveal a display of white petals.

The Amazonian plant Selenicereus wittii was expected to bloom at about 9pm, producing a large white flower that lasts from sunset to sunrise. But in comments on the live stream, the team said the blooming was happening “a bit earlier than expected”, and that they were “so excited”.

The team said they would bring forward a planned live Q&A on Facebook from 9.30pm to “teatime”.

The moonflower plant spirals around tree trunks, and the coveted flower is around 12ft (3.65 metres) in the air. This plant is believed to be the only specimen in the UK, and worldwide it is listed in only 13 botanic gardens.

The coveted flower produces a sweet-smelling scent that turns “rancid” after just two hours, as the plant begins to die. The plant is only found the high waterline of the floodplain rainforests of the Amazon basin, and its flowers reach 27cm in length.

However, there has been some confusion over the rarity of the flower, with members of the public reportedly claiming to have their own versions of the plant and sending photos to the botanic gardens. The team at CUBG published an article clarifying that “moonflower” was a name used for many different species of plant.

“It is likely that most people may have Epiphyllum oxypetalum. A common epiphytic cactus species in cultivation. This is not in the same genus as the moonflower we have growing here, which is Selenicereus wittii,” said Alex Summer, who is responsible for growing and nurturing the plant at CUBG.

“Plant growers in a domestic setting will not have Selenicereus wittii, as this is extremely uncommon in cultivation and only ever likely to be found inbotanic gardens or in the Amazon rainforest.”

However, the team said they had “loved receiving the images of your Epiphyllum oxypetalum blooms”, sharing a selection “the stunning examples of homegrown moonflowers sent to us by the public”.

Last week, Summer said he was “so excited to see and share this most unusual flowering”.

“It’s very rare to have this plant in our collection and we believe this is the first time the moonflower has flowered in the UK,” he said.