The moonflower cactus, Selenicereus wittii, produces a stunning, snowy bloom once a year for only 12 hours. The cactus, native to the rainforests of Brazil, flowered for the first time in the United Kingdom at the Cambridge University Botanic Garden (CUBG) on February 20, captivating an audience of 400,000 people who live-streamed the bloom on YouTube and the CUBG webpage, reports Harry Baker for Live Science.
Despite belonging to the cactus family Cactaceae, the moonflower's stem looks like large flat leaves and snake themselves around host plants, such as trees. Moonflowers use this tactic to avoid the Amazon rainforest's seasonal flooding, the CUBG explains in a statement. Other examples of epiphytic plants are orchids and tillandsias, also known as air plants.
The moonflower found wrapped around a water chestnut tree at the CUBG was obtained in 2015 from the Bonn Botanic Garden in Germany, but bloomed for the first time this year, reports the BBC.
"In the case of this species, we are probably the only people to have captured time-lapse footage of it blooming," CUBG glasshouse supervisor Alex Summers told Live Science.
CUBG staff first noticed the rare cactus had sprouted a flower bud in November. During February, it increased in size, which meant that the flower was powering up to blossom.
"I noticed the flattened stems, or pads, which swirl around the trunk of our Water Chestnut had sent out a flower bud in late November – which was a lucky spot as it's almost 12 feet up in the air and could have so easily been missed! But it has only recently increased radically in size, which means a flowering is imminent," said Summers in a statement.
When the bud's growth spurt reached 7.9 inches, CUBG staff began livestreaming on February 9 in anticipation of its bloom. Livestreams continued for 11 days until the Amazonian cactus finally started bursting into a dizzying array of white-spiked petals on February 20 around 3 p.m. local time and lasted until 3 a.m., reports Live Science. The bloom's timing surprised the researchers at CUBG since, in the wild, the moonflower begins to bloom at sunset and ends at sunrise, but this flower started in the afternoon. Summers explained to Live Science that the lighting from all the webcams might have disrupted the flower's circadian rhythm, changing the blooming time to earlier than expected.
Viewers experienced full bloom two hours later at 5 p.m. local time and reached a diameter of six inches wide and 11 inches long, the BBC reports. While blooming, the Amazonian cactus releases a unique sweet scent similar to honeysuckles and gardenias, but that scent is short-lived, Live Science reports. The smell turns rancid as the scent chemicals break down and turns the flower's sweet scent into something reminiscent of a public bathroom, Summers explained to Live Science. In the wild, moonflowers use this scent to attract two hawkmoth species with long proboscises, or tongues, that will pollinate the flower, reports IFLS.
For CUBG's moonflower cactus, Summers quickly hand-pollinated the plant using a paintbrush in hopes that it will produce seeds that can be shared with other botanic gardens. In cultivation, the moonflower cactus is only found in 13 botanical gardens worldwide, according to the CUBG.
"We've been totally overwhelmed by the interest our flower has created. As scientists, botanists and horticulturalists here at the Garden, we are all fascinated by plants, but it's been so heartwarming to see how our moonflower has captured the hearts and interest of so many people across the globe," commented CUBG director Beverly Glover in a statement.