This Arizona cactus blooms for 1 night. Here's when to see the rare Queen of the Night (2024)

Cactuses sure give Arizonans a lot to talk about. From towering Saguarosthat are not what they look like, to acactus looking like a couple kissing. But every summer, the queen of cactuses makes an appearance to showcase its stunning flowers thatbloom en mass for only one night every year.

On Saturday, June 29, the majority of these flowers were expected to bloom, offering those who catch the event one of nature's most unique experiences.

Here's what to know about the Bloom Night event in 2024 and about the Queen of the Night, the Arizona-native flower that blooms for only one night each summer.

Tips to make the most out of Bloom Night 2024

Tohono Chul gave the following advice to people planning to attend Bloom Night this year:

• Bring a flashlight and a refillable water bottle.
• Wear closed-toe walking shoes and comfortable outdoor clothing.
• Be aware of your surroundings and watch your step; the Desert View Trail is home to wildlife such as rattlesnakes, tarantulas, lizards, insects and more.
• Bring your membership card if you are a member.
• Guest Passes are not eligible for this special event.
• For photography, remember to bring a camera with a flash or external lighting and be mindful not to block the view of other members when capturing photos of the Queen.

Kissing cactus: This Arizona cactus is getting noticed for its odd shape

When does the Queen of the Night bloom?

This cactus, scientifically known as peniocereus greggii, can start to bloom from May to late July. Brian Rasmussen, curator at the University of Arizona campus arboretum, said a few individual flowers might bloom at different times during the summer months, but there's a single night in which the vast majority of them bloom in mass.

Matt Johnson, manager and curator of the Desert Legume Program at the University of Arizona, said no one knows exactly why this synchronized phenomenon happens, and it's extremely hard to predict when that bloom night will occur each year.

"It's very hard to tell when it will happen," Rasmussen said. "You just have to watch the buds as they grow bigger, that's really the only way you could tell. But you don't know when a blooming sequence happens until it, they start opening up."

What time does the Queen of the Night bloom?

The flowers usually begin to bloom after sunset around 8 p.m., reach full opening by midnight, and close by 9 a.m. the next morning. Each flower can be from 4 to 6 inches in diameter.

"All the plants in the area will bloom in the same night all together, and then the flowers close up in the morning," Rasmussen said. "Say the plant has 10 buds on it, probably 8 of them would bloom on that night. It's very captivating, it's an amazing plant."

Why does it bloom for a single night?

Just like a queen, this flower is beautifully tactical.

According to Raul Puente with Desert Botanical Garden, the Queen of the Night is pollinated by a moth, which is active at night. To attract the moth, the flower uses a few strategies.

When the flower is blooming, it releases a sweet scent that, according to Puentes, is perceivable to humans, which means the fragrance is quite strong for the much more scent-sensitive moths to smell from afar.

By blooming en mass, the plant increases its chances of being pollinated since it has more buds open at once and by producing an even more intense fragrance altogether.

What does the Queen of the Night look like?

For most of the year, this unusual cactus looks like dead sticks with a jumble of gray and purplish stems. But every summer for the blooming event, the queen chooses a white gown so she can reflect moonlight off her petals and make it easier for pollinators to find her.

"It's so uncactus-like in its appearance. Most people would not think it very attractive, it's not symmetrical like some other cacti are," Johnson said. "But then it has this spectacular flower, which is certainly the largest and showiest flower of any cactus native to Arizona."

The flower closes up shortly after the first of the sun's rays hit in the morning. Puente said this could be because, being such a large flower, the plant uses quite a bit of energy for the opening and can lose a lot of water when it blooms. By blooming at night, the plant also avoids water evaporation during sunlight hours.

Where can you see the Queen of the Night bloom?

According to Puente, this plant is pretty much scattered across the desert and is very hard to find because it typically grows under nurse trees and tends to camouflage as a bunch of wispy, dry sticks amid shrub branches. It is more common around washes, but your best bet is to look out for the blooming event every year, Puente said.

"It's very hard to spot them in the wild," Rasmussen said. "The one night of the year when most of all the flowers in an area open up is typically the only way you can see it."

Tohono Chul Botanical Garden, located at 7366 N Paseo Del Norte in Tucson, has the world's largest collection of the Queen of the Night and hosts an event every summer so people can see their mass blooming.

Because it is hard to predict, sometimes the announcement is given roughly 12 hours in advance. To be notified, you can sign up to the Garden'sBloom Watch newsletter.

Rasmussen said people can also find them at the university's arboretum at the Krutch Garden, next to Old Main and at the Desert Plant Conservatory on top of the 6th Street garage.

The Desert Botanical Garden also has a collection planted in ports near the trails so people can see them easily when they start blooming. Two of them were expected to bloom later this week, Puente said.