Bloom Watch 2024

Bloom Watch 2024

Each year for one evening only, Tohono Chul opens its doors to visitors from all around the world to experience the mystery, majesty, and beauty of the Queen of the Night, the night-blooming cereus, Peniocereus greggii.

Because the mass blooming of the Queen of the Night is hard to predict, sometimes there are as little as 12 hours between the announcement of Bloom Night and Bloom Night itself.

Bloom Watch email updates are the best way to make sure you won’t miss this event! Click here to sign up.

Members Only

This year, Bloom Night is exclusively for Tohono Chul members. Your support helps preserve the Desert View Trail and our Peniocereus greggii collection while ensuring proper pollination.

Don’t miss out! Become a member today and experience this exclusive evening with the Queen of the Night.

Bloom Watch Diaries 2024

Follow the Queen’s progress with the Bloom Watch Diaries! The blog will be updated with weekly updates on her growth, reflections about the desert, and estimates about the Queen’s arrival.

Get Updates with the Bloom Watch Newsletter!

The Queen of the Night is here in abundance as Tohono Chul is home to the world’s largest collection. When the summer heat begins to build, the buds of the night-blooming cereus begin to appear. After a period of start-and-stop growth, the buds blossom in a mass blooming one night between the end of May and late July. Experience the magnificent Peniocereus greggii in its full glory; stroll luminaria illuminated trails leading to each plant; marvel at their gorgeous flowers; breathe in their intense and intoxicating scent.

Once you’ve entered your email address, click continue and then select the Bloom Watch email list.

Bloom Watch emails will update you on the progress of the blossoms right up to the day we announce Bloom Night.

Check out these videos of Bloom Night!

Timelapse footage provided by Arizona Daily Star

Timelapse footage provided by Stephen Buchmann

Bloom Night | Quick Tips & Info


  • Wear comfortable, closed-toed walking shoes and outdoor clothing.
  • Bring a flashlight and a water bottle
  • Bring a camera with a flash
  • Bloom Night is considered a special event and guest passes are not eligible to use.
  • Bloom Night is a Member Only event this year. Not a Member? Become one here or at Admissions on the night of the event!


  • The majority of flowers bloom the same evening usually between late May and Mid-July.
  • Tohono Chul has the largest private collection of Night Blooming Cereus in the world.
  • Researchers still don’t know how the flowers know when to bloom en masse.
  • Each year 1,500 to 2,500 people attend Bloom Night.
  • Flowers start opening at 6 pm and are in full bloom by 9 pm.

Queen of the Night Coloring Sheet

Courtesy of Adela Antoinette

Adela Antoinette has a beautiful publication in honor of Bloom Night: Cacti Oasis coloring book, and she has provided her Queen of the Night coloring page here just for us!

Cacti Oasis Coloring Book: Cacti & Succulents is a Sonoran desert-themed, illustrated coloring book filled with cacti & succulents.

“I want to share my love and passion with those who have just as much love for Sonoran botany as much as I do.” – Adela Antionette

Adela Antoinette (She/Her) is a published illustrator, designer, and makeup artist. As a southwest-born desert dweller, Antoinette’s work primarily centers on Sonoran Desert flora but fluctuates within botany through visiting different regions across the states. She specializes in various traditional mediums including her favorite, watercolor in which she has taught in workshops and classes at the Denali Education Center and The Drawing Studio. Her work has been displayed in various galleries in Arizona, Alaska, and California. Antoinette studied illustration and design at the University of Arizona, receiving her degree in Visual Communication. She is a Tucson, Arizona artist currently living in New York City.


It has a hallowed place in Tohono O’odham storytelling, has inspired folk songs, paintings, thousands of photographs, and even a perfume. The Night Blooming Cereus, Peniocereus greggi, the aptly nick-named “The Queen of the Night”, creates an elusive flower, blooming en masse only one night of the year. Opening slowly at dusk the beautiful palm-sized flower is wilted within a few hours of sunrise.

Tohono Chul, a non-profit botanical garden and nature preserve, on Tucson’s northwest side, has the largest private collection of Peniocereus greggi in the world. Native to Southwestern North America, the cactus looks like a bunch of dead sticks most of the year, only revealing its spectacular flower in the heat of the early Tucson summer.

Since the cactus cannot self-pollinate, the plants must bloom on the same evening to ensure pollination, usually by hawk moths. The more blooms that are open, the greater the chances of pollination. The true mystery of the Night Blooming Cereus is how the majority know when to bloom.

“We’ve been studying the NBC for over 20 years now and we still don’t know what triggers the bloom. The best we can figure is there is some type of chemical communication amongst the cacti” says Lee Mason, former Director of General Services for Tohono Chul.

Tohono Chul planted and cultivated many of the cacti, others grew naturally on the grounds creating an amazing collection. Thinking it was a shame that the gardens were closed while these rare flowers were blooming, it was decided to stay open late for a few volunteers and their friends. It’s since turned into an annual event with thousands of people attending each year.

And that’s no small feat considering Bloom Night cannot be called until between 12 pm and 4 pm the day of the bloom. “We usually have a pretty good indication within a few days of the bloom, but they’ve tricked us before so we wait until we’re absolutely positive to make the call”, says Mason.

Upon the official bloom call, Tohono Chul galvanizes its forces, contacting dozens of volunteers to help light the desert paths and organize tours, the media is contacted and local news crews descend upon the Park and the local populace changes its dinner plans to attend.

“It’s incredible how the entire community immediately reacts once Bloom night is called, “ says Marcia Ring, Tohono Chul’s former Marketing Manager, “This has truly become the quintessential summer event in Tucson, which, considering the uniqueness and beauty of the bloom, isn’t really surprising”.