Bloom Watch #1 | Caring for the Queens
May 13, 2026Stewarding the Queens
Temperatures are on the rise again, waking the queens from their long winter sleep. The first signs are hard to read, with tiny wart-like bumps appearing on the stems of what the Tohono O’odham call Ho’ok wa:ho (witches tongs). At first, it can be hard to tell the buds from new branches, but soon the coarse white hairs telltale swelling of the buds becomes obvious.
The gardens team hasn’t been idle while the queens have been in repose. Over the last year, we have planted dozens of new Peniocereus greggii specimens throughout the gardens, building our collection back up after losses induced by years of drought and above-average heat. The new plants are carefully placed under nurse trees such as mesquite (Neltuma velutina) and foothill palo verde (Parkinsonia microphylla) and usually provided with shade cloth and metal cages to keep off the sun and hungry javelina, who will uproot the tubers to gorge themselves on the water and nutrients stored within.
We have added shade cloth to nearly all our established plants as well, and have seen a notable increase in biomass and health, as the plants shake off the damage that has caused them to shed branches and retreat underground. It’s clear that the queens are a proverbial canary in the coal mine, warning us about the impacts of global warming on our beloved flora.
Aside from caring for the physical needs of the plants, our living collections team has been going through 33 years of data about the queens, scattered in notebooks dating back to 1993. All of this information is being digitized and compiled to help us better understand the rhythms and cycles of the queens. This is perhaps the longest-term data set collected about the flowering of these plants, and our goal is to build off this existing data to assist researchers in learning about this enigmatic and incredible desert plant.
The queens follow a similar pattern every year, sprouting their developing flowers in the spring until they’ve grown into teardrop-shaped buds that slowly stretch, millimeter by millimeter, until they pause as the heat and drought of the arid foresummer becomes oppressive. Then they enter what we call their “stall phase,” waiting for conditions to become more humid, before putting on a sudden spurt of growth that will see the buds rapidly elongate, swelling near the top like a furled-up tulip.
Each queen has its own personality; we know who we can rely on to flower every year, and through diligent measuring, we are learning that certain individuals consistently produce smaller or larger buds before flowering. We know that all the plants will bloom in the same 4-12 day period. The question is always, when?
For now, gardener Shauna Smith is heading out to the trail weekly, watering the queens to tide them over until monsoon clouds start to form around the margins of the azure summer sky. While she is on the trail, she identifies and notes which plants are budding and meticulously measures the length and width of each bud, watching for signs of the approaching bloom.
As always, we will be closely observing our queens and reporting out our bloom forecast. Keep an eye on the bloom watch updates and be sure not to miss our nightbloom event, a one-of-a-kind desert experience at Tohono Chul.
– Written by Jack Dash, Tohono Chul Gardens & Facilities Manager
Members Exclusive
Bloom Night is an exclusive members-only event. Your support helps preserve the Desert View Trail and our Peniocereus greggii collection while we work to ensure the proper pollination and delicate nature of these special plants.
Don’t miss out—become a member today and unlock a year of perks and benefits at Tohono Chul, including early access to plant sales, discounts, free daily admission, reciprocal admissions at other public gardens, and much more.
Get Updates with the Bloom Watch Newsletter or on Social Media!
The best way to ensure you don’t miss Bloom Night is by subscribing to Bloom Watch email updates. Bloom Watch emails will inform you of the progress of the blossoms right up to the day we announce Bloom Night. Sign up today!
We also share Bloom Watch updates on social media—follow along on Instagram or Facebook for the latest updates!
Once you’ve entered your email address, click continue and then select the Bloom Watch email list from the drop-down menu.
