The iconic saguaro thrives in the desert heat — for some, the cactus is practically synonymous with our state. Yet the biology of the saguaro is still a relatively new field of study.
And in recent years, scientists have started taking a closer look at saguaro cactus blossoms — small flowers that grow on the surface of the cactus. What can we learn from these vibrant blooms — and why are they so difficult to monitor?
High Country News recently explored these questions in a piece called “Counting Flowers to Read the Saguaro’s Future,” and The Show spoke with the author, Shi En Kim, about what makes the flowers so captivating.
Full conversation
SHI EN KIM: They honestly remind me of a fried egg because they have a yellow heart and pearly white petals, they’re really big, they’re like medallion size and they usually bloom all around the crown of the saguaro and deck the tips of the limbs of the cactus.
SAM DINGMAN: Wow, that’s a beautiful description.
KIM: Thank you.
DINGMAN: So, one of the other things that’s interesting about these flowers, right, is that they bloom pretty well into the saguaro’s life cycle, correct?
KIM: Yes, actually, they only start blooming when a saguaro is about 35 years old, which is quite late, but maybe not so late considering the whole lifespan of the saguaro. The cactus can live up to 200 years old.
DINGMAN: OK, so if I’m not mistaken, one of the reasons that scientists are looking more closely at saguaro flowers recently is because about what, like 15 years ago or so, they started to disappear.
KIM: It’s a bit of a complex picture. The scientists who started looking into the flower flowering patterns were just simply curious about them and no one had tracked these flowers before, so it’s easy to assume that they’re either declining or erupting more than usual, but someone needed to actually keep track of these flowers, year to year basically.
DINGMAN: Oh, interesting, I see. So what … if they had not previously been looked at very closely, the, the saguaro flowers, what made scientists start to get Interested in them?
KIM: Simply because they’re cool looking, anyone who goes into the desert can’t miss, so and it’s easy to start asking questions about, about these flowers.
When I talked to one source who worked for the National Park Service at one point as a ranger and he told me, the visitors would always have questions about the flowers when they visited in April, May, and these are just basic questions like, oh, how many flowers bloom on the cactus, what are they for? And for many of those questions, especially when it comes to count, at first the scientists had no answer for.
And it sounds like such a basic question that really and that really triggered research into this, this topic. But then, the more researchers are studying these flowers, the more they realize, even after 15 years, scientists still don’t have many of the answers to these questions.
DINGMAN: As scientists have started to look more closely at flowers, they seem to contain a larger story about the ecosystem of the desert.
KIM: Absolutely. There was this one experiment of researchers looking into the bits of DNA from other animals around these flowers, it’s called EDNA, environmental DNA, and so our flowers actually sustain a whole food chain.
The flowers attract over 100 species of animals to feed on the nectar and pollen, and those birds and insects are in turn predated on by other birds. There’s a whole food chain that’s being sustained by these flowers.
DINGMAN: Yes, and one of the other insights that I gather has come out of this newly intensive study of the flowers is their growth pattern, right?
KIM: Yes, so in 2021, there was a massive super bloom event, many, even residents noticed that the saguaros in their, in their backyards or on the street seem to be erupting in flowers, producing flowers, not just on the tips of their limbs or on their heads, but also all down their torsos and their hips.
And scientists do think that this could be a sign of extreme heat just because it does correlate with the long term weather patterns, but the jury is still out whether this is necessarily a good thing or a bad thing.
Flowers are the start of producing the seeds that would eventually become saguaros, so the more flowers you produce could be a good thing in terms of like potentially trying to grow more seeds and produce more progeny basically, but it could also be a sign of something massively going around the environment.
DINGMAN: Speaking of the scientists, one of the projects that is looking at this is called Flower Power, which is a great name. Tell us a little bit about the flower Power Project.
KIM: So these are scientists along with several volunteers are taking photos of these saguaros with 30-foot long selfie sticks and then having these records of these photos of these flowers saved in an archive so they can keep coming back to the data and ask new questions from this big archive of images, basically.
DINGMAN: Yes, in your piece you have there are these wonderful pictures of the scientist with the giant selfie stick standing next to the saguaros, it’s kind of a funny image.
But as a result of that, it seems like we’re able to see these extreme closeups of these flowers about which so little is known and kind of start to understand them for the first time.
KIM: Yes, exactly, it’s really hard to monitor these saguaro flowers because they’re also so tall. Some scientists have been trying to use binoculars or climbing onto like up the hill if they’re on a slope just to look down at the flowers to make sure they’ve counted it correctly, but the selfie, it’s ingenious, I think.
DINGMAN: Yes, well, and it’s also so funny to me that, you know, the saguaro cactus blossom is the state’s official flower, and yet we know so little about it.
KIM: Yes, it takes a lot of patience, it’s not easy to study the saguaro in general because they live so long and scientists have less than a century worth of data when it comes to just the saguaro itself. And these plants live over 200 years, so it’s hard to come up with anything definite to say about the saguaros if you haven’t observed a single saguaro over its entire full natural lifetime.
DINGMAN: One other thing, Kim, that I realized we should add here is that we’re talking about the study of these flowers being a recent phenomenon in one sense, but as you point out in your piece, the Tohono O’odham have been observing these flowers for many generations, correct?
KIM: It depends on what you mean by observing, they haven’t been like keeping track of the flowers or selling the flowers themselves, but of course, they respect the, the saguaro themselves, they regarded as like they have their own agency basically.
But yeah, one source I spoke with says that whenever she sees the flowers, she starts to anticipate the arrival of the blood red fruit it produces. So in a way that those flowers herald that tradition as well as herald the Tohono O’odham New Year that begins with the fruit harvesting. So I guess when you start seeing the flowers, you have something to look forward to in this tangible thing of beauty that’s embodied by the flower.
KJZZ’s The Show transcripts are created on deadline. This text is edited for length and clarity, and may not be in its final form. The authoritative record of KJZZ’s programming is the audio record.
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