Saguaro Land: Why plants native to Arizona aren't always easy to grow

Seed libraries are growing in popularity. For a while now, we’ve been able to go to the Phoenix Public Library and “check out” seeds, and seed sharing events are popping up all over town — particularly with spring upon us.

In 2020, Danielle Carlock started a seed library for the Maricopa County Community College District with a twist. All of the seeds in her library are native to the Sonoran Desert.

Now you might think that native plants are easier to grow here. Conditions should be prime, right? Turns out that’s not the case. Even Carlock, a seasoned desert gardener, struggles with some seeds. And since you check out the seeds but don’t have to return them (like a book), no one knows if you had any luck — until now.

Carlock has created a survey to ask gardeners to let her know what kind of luck they are having with her seeds. She has a few preliminary results to share and other ideas about how to get native plants growing.

Danielle Carlock

Full conversation

GILGER: I spoke with her more about the project, how it's grown and what's happened to the seed packet she's given out so far. And we're talking a lot of seeds.

CARLOCK: And we've given out 12,000 seed packets so far.

GILGER: 12,000 seed packets. That’s a lot.

CARLOCK: I know you don't know where all this seed is coming. It's amazing because I'm the primary gatherer of the seed. I personally collect and touch all the seed.

GILGER: Wow.

CARLOCK: So it's a lot of seed.

GILGER: Wow. Tell us about where you get it all and getting it out to folks.

CARLOCK: So it's mostly sourced from the Tonto National Forest. So the seed is mostly wild collected. And that means I go through a permitting process to get permission to actually collect on the Tonto National Forest. And that's an important piece is that folks shouldn't go out and collect seed, you know, kind of on their own. It does require, you know, a permitting process. I also collect on the campuses. SCC has an amazing garden of native plants that I've been collecting from and my home garden. I do sometimes take some donations from folks that are that I trust that I know that they have what they say they have, and I can verify that before I take that in. So I have taken some donations as well, which are always welcome.

GILGER: Tell us about the plants themselves. Like, what do we mean when we say native plants? Like, I don't even know if I could name one, honestly.

CARLOCK: Yeah, sure. You know, we have thousands of native plants. And when I first came out here, I thought that I knew them in the first, you know, couple of months. And it was those ones that are really iconic, like the saguaro or maybe like a mesquite tree. But the more that I did hiking and going out on the trails and then using the iNaturalist app and then kind of learning from different botanists and people that knew this stuff, I realized that, wow, there's like thousands of native plants.

And there are trees, there are shrubs, there are vines, there are ground covers, there are cacti, there are annuals and grasses, so many different types of plants. And these are the plants that have evolved here over, thousands and thousands of years. And they all have interrelationships with each other and with the other living things, in the Sonoran Desert. And it creates a tapestry of life that is really interrelated. And so it's really important to support our native plants because we can't have an intact Sonoran Desert without those native plants.

GILGER: Yeah. So you have given out, you said 12,000 seed packets. And it's been going on for some time now, but you sort of send them off into the world and then do you wonder what happens to them? Do you know if people are able to grow the seeds?

CARLOCK: Yeah, so that's really interesting. So when I founded the seed library, that was one of my biggest worries is that, you know, I knew it was harder to get native seeds to germinate compared to like your food crops. because food crops have been bred by, humans for thousands and thousands of years to germinate quickly. And so, you put in some lettuce or something like that, and seven to 10 days later, you have little seedlings popping up. It's not the same for native plants because they have sort of built-in mechanisms to make sure they don't germinate when the conditions aren't ideal for them. Otherwise, you know, they have a one chance, you know, they're one and done. If they germinate at the wrong time and there's not enough water or it's too cold or something like that, that's the end of their life.

So they have built-in mechanisms to only germinate under NDL conditions, and it's a little bit harder to get those conditions. That's the challenge. And so what we're doing is we're trying to get folks to report back on their experiences with these packets that have gone out. So I've got a survey running right now to ask people their experiences and trying to understand where the successes were, where the failures were, so that we can maybe do some more targeted education outreach and try to get better germination. Because the one thing I certainly don't want is for folks to get discouraged about native plants because they took some packets and it didn't work for them.

GILGER: Right, I mean, it seems counterintuitive, right? Like you'd think if it's a native plant, it grows here on its own out in the middle of the desert. Why would it be hard for me to start? But it takes these kind of specific conditions. What have you learned so far from folks in this survey?

CARLOCK: Some folks have had success and some haven't. I'm going to dig a little deeper. Some of them have given me permission to follow up with them and do a little interview with them to learn more. When I do know that, like certain seeds have specific requirements, like some of them need a period of cold. before they will germinate. So this will be like your spring wildflowers. They actually need to go through like a cold period in the wintertime. So you typically sow them in October or November or maybe September. So if somebody sowed those seeds like in February, it's too late because they have to go through that cold period and then germinate. So that's one example. Or some seeds require what's called stratification. And this would happen naturally. So the seeds, they're subjected to different, you know, pressures down in the soil and in the gravel and things like that, kind of break open a part of the seed so that water can get in and they will germinate. And if they don't have that, it's called scarification. If you don't have that process, then they won't germinate.

So, but you can replicate this if you're going to like start them indoors, you could scratch them with a little file. And that's called stratification. You know, that's mechanical stratification. And then that opens up the seed to allow water to get in. And once they can imbibe water, they can germinate. So if I know that about a seed, I can provide that information on the packet. But we don't always know what seeds need what kind of treatments. And some may not need any treatments and some don't for sure. But a lot of it isn't known yet. There hasn't been really controlled trials on a lot of these native species to know what their needs are.

GILGER: It sounds like you're starting to do that all yourself. Like you are the base of knowledge for this.

CARLOCK: No, there's other people involved. And actually the Center for Native and Urban Wildlife at Scottsdale is doing a lot of work on that too to propagate native plants. but there hasn't been enough of it.

GILGER: Are people surprised, Danielle, that it's this hard or that it's this complicated or that there's this much, I guess, like science behind it?

CARLOCK: Yeah. I mean, I think that when the actual requirements of the plant and you carry them through, it's relatively easy. Or if the plant doesn't require any pre-treatment, for example, I've got one, pink parrhesia, I just have to sow it and keep it wet and I sow it indoors, you know, in little, you know, little trays and keep them moist and they'll come up in about 10, maybe 15 days. And so that one's a pretty easy one. And there's other ones like that. But then there's others that are much harder and some of them need a double, two processes. Like they might need a cold period and some sort of mechanical stratification or something like that.

GILGER: That's really interesting. So you're continuing to get these seeds out there, and I know that was kind of your main goal from the beginning. What kinds of success stories have you heard? I mean, as you're doing this research and as you're hearing, I'm sure back from some people who you've given these seeds to, you've experienced, I know, a lot of joy from just bringing this kind of nature, this kind of natural Sonoran landscape into your own yard. Do you think you're able to spread that in this way? Is it working? 

CARLOCK: In that sense? I do hear back from some folks. I had someone that wrote me and said, I grew out 100 milkweed plants from the seeds you gave me and I gave them out for free through my little seed library, plant stand and little seed library. So people got to just take those plants and I thought that was amazing. And then I have someone else who took a lot of different seeds and got germination. And she's been really excited about learning the different plants and seeing the wildlife coming to her yard. So it is working. It's just every seed that goes out is not going to germinate. Because in the wild, that's true too, right? That's why plants, they produce many, many, many, many seeds with only a few of them that will ever maybe germinate and become a full plant themselves. That's just how nature works.

GILGER: That's just how nature works. All right, we'll leave it there. That is Danielle Carlock, a librarian at South Mountain Community College, who created Native Seed Library. Danielle, thank you so much for coming back on the show and best of luck.

CARLOCK: Thank you so much.

EDITOR’S NOTE: KJZZ is licensed to the Maricopa County Community College District.