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Monarchs and Milkweed · In the Garden with UC Master Gardeners

0:05
SPEAKER_02: Sounds of the Antieter Kingdom on 88.9 FM KUCI in Irvine.
0:13
SPEAKER_00: The opinions and views expressed in this program do not reflect those of KUCIDs management or the UC Board of Regents.
0:23
SPEAKER_02: People are drawn to monarch butterflies for a combination of scientific, aesthetic, and emotional reasons.
0:30
SPEAKER_02: Few insects have captured the public's imagination the way monarchs had.
0:35
SPEAKER_02: I'm Master Gardener Bill here to talk about both monarchs and milkweed on this edition of In the Garden with University of California Master Gardeners here on 88.9 KUCI.
0:47
SPEAKER_02: We have Master Gardener and Ecist Tracy Rice in studio with us today.
0:53
SPEAKER_02: Tracy is a working lands partner biologist in Southern California and he works for the California-based wildlife conservation and research nonprofit organization Blue Point Conservation Science.
1:07
SPEAKER_02: Tracy, welcome and please explain your role in Blue Point Conservation and your position there.
1:15
SPEAKER_02: Good morning.
1:22
SPEAKER_01: Point Blue Conservation Science is a California-based environmental nonprofit with a mission to conserve birds, other wildlife, and ecosystems through science, partnerships, and outreach.
1:36
SPEAKER_01: Our 160-ish conservation professionals address climate change, biodiversity loss, and other ecological threats.
1:45
SPEAKER_01: In 2025, we celebrated our 60th anniversary, and we continue to collaborate with land and water managers, fisher folk, ranchers, farmers, government agencies, and others to develop nature-based solutions that benefit wildlife and people.
2:04
SPEAKER_01: From the Sierra to the sea, across the Western Hemisphere, and as far as Antarctica, Point Blue is preparing for the environmental challenges ahead.
2:13
SPEAKER_01: I've been a partner biologist in the Working Lands Group since 2021.
2:18
SPEAKER_01: So in my role, I partner with the USDA Natural Resource Conservation Service and other local partners to support working lands managers in the conservation of natural resources, especially native plants and wildlife, often on privately owned working lands, lands that are managed for food, fiber, or cultural resources.
2:38
SPEAKER_01: So think farms, ranches, orchards and vineyards, tribal lands.
2:44
SPEAKER_01: If I had to frame it in slogans, I provide climate smart solutions for a healthier planet, and I help people help the land.
2:53
SPEAKER_02: And we're also lucky to have you as a master gardener here in Orange County.
2:57
SPEAKER_02: Yeah.
2:58
SPEAKER_01: So I've been a master gardener since I think 2022.
3:03
SPEAKER_01: It felt like a natural fit.
3:05
SPEAKER_01: I grew up gardening, learning about plants, uh, mostly from my great-grandmother, who would also take us on wild drives and almost swerve off the road planting out pointing out her favorite native plants.
3:17
SPEAKER_01: Uh, and so I wanted to make sure that when I'm assisting folks, uh especially like advising in the establishment of native plants, that I had the science-backed information as well as, you know, what I've picked up through my life in formal education.
3:36
SPEAKER_02: Absolutely, and that's what we do at Master Gardeners, is we teach people the UC-based science, and we bring science into gardening.
3:46
SPEAKER_02: And today we're going to talk about monarchs.
3:49
SPEAKER_02: And monarchs are strikingly beautiful.
3:51
SPEAKER_02: Their orange wings with bold black veins and white spots make them one of the most recognized butterflies in the world.
3:59
SPEAKER_02: They certainly do not blend in with their environment.
4:02
SPEAKER_02: So why the bright colors?
4:04
SPEAKER_01: Absolutely.
4:05
SPEAKER_01: Uh, this is a phenomenon known as aposemitism, which is a fancy word for like warning coloration.
4:14
SPEAKER_01: Um it's very similar to what you see in like poison dart frogs or skunks, or if you think of an auditory cue, the rattle of a rattlesnake.
4:26
SPEAKER_01: Um, this is an evolutionary process that occurred where monarchs themselves are toxic, and we'll get into that in a little bit uh in some future questions.
4:40
SPEAKER_01: But just being toxic doesn't help you as an individual or the population.
4:45
SPEAKER_01: You need to be recognized as toxic.
4:49
SPEAKER_01: And so without anthropomorphizing too much, uh it's easier to remember if you eat something and it tastes bad and makes you sick if it's easily identified visually.
5:03
SPEAKER_01: So that orange and black and white high contrast makes monarchs easy to kind recognize from the perspective of a predator that may encounter them.
5:17
SPEAKER_01: Uh this is also why we see uh a lot of things that look like monarchs.
5:23
SPEAKER_01: Uh there's a principle of malarian mimicry, so you'll see viceroy and queen butterflies that look very similar.
5:32
SPEAKER_01: They also share the trait of being unpalatable and toxic to predators, and it benefits them all if they look pretty much the same.
5:42
SPEAKER_02: So not only do monarchs have these bright colors, but they migrate.
5:46
SPEAKER_02: And their migration is extraordinary, especially because no single butterfly makes a round trip.
5:54
SPEAKER_01: Yeah, pretty much.
5:57
SPEAKER_01: In their native range, which is North America, monarchs are migratory.
6:02
SPEAKER_01: But at this point they've spread to over 90 countries, uh, islands, island groups across six continents.
6:11
SPEAKER_01: Um in those other places, they are resident, they breed year-round.
6:16
SPEAKER_01: We also have some resident populations here in the Americas.
6:20
SPEAKER_01: So in Florida, there's a resident non-migratory population.
6:25
SPEAKER_01: Same thing in Hawaii.
6:26
SPEAKER_01: But if we focus on the I'll do air quotes here, main monarch populations, those are the eastern and western populations.
6:36
SPEAKER_01: I will touch briefly on the eastern population, but because we're here in Orange County, California, when I go into detail from here on out, I'm gonna focus mostly on the western monarchs.
6:51
SPEAKER_01: So we distinguish these populations by where their overwintering and breeding grounds are.
6:59
SPEAKER_01: The eastern population overwinters in central Mexico and then migrates across North America to the east of the Rockies.
7:11
SPEAKER_01: The western population overwinters in coastal groves in California.
7:18
SPEAKER_01: Historically, those were usually cypress groves, but increasingly with the introduction of eucalyptus, they're using eucalyptus now.
7:28
SPEAKER_01: That western population then begins its migration to the east and north through the Central Valley and most of the western states.
7:40
SPEAKER_01: They have four generations per year usually, and that fourth generation is what we call a supergeneration.
7:49
SPEAKER_01: So they are a little bit larger, longer lived, they emerge from their chrysalises in a state of reproductive diapause.
8:00
SPEAKER_01: So their reproductive organs are shrunken, they aren't mating, they after they complete the migration all the way back to the groves, so one single adult makes at least half of the trip itself.
8:17
SPEAKER_01: They're less active, they consume less food resources, and they kind of just hang out in the trees until it's time to begin the cycle again.
8:26
SPEAKER_02: Yeah, and I know here in Orange County, both Doheny State Beach and San Clemente State Beach have been overwintering grounds Doheny not so much anymore because they lost a lot of their old growth eucalyptus, but San Clemente uh still has them, and I know they they do account there, and then you find them up and down the coast through Carmel and San Luis Obispo, and that area is those areas, if I'm not mistaken.
8:52
SPEAKER_01: Yes.
8:53
SPEAKER_01: And I think for folks listening here in Orange County, if you want to see kind of the largest and most reliable nearby overwintering grove, it's in Pismo State Beach.
9:06
SPEAKER_02: Um Yeah, that's a little bit of a drive up the coast, but still uh that that does work.
9:11
SPEAKER_02: So why have monarchs, butterflies, become such an important symbol for gardeners and for conservationists like yourself?
9:20
SPEAKER_01: It's a good question.
9:21
SPEAKER_01: Uh it's a combination of reasons that culminate in the monarch being what conservationists would refer to as a charismatic species.
9:32
SPEAKER_01: So a plant or animal species with widespread recognizability, popular appeal, beauty, uh cultural and symbolic significances that capture our attention.
9:45
SPEAKER_01: So as we just mentioned, monarchs themselves are strikingly beautiful, quite large for a butterfly, which makes them easy to identify.
9:54
SPEAKER_01: They have a fascinating life history and migration pattern that tells a story of resilience that I think we as humans want to relate to.
10:04
SPEAKER_01: You know, a small thing in the world doing something large and impressive.
10:12
SPEAKER_01: I think humans want to live that story themselves.
10:17
SPEAKER_01: Um, there's also, I think, this phenomenon that's been referred to as nature deficit syndrome or shifting baselines, where most people aren't going out day to day looking for butterflies.
10:34
SPEAKER_01: And so monarchs, because they're migratory and have different needs throughout their life cycle, they're one of the few butterflies that we're able to see in home gardens and urban environments that we can easily identify.
10:49
SPEAKER_01: So if you were to ask a random person on the street, can you draw me a picture of a monarch or of a butterfly?
10:56
SPEAKER_01: Nine times out of ten, they're gonna draw something orange that looks like a monarch.
11:01
SPEAKER_01: Right?
11:02
SPEAKER_01: Oh, I'll I'll continue on one more reason why I think monarchs are charismatic.
11:07
SPEAKER_01: There's a deep and still relevant cultural significance.
11:11
SPEAKER_01: So uh across a lot of indigenous cultures in California, even into Mexico, they've historically been seen as a symbol of rebirth, regeneration, resilience, and uh some folks even believe that monarchs represent their ancestors visiting them again.
11:36
SPEAKER_01: And then in recent times, the symbol of the monarch has been taken up by activists and artists as a like symbol for immigrant rights.
11:46
SPEAKER_01: If you think about the monarchs annually, they complete this migration without concern for borders or political lines, and I think folks are relating to that right now.
12:00
SPEAKER_01: So all of those factors make them charismatic, and why I think the average gardener is interested in monarchs.
12:08
SPEAKER_01: From a conservationist perspective, they're what we would call a flagship species.
12:15
SPEAKER_01: So flagship species are often charismatic and at risk of sounding a little cynical, they're great PR.
12:24
SPEAKER_01: So when we are going out to do conservation, oftentimes we're not thinking in a species context, we're concerned with ecosystems.
12:36
SPEAKER_01: So we can sell monarchs relatively easily, but because of their life history, we're conserving multiple habitats that hundreds, if not thousands, of other species rely upon.
12:51
SPEAKER_01: And so when you're trying to get public support or funding, uh a monarch is a nice poster child to have.
12:59
SPEAKER_02: That's uh yeah, that's exactly what I was gonna say.
13:02
SPEAKER_02: So take us through the monarch life cycle, if you would.
13:08
SPEAKER_01: Sure.
13:09
SPEAKER_01: We'll start, we'll focus on the western population again, and we'll start in like February or March with an adult monarch.
13:19
SPEAKER_01: So these are the monarchs that have completed the westward migration back to the overwintering ground.
13:25
SPEAKER_01: They've gone through their diapause.
13:28
SPEAKER_01: As temperatures rise, daylight hours get longer, milkweeds begin to emerge, nectar plants begin to bloom.
13:39
SPEAKER_01: The adult monarchs go, they breed, they lay their eggs on some milkweeds, and then those eggs hatch in about three to five days.
13:51
SPEAKER_01: Uh it depends a little bit upon temperature, how quickly that phase of the life history happens.
13:58
SPEAKER_01: Those eggs hatch into larvae, uh, and the first instar or the first phase of the larvae form.
14:07
SPEAKER_01: Uh it's a tiny little caterpillar, about two millimeters long, and all it really wants to do is eat and grow.
14:17
SPEAKER_01: So it it consumes the milkweed that it was laid upon, grows, and eventually it becomes too big for its skin, at which point it molts.
14:28
SPEAKER_01: Oftentimes it'll eat its molted skin and become a second instar that's a little bit larger.
14:35
SPEAKER_01: And it goes through five of those instar phases before it uh begins the next part of a full metamorphosis.
14:46
SPEAKER_01: So it will at that point be about like 25 to 45 millimeters long, and it looks for a place to pupate.
14:55
SPEAKER_01: They'll often crawl off to a nearby woody plant, and they spin a mat of silk that comes out of its head onto its chosen place, and then hangs from its legs in a J shape.
15:13
SPEAKER_01: Folks will often call it jaying.
15:16
SPEAKER_01: Um, and they will extend a stem or cremaster from their rear end to attach themselves and form a chrysalis.
15:26
SPEAKER_01: And then over the next eight to fifteen days, the larva transforms to an adult butterfly, which eventually emerges.
15:36
SPEAKER_01: Uh that second generation continues migrating across the Central Valley, the western states, uh, lays eggs.
15:45
SPEAKER_01: The second and third generation monarchs tend to hang out uh pretty much in the area where they were born, and then that final super generation at the end of the year will make the journey back to the overwintering sites and start the process again.
16:05
SPEAKER_02: So they've got this fragile life cycle, which you've just talked to about us about, and this is why we're so concerned with monarchs.
16:13
SPEAKER_02: And as gardeners, I know we want to know about milkweed today.
16:17
SPEAKER_02: Sure.
16:18
SPEAKER_02: And there's different types.
16:20
SPEAKER_02: There is a tropical milkweed, often sold in garden centers.
16:24
SPEAKER_02: To me, it the flowers on it look a lot like a lantana flower.
16:28
SPEAKER_02: And there are three native species of milkweed that grow right here in Orange County.
16:32
SPEAKER_02: Let's start with the tropical milkweed.
16:34
SPEAKER_02: Good?
16:35
SPEAKER_02: Not good?
16:37
SPEAKER_01: You're throwing me into the fire.
16:39
SPEAKER_01: It's a little more complicated than that.
16:41
SPEAKER_01: Uh overall, I would say tropical milkweed is better for monarchs than no milkweed.
16:49
SPEAKER_01: But it does present some problems for the species.
16:55
SPEAKER_01: I would prefer to see people interested in monarch conservation grow native species.
17:01
SPEAKER_01: Um, however, semi-recent diet analysis studies have shown that tropical milkweed is the most important larval food source for monarchs in California right now.
17:15
SPEAKER_01: Should it be?
17:17
SPEAKER_01: Probably not.
17:18
SPEAKER_01: Uh, but it is the most abundant on the landscape and it is sustaining that population.
17:24
SPEAKER_01: If we were to rip it all out, you know, with a snap of the finger and not replace it, it would be a catastrophic for monarchs.
17:35
SPEAKER_01: Um but there are some caveats to tropical milkweed that are worth considering.
17:42
SPEAKER_01: First, as a conservationist, I'm interested in preserving biodiversity.
17:48
SPEAKER_01: I think it's cool that different places have different species, and I'm not interested in a world where we homogenize everything so that it looks the same and the total amount of diversity we have worldwide decreases.
18:06
SPEAKER_01: So that's just you know my immediate philosophical take on the matter.
18:11
SPEAKER_02: And I think a lot of people would agree with you.
18:13
SPEAKER_02: We want the the unique thing about gardening and living in California is we've got native plants and insects and animals that exist nowhere else in the world.
18:23
SPEAKER_01: Yeah.
18:24
SPEAKER_01: And so there's other concerns about tropical as it specifically relates to monarchs, in addition to that.
18:32
SPEAKER_01: Um Tropical milkweed is native to Mexico and Central America, not to California's.
18:39
SPEAKER_01: And it behaves differently in its native range than it does here.
18:44
SPEAKER_01: Um in its native range, it behaves like our native milkweeds do here.
18:48
SPEAKER_01: They go dormant each year.
18:51
SPEAKER_01: And that dormancy is important for a couple reasons.
18:57
SPEAKER_01: Um first of all, tropical milkweed that doesn't go dormant uh has the potential to trigger migratory monarchs to begin breeding early.
19:09
SPEAKER_01: And when this happens, monarchs can essentially waste their reproductive potential on what will likely be a failed migration that does not benefit the population.
19:22
SPEAKER_01: The butterflies breed, and best case scenario, the caterpillars are able to consume the milkweed, make it through their metamorphosis, and begin migrating, and then they find that there aren't enough blooming nectar plants on the landscape to fully fuel that migration.
19:43
SPEAKER_02: Um so it's yeah, and what you're saying is it's winter here.
19:47
SPEAKER_02: Yeah.
19:47
SPEAKER_02: So things aren't blooming.
19:49
SPEAKER_02: Yes.
19:49
SPEAKER_02: So the adults have nothing to eat.
19:52
SPEAKER_01: Exactly.
19:52
SPEAKER_01: And then there's also the risk of there not being enough to eat for the caterpillars.
19:58
SPEAKER_01: That too.
19:59
SPEAKER_01: If the tropical milkweed is the only milkweed on the landscape and it exists in like small abundance, what can happen is it's called egg dumping, where the monarch will lay all of its eggs on one plant.
20:14
SPEAKER_01: And these caterpillars are hungry, they mow the whole thing down, but it's not enough food for all of them, and they starve to death before they can complete their full metamorphosis.
20:26
SPEAKER_02: Okay, right.
20:26
SPEAKER_02: So if I've got tropical milkweed, and you mentioned another thing before the show that I think's important, and that's about the systemics that are used by the nursery and tell us about that.
20:38
SPEAKER_01: Okay, yes.
20:40
SPEAKER_01: Great segue.
20:41
SPEAKER_01: I was like, I wasn't done talking about tropical.
20:43
SPEAKER_01: Cool.
20:44
SPEAKER_01: Um that's another issue.
20:47
SPEAKER_01: So there was a recent study of nursery plants and milkweeds, and it was found that the majority of tropical milkweed on the market has been treated with since systemic insecticides.
21:01
SPEAKER_01: Um it makes sense from a business perspective.
21:04
SPEAKER_01: If you've ever seen milkweeds in your garden, you know milkweed aphids go crazy over it.
21:11
SPEAKER_01: Um, if you're trying to grow these things year-round, you don't want to sell a milkweed that has been chewed up by a caterpillar.
21:20
SPEAKER_01: So they will treat these milkweeds with systemic insecticides, which persist in those plant tissues for weeks, if not months.
21:29
SPEAKER_01: And well-intentioned gardeners will plant these milkweeds in their yards, hoping to provide monarch habitat.
21:37
SPEAKER_01: However, these treated plants serve as ecological traps.
21:42
SPEAKER_01: An adult doesn't know that a milkweed has been treated with insecticide or not when it lays its eggs, and so the caterpillars do what they're supposed to do eat the tropical milkweed and get poisoned to death and die.
21:57
SPEAKER_02: Right.
21:58
SPEAKER_02: So if I have tropical milkweed.
22:00
SPEAKER_02: So our native milkweeks they lose their leaves in the winter months.
22:04
SPEAKER_02: Yes.
22:05
SPEAKER_02: So I want to mimic that with my tropical ones.
22:08
SPEAKER_02: I want to cut them back.
22:10
SPEAKER_02: I want to get rid of the old leaf litter and mulch around it so that I'm not overwintering diseases and put fresh mulch down.
22:19
SPEAKER_02: Is that a correct way to maintain my tropical milkweed?
22:24
SPEAKER_01: Yes.
22:25
SPEAKER_02: Okay.
22:26
SPEAKER_01: Uh so my my stance, and I think that that is backed by evidence, is that if you can remove your tropical milkweed and replace it with a native species, that is the most desirable action you could take.
22:43
SPEAKER_01: Um in general, also don't grow tropical or any milkweed within a mile of the coast or any existing or potential overwintering site.
22:56
SPEAKER_01: Um but if you're not able to replace your milkweed or you're just very committed for aesthetic reasons or whatever, you like tropical milkweed, the best thing you can do is try to mimic the life history of our native species.
23:13
SPEAKER_01: So in October, when the native milkweeds would be going dormant, you can cut your tropical milkweed back to just like the first one or two nodes.
23:24
SPEAKER_01: It'll survive and come back in the spring.
23:27
SPEAKER_01: The other benefit of that is it eliminates another one of the potential threats that tropical milkweed presents to monarchs, which is monarchs have evolved alongside a protozoan parasite called OE.
23:45
SPEAKER_01: I hope I don't butcher this Latin, it's ophrocystis electroscera.
23:52
SPEAKER_01: Uh I think we'll remember it as OE.
23:54
SPEAKER_01: OE.
23:55
SPEAKER_01: It's a little single-celled parasite.
23:57
SPEAKER_01: Um monarchs can tolerate small to moderate loads of that, but when those loads get too high, it causes potentially uh outright mortality or just decreased fitness, so deformities in the wings, maybe smaller body size, uh less effective flight and nectaring.
24:22
SPEAKER_01: And so when our native milkweeds die back each year, all of the OE on them also dies.
24:30
SPEAKER_01: But tropical milkweed, when you allow it to persist, is repeatedly getting visited by monarchs who can shed off some of that parasite.
24:38
SPEAKER_01: And if you don't cut it back, that builds up to loads that are so high that you'll start to see monarch caterpillars ingesting that and failing to complete their metamorphosis, often dying in the pupil stage.
24:55
SPEAKER_02: And I like the way you're presenting this to us today of this is the best thing you do, but this is good, because that allows gardeners to make choices, and I think that's important.
25:05
SPEAKER_02: So let's get into our native species.
25:08
SPEAKER_02: Here in Orange County, we have actually three native species: the narrow leaf milkweed, the woolly pod milkweed, and the California milkweed.
25:20
SPEAKER_02: Are these all good for monarchs and which species perform the best in Southern California gardens, would you say?
25:27
SPEAKER_01: All of these are host plants that monarchs can use to breed on.
25:32
SPEAKER_01: I would say for our area here in Orange County, uh the priorities to plant would be woolly pod and California milkweed.
25:43
SPEAKER_01: And that's because they're earlier emerging than narrow leaf milkweed.
25:48
SPEAKER_01: So the conservation priority for monarchs here is to plant those early emerging species, and that's also because monarchs are beginning to leave their overwintering grounds earlier and earlier each year due to climate change.
26:06
SPEAKER_01: They all perform similarly once established in our Southern California Orange County Gardens.
26:16
SPEAKER_02: So I want to look for again the woolly pot and the California over the narrow leaf.
26:21
SPEAKER_02: If you can find it.
26:22
SPEAKER_02: If I can find and source it, and that means I I may need to do uh uh research.
26:29
SPEAKER_02: And I know uh calnative.org will tell you what nurseries carry what plants, which is nice, and uh hopefully I can source that.
26:38
SPEAKER_02: So what's the so you are they all easy to grow, would you say, or are they are there some caveats that you'd like to talk about?
26:46
SPEAKER_01: Once they've germinated, they're pretty easy to grow.
26:51
SPEAKER_01: Uh most of the seeds do require some sort of cold stratification, potentially some scarification.
26:58
SPEAKER_01: So starting with seed is the biggest hurdle to get over.
27:04
SPEAKER_01: But if you have a container plant and outplant it, uh you're very likely to be successful.
27:11
SPEAKER_01: And we can we can get into how to do that if you want to.
27:14
SPEAKER_02: Yeah, we could we can talk about the seeds.
27:16
SPEAKER_02: Hopefully, we'll uh have some time.
27:19
SPEAKER_02: And in fact, that was my next question on the seeds.
27:22
SPEAKER_02: So you said uh cold stratification, does that mean then I put the seeds in the refrigerator or the freezer for a period of time?
27:32
SPEAKER_01: Yeah, so gardeners, conservationists are still working on uh identifying and fine-tuning the best propagation methods.
27:46
SPEAKER_01: So I'll talk from my experience with Asclepius vesicularis, narrow leaf milkweed.
27:53
SPEAKER_01: What I do with that, I put the seeds in a manila envelope and I put them in the crisper of my fridge for a month, if not two months, before I plant.
28:03
SPEAKER_01: Um other species like California milkweed can be a bit harder.
28:08
SPEAKER_01: They might need like heat scarification or uh cold stratification in addition to that scarification.
28:18
SPEAKER_01: But it's doable.
28:20
SPEAKER_02: It it it does work.
28:23
SPEAKER_02: So what time of uh year do I want to plant my milkweed?
28:28
SPEAKER_01: That depends on what you're starting with, if it's seed or if it's a container plant.
28:35
SPEAKER_01: Um I recommend folks start with container plants if they can find them.
28:40
SPEAKER_01: And the best time to outplant those would be here in Southern California, March.
28:46
SPEAKER_01: Um if we're starting with seeds, if you have a greenhouse or able to start indoors, indoors, you can start like October, November.
28:56
SPEAKER_02: Um and that's what we talk all the time about with our uh vegetables, you know, getting started indoors.
29:04
SPEAKER_02: If you grow seeds, I'm gonna start a manila envelope in my CRISPR for about a month, and I want to bring those seeds out so I can begin growing them indoors uh sometime in the fall, late fall, and then I can get the plants large enough to plant in my garden in March.
29:25
SPEAKER_02: If I'm going to put a container in the ground, March is the good month to plant them.
29:30
SPEAKER_02: So let's talk about their growing needs.
29:33
SPEAKER_02: Uh shade, sunlight, what about water?
29:35
SPEAKER_02: Tell us tell us about that.
29:37
SPEAKER_01: Sure.
29:38
SPEAKER_01: So they can do well from part sun to full sun.
29:43
SPEAKER_01: You usually want to plant milkweeds in a spot where they get at least six hours of sunlight per day.
29:49
SPEAKER_01: Um, they are hardy little guys.
29:53
SPEAKER_01: So they thrive in relatively nutrient poor soils as long as they're well draining.
30:01
SPEAKER_01: So if you're starting with seeds, I would recommend you start with a growing medium of two to one uh soil to perlite.
30:13
SPEAKER_01: If you know where you're going to outplant, do one part potting soil to one part native soil to one part perlite.
30:23
SPEAKER_01: If you're propagating without a clear idea of where you're gonna put them or maybe to give away, stick with potting soil to perlite.
30:32
SPEAKER_01: Um you can outplant them.
30:36
SPEAKER_01: Fertilizing is okay, but usually not necessary.
30:41
SPEAKER_01: And in general, uh I'm in favor of applying compost so that you can build your soil health over time rather than the quick flash of chemical fertilizers.
30:54
SPEAKER_01: Um too high of a nitrogen content from those chemical fertilizers can shock and be detrimental to milkweeds if you're trying to grow them.
31:03
SPEAKER_01: The the main thing to be aware of is water.
31:08
SPEAKER_01: And like a lot of plants, especially natives, the quickest way to kill a milkweed is by overwatering.
31:17
SPEAKER_01: So, you know, we never water on a timer or a calendar.
31:22
SPEAKER_01: We want to be paying attention to how the soil feels, how the plants look, but as a starting rule of thumb, I would say no more than once a week.
31:32
SPEAKER_01: Maybe in the summertime, days like today or yesterday when it's mid to high 90s, twice a week.
31:40
SPEAKER_01: But these are native plants that have evolved here, and so once established, they generally don't require irrigation.
31:51
SPEAKER_01: Us gardeners, we like to baby our plants and keep them alive more than Mother Nature does, so you can continue to irrigate for the full lifespan, but after like that first year's establishment, you probably don't need to water anymore if you don't mind potentially losing a plant.
32:11
SPEAKER_01: The other thing I'll mention when you outplant your container plant milkweeds, best practice is to, and it feels like a bummer because you want to provide habitat, exclude monarchs for the first year.
32:26
SPEAKER_01: You really want to give those milkweeds a chance to uh grow robust roots, establish themselves well, and if they are exposed to herbivory from monarchs in that first year, the plant has to pour energy into growing all of its above-ground vegetative mass rather than growing those that strong foundation of root matter.
32:52
SPEAKER_01: So you can use uh like a cage built out of hardware, cloth, or mesh, but I do recommend in that first year be patient.
33:02
SPEAKER_01: I know you want to see the butterflies use this habitat you've put there for them, but you know, give them the Shangri-La rather than uh a motel six.
33:11
SPEAKER_02: Yeah, so let let those uh let those feed easy on my water.
33:16
SPEAKER_02: I don't want a fertilizer because I don't want to overnoy over-nitrogenate uh and I want to use a compost so I build that good soil health, which is exactly what we uh preach at UCANR and how to do things.
33:33
SPEAKER_02: So if I have a deck and I don't have a yard, can I grow native milkweed in a container?
33:39
SPEAKER_01: Absolutely.
33:42
SPEAKER_01: You want to follow just sort of the general guidelines of growing in containers.
33:47
SPEAKER_01: So have the right size container for the root mass that you have present.
33:54
SPEAKER_01: So you won't take, you know, a little seedling and put it in a five-gallon container all of a sudden.
34:00
SPEAKER_01: You're likely to overwater and get root rot.
34:03
SPEAKER_01: But you can up pot over time between seasons.
34:07
SPEAKER_01: The concern about container growing when it comes to like monarch conservation is the extent of the milkweed, the size of it, is going to be limited by that container.
34:24
SPEAKER_01: Uh, kind of as a rule of thumb, the root mass is uh equivalent roughly to the uh herbaceous mass.
34:33
SPEAKER_01: So if you have a small pot, you aren't gonna get a large milkweed.
34:37
SPEAKER_01: And you want to make sure that if you are attracting monarchs to your yard to breed, you have enough forage for them.
34:45
SPEAKER_01: So if you're gonna grow in containers, I would suggest you grow multiple milkweeds.
34:50
SPEAKER_01: That way, caterpillars don't come in, mow the entire thing down, fail to complete their full metamorphosis.
34:57
SPEAKER_02: Yeah, it is kind of counterintuitive when you see your milkweed uh leaves being chewed on, that's a good thing rather than uh rather than, oh my gosh, something's eating my plant.
35:08
SPEAKER_02: So it's a little it's a little different.
35:11
SPEAKER_02: So, what makes milkweed toxic to animals but safe to monarch?
35:15
SPEAKER_02: What is it in that milkweed that uh is toxic?
35:18
SPEAKER_01: Good question.
35:20
SPEAKER_01: So milkweeds they all produce uh chemical compounds known as cardenolides, which are neurotoxins to vertebrates.
35:31
SPEAKER_01: Uh so they taste bad.
35:35
SPEAKER_01: If you have a spinal cord and eat too much of it, you're gonna get sick.
35:38
SPEAKER_01: If you eat way too much of it, it will kill you.
35:42
SPEAKER_01: Um monarchs, through a process called coevolution, have developed limited, although pretty good, tolerance towards those compounds.
35:53
SPEAKER_01: So when species interact with each other over millions of years, an evolutionary arms race takes place.
36:01
SPEAKER_01: So, you know, plants don't think, but if you're a plant, you don't want to be eaten.
36:07
SPEAKER_01: You're sessile.
36:08
SPEAKER_01: So the biggest threat to you is an herbivore.
36:12
SPEAKER_01: If through mutation you develop a compound that tastes bad and is poisonous to uh your would-be predators, that's you know a great adaptation.
36:24
SPEAKER_01: And so milkweeds face the selection pressure to become increasingly toxic.
36:32
SPEAKER_01: Butterflies need a food source for their larvae to grow upon.
36:38
SPEAKER_01: And again, through mutation, just luck of the draw, some monarch caterpillars or proto-monarchs at this point, were able to tolerate those cardanolides.
36:50
SPEAKER_01: And because of that, as they eat it, they incorporate that toxic compound into their own body tissues, therefore becoming unpalatable and toxic to their predators.
37:05
SPEAKER_01: Why they're uh not affected, I don't know for sure, but that's how it happens.
37:12
SPEAKER_02: It's what they evolved doing and the way that they created the niche to survive.
37:17
SPEAKER_01: Yep.
37:18
SPEAKER_01: I will note they're not immune to cardenolides.
37:24
SPEAKER_01: So at high enough concentrations, even monarch caterpillars cannot withstand the toxin.
37:31
SPEAKER_01: And that's we'll loop back to another point about tropical milkweed.
37:36
SPEAKER_01: So tropical milkweed is higher in cardanolides than many of our native species, and the concentration of cardanolides in milkweeds scales positively with temperature.
37:50
SPEAKER_01: I see.
37:50
SPEAKER_01: So with rising global temperatures and climate change, that's also something to be aware of that it could get to the point that these tropical milkweeds become so toxic they're not even a functioning food source for monarch larvae.
38:07
SPEAKER_02: And that hopefully is going to be way down the road.
38:10
SPEAKER_02: Yes.
38:11
SPEAKER_02: I also want to tell people that if you're listening in Canada or you're listening in another state, visit your agricultural natural resources website to find out what native species of milkweed grow in your area.
38:26
SPEAKER_02: And if you're in the eastern areas of the United States or uh eastern Canada, you can find out uh those plants that the eastern species thrive on, and you can do the same thing because tropical milkweed is sold in nurseries uh all over the world now, and we're actually getting populations of monarchs in the Philippines and in Spain and Portugal and places where they don't normally live.
38:56
SPEAKER_02: And again, we want to keep the species that are unique to unique areas of the world.
39:02
SPEAKER_02: Absolutely.
39:03
SPEAKER_02: So, besides milkweed, uh adult monarchs feed on nectar plants.
39:11
SPEAKER_02: So talk about the nectar plants that a gardener could grow that would attract the adults for feeding.
39:18
SPEAKER_01: Sure.
39:19
SPEAKER_01: So monarch adults are generalists when it comes to their nectar need.
39:26
SPEAKER_01: So I don't want to like without evidence name any specific native species that are great nectar plants for monarchs.
39:35
SPEAKER_01: Generally speaking, if you plant what is native to your area and it is a a blooming species, something that produces flowers, monarchs can use it.
39:47
SPEAKER_01: What I like to advise people to do is to focus on having consistent, diverse blooms, if you're concerned with monarchs, during their migratory season.
40:01
SPEAKER_01: So from roughly March into October, really focus on what native plants do I have blooming at a time?
40:11
SPEAKER_01: Two to three species blooming at any given time is pretty good, especially for uh these more uh anthropocene uh novel ecosystems.
40:25
SPEAKER_01: I here in Orange County, uh, you know, I'm thinking like what what grows well, what blooms for a long period, so buckwheats, um urinecilias, the the bush sunflowers are pretty good.
40:40
SPEAKER_01: Um Penstamens are a great plant that looks good in And they're beautiful.
40:46
SPEAKER_01: They're beautiful, that's what I was gonna say.
40:47
SPEAKER_01: They look good in a garden.
40:49
SPEAKER_01: Um and going back to this flagship species concept or um charismatic species, when you're providing these nectar plants on your yard, you're supporting so much more than just monarchs.
41:04
SPEAKER_01: Um you're supporting native bees, hummingbirds, bats, moths, etc.
41:11
SPEAKER_01: And this concept of diversity begets diversity is something that you can keep in your mind as a mantra.
41:19
SPEAKER_01: Uh if I want to support monarchs or any native species, the best thing I can do is plant native species.
41:26
SPEAKER_01: You can learn about the species that are native to where you live.
41:30
SPEAKER_01: Uh like you mentioned from your agricultural and natural resources or local extension.
41:38
SPEAKER_01: There are online resources that are great as well, including Calscape.
41:43
SPEAKER_01: Calscape, calnative.org.
41:45
SPEAKER_01: Yep.
41:46
SPEAKER_01: All good.
41:46
SPEAKER_01: If you're really interested, Calscape has a cool feature where you can search by uh species of butterflies and identify what would be host plants.
41:59
SPEAKER_01: Uh you can also, if you want just like a list of here are some species that are preferred by bees and butterflies, I recommend checking out resources from the Xerces Society for Invertebrate Conservation.
42:13
SPEAKER_01: And that's spelled with an X.
42:16
SPEAKER_01: So X-E-R-C-E-S.
42:18
SPEAKER_02: Yeah, that's pretty familiar.
42:20
SPEAKER_02: And you know, we so talk so much about this on this program about go native.
42:25
SPEAKER_02: And it regardless of where you live, go native.
42:28
SPEAKER_02: Plant your native plants that that live there and you're going to support the native organisms that live within your region of the world.
42:36
SPEAKER_02: So, what common gardening practices and mistakes accidentally harm monarchs that gardeners might do?
42:44
SPEAKER_01: Hmm.
42:45
SPEAKER_01: Accidents.
42:47
SPEAKER_01: I would say maybe in home gardens, one of the easiest accidents to make is not pointing out the native species that you want to keep to your gardener.
42:58
SPEAKER_02: I see.
42:59
SPEAKER_01: If someone came through and weed whacked your milkweed, that could harm monarchs.
43:04
SPEAKER_01: I think the other common one in home gardens is widespread, oftentimes unnecessary pesticide use.
43:14
SPEAKER_01: So um there are pesticides that can be directly toxic and cause mortality to monarchs, but there are also things that you wouldn't even think of, like um weed killers, that can drift, and that exposure causes sub-lethal effects.
43:33
SPEAKER_01: So decreased effectiveness in migration or foraging efficiency, things like that.
43:38
SPEAKER_01: So pesticide use, I would say, is another one of the accidental ways or the ways that people aren't you know often cognizant of that can have detrimental effects on monarchs.
43:51
SPEAKER_02: And it is the type of uh treatment that uh is a systemic, and systemic means that the root of the plant.
44:00
SPEAKER_02: Takes up the ta uh the toxin and it stays within those plant tissues for weeks to maybe even months and it continues to randomly kill everything.
44:11
SPEAKER_02: Good insects that target insects, so systemics are something else you want to concern yourself with.
44:18
SPEAKER_02: What about organic things?
44:20
SPEAKER_02: Are they safe for butterflies and monarchs?
44:23
SPEAKER_02: That's a good question.
44:25
SPEAKER_01: Organic doesn't necessarily mean safe.
44:29
SPEAKER_01: So, for example, if if we poured two cups right here, I poured a cup of vinegar, you poured a cup of Roundup, and we started drinking.
44:37
SPEAKER_01: Vinegar's organic, but I would die before you did of drinking Roundup.
44:42
SPEAKER_01: It's more toxic, right?
44:44
SPEAKER_01: Um so organic says nothing about the toxicity of a chemical.
44:50
SPEAKER_01: You can rely upon the UC IPM uh active ingredients database to learn more about the danger that pesticides present to wildlife, uh water quality, etc.
45:07
SPEAKER_01: Overall, I don't want to demonize pesticides completely, be aware of their risk, but they are a tool that should sometimes be used, and I recommend that people follow an integrated uh or what we're now transitioning to calling sustainable pest management framework where you are monitoring for your pests, you are engaging in cultural practices, physical practices, all of that before you ever get to chemicals.
45:39
SPEAKER_02: Yeah, it's it's and again, it's what we call integrated pest management or IPM.
45:45
SPEAKER_02: Yes.
45:46
SPEAKER_02: Is a water station for my monarchs or my butterflies important?
45:51
SPEAKER_02: And what should that be like?
45:53
SPEAKER_01: Definitely, uh just like any living thing, or most living things, they require water.
45:59
SPEAKER_01: Uh monarchs engage in a behavior called like puddling or ponding to drink.
46:04
SPEAKER_01: So they need shallow water.
46:07
SPEAKER_01: Um so like an easy way to provide water to monarch butterflies is you get one of those terracotta uh trays that they sell for pots that I don't know why anyone uses for that purpose.
46:20
SPEAKER_01: But they go in the you put your pot in and it contains the water, right?
46:24
SPEAKER_01: Yes, yeah, you can fill that up with water.
46:26
SPEAKER_01: Uh that's also going to provide water for birds, bees, you know.
46:31
SPEAKER_01: Try to think holistically.
46:33
SPEAKER_01: Water's a great thing to have.
46:34
SPEAKER_02: And you want to keep it shallow and if you change the water often enough, then you don't have to worry about mosquitoes.
46:40
SPEAKER_02: Yep.
46:41
SPEAKER_02: Do you put like a little cork in there to float so they can land on the cork?
46:46
SPEAKER_02: No.
46:47
SPEAKER_02: I haven't done that.
46:48
SPEAKER_02: I I've heard some uh some gardeners do it.
46:52
SPEAKER_02: I don't see a problem with it.
46:54
SPEAKER_02: Okay.
46:54
SPEAKER_02: Um that's good.
46:56
SPEAKER_02: Are there additional butterflies besides monarchs that deserve a gardener's attention?
47:01
SPEAKER_02: Oh, absolutely.
47:03
SPEAKER_02: What would some of those be?
47:05
SPEAKER_01: Um, now you're putting me on the spot.
47:07
SPEAKER_01: Uh here in Southern California, we have a couple endangered or like imperiled species.
47:12
SPEAKER_01: Kino checker spot butterfly is one of conservation concern.
47:17
SPEAKER_01: I think also like I'm a big proponent or yeah, promoter of this concept of keeping our common species common as well.
47:29
SPEAKER_01: So, you know, cabbage whites, they're out there, and they're also potentially an agricultural pest, but they're a native species.
47:38
SPEAKER_01: Um your tiger swallow tails.
47:42
SPEAKER_01: In my ideal world, folks would garden in a way where it meets their needs, be that enjoyment of a hobby, producing food in a way that is most compatible with uh maintaining biodiversity.
47:58
SPEAKER_01: So, you know, I love monarchs, they're cool, but I'm interested in ecosystem conservation, not just single species.
48:06
SPEAKER_01: So uh I'm concerned with native bees, other butterflies, moths, there's a everything.
48:14
SPEAKER_01: Everything.
48:15
SPEAKER_01: Uh especially our insects.
48:17
SPEAKER_01: It's been dubbed the insect apocalypse, and depending on what source you read, we've lost probably like thirty percent of insect biomass worldwide in the last forty years.
48:31
SPEAKER_01: Some regions have lost 76% of their insects.
48:36
SPEAKER_01: Um so yeah.
48:38
SPEAKER_02: So in closing, if you could leave everyone with one message about monarch conservation, what could it be what would it be?
48:47
SPEAKER_01: One message.
48:49
SPEAKER_01: I would say you can make a difference.
48:53
SPEAKER_01: On a population scale, your yard isn't gonna make a huge impact, but you have the potential to provide nectaring, breeding habitat for a suite of species, and you have the ability to become educated, impassioned, and empowered, talk to your neighbors, and together we can make radical positive change for people and wildlife.
49:19
SPEAKER_02: Oh, I love that.
49:20
SPEAKER_02: Despite weighing less than a gram, monarchs navigate across an entire continent using a combination of the sun's position, an internal biological clock, the Earth's magnetic field.
49:32
SPEAKER_02: Scientists like Tracy continue to study exactly how they accomplished this incredible feat.
49:38
SPEAKER_02: Tracy, thank you for joining us today.
49:41
SPEAKER_02: And join us next week for another episode of In the Gardener with UC Master Gardeners.