All Flourishing Is Mutual
Growing With Professor Brown
All Flourishing
Is Mutual
Happy Sunday, everyone.
This week's newsletter has a lot in it, so here is the plan.
We have some important updates for students — including news about two of our classes, and what to expect in each course this week. There is also information about a free tree program for kids with a registration deadline coming up fast.
In the garden, we have a brief update from my parents' backyard — the arborist situation took an unexpected turn — and then two longer topics I've been meaning to dig into. First, we will spend some time with the Three Sisters, one of the most beautiful and enduring examples of companion planting in the world. And then we will look at the relationship between monarchs and tropical milkweed.
Finally, the Thought of the Week is about interdependence and reciprocity — ideas that tie almost everything in this newsletter together.
Let's grow.
For Students
An Update on Two Classes
Both the Tuesday 10:30 AM Regenerative Gardening class at Palomares Park Community Center and the Wednesday 3:00 PM Sustainability class at the San Dimas Senior Citizen Center have been officially cancelled due to low enrollment. I received the email on Friday.
I tried. I want you to know that. And I know that some of you had just recently joined those classes, and I am sorry — that timing is particularly frustrating, and it is not lost on me.
If you were enrolled in either of those classes, please reach out to me. I will personally help you find another section that works for your schedule. You will not be left without a class.
Coming Up This Week
Regenerative Gardening (In-Person and Online)
This week we are covering Principle 2 of the Eight Principles of Regenerative Gardening: "Use knowledge as power." We will also have a special group discussion — one of my favorites to run — where we break into small groups and answer this question together: What advice would you give a new gardener that you wish someone had given you when you were just starting out? Each group will share their favorite insights at the end.
We will also be covering plant propagation, including a demonstration of the paper towel seed germination technique. If you are coming to an in-person session, I will have seeds and paper towels on hand so we can try it together.
Fundamentals of Sustainability (Online Only)
As a reminder, the in-person Sustainability class has been cancelled, but the online section is continuing. This week we move into Modern Environmental and Sustainability Leaders — examining key figures in contemporary environmental movements, their contributions, and their lasting impact on both global and local efforts.
We will also be spending time on scientific literacy: how to find trustworthy information, how to evaluate sources, how to navigate scientific databases, and how to efficiently read research papers. This is a skill that will serve you in every area of your life, not just in this class.
Regenerative Gardening at the California Conservation Corps
This Friday is a work day — plan on being outside and active for most of the class period. The goal this week is planting day and garden infrastructure. Groups will be finalizing their section prep, selecting plants appropriate for their conditions, learning planting techniques and initial watering, building simple critter protection systems for rabbits and squirrels, and covering the basics of mulching and why it matters.
One note: this plan depends on purchases being made throughout the week, so there is a small chance the specifics may shift. Whatever happens, come ready to work.
Free Trees for Kids — Register by March 15th
This one is worth passing along to anyone with children or grandchildren in the area. The Neighborhood Forest program offers free trees to kids through participating local schools and libraries. To receive a free tree, a nearby school or library needs to be involved in the program, and registration closes on March 15th — that is coming up fast.
Find all the details and register at neighborhoodforest.org/get-free-trees/
In the Garden
Parents' Backyard — A Brief Pause
I had planned to give a fuller update on my parents' backyard project this week, but we had an unexpected interruption. Our arborist was scheduled to come out on Saturday, but had to cancel due to a tree emergency caused by the high winds we have been having. Entirely understandable — but it means we are on hold until we can reschedule.
I will have a proper update next week. In the meantime, the raised bed project is paused.
The Three Sisters
Few things in the gardening world carry as much meaning — ecologically, culturally, and practically — as the Three Sisters. Corn, beans, and squash have been grown together by Indigenous peoples of the Americas for centuries, and there is a reason the tradition has endured.
Before we talk about how to grow them, I want to share two videos that speak to why they matter. The first is a brief telling of the legend of the Three Sisters, and the second features an Oneida elder speaking about what the Three Sisters garden means to their community. I encourage you to watch both before you plant. Understanding the story behind a plant changes the way you care for it. The third video describes the planting process.
The Legend of the Three Sisters An Oneida Elder Speaks About the Three Sisters Garden How to Plant the Three SistersWhen to Start Sowing
You may have heard me tell classes to wait until nighttime temperatures are consistently above 55°F before planting corn. That is a reasonable rule of thumb, but the more precise target is actually soil temperature — you want the soil itself to be at least 55°F, not just the air. The distinction matters because soil holds cold longer than air. On a warm spring day, the air might read 65°F while the soil a few inches down is still sitting at 48°F. Planting into cold soil stalls germination and invites rot.
Near Pomona, soil temperatures in the upper few inches generally reach the 55–60°F range reliably by mid-to-late March in most years, though a warm February can push that earlier and a cool spring can push it later. If you want to be precise, a simple soil thermometer is one of the most useful and underrated tools in a gardener's kit. Measure a few inches down in the morning, when the soil is coolest, and use that as your guide.
The Planting Sequence
Once your corn is in, patience is important. Let it grow to roughly knee height before introducing the beans — this gives the corn stalks enough structure for the beans to climb. When you do plant beans, go with two to three seeds per corn stalk. These must be pole beans, not bush beans. Bush beans will not climb the corn and will compete rather than cooperate. Let the beans begin to climb and establish themselves before finally bringing in the squash. The squash fills in the ground level, shading out weeds and keeping the soil cool and moist.
Layout Matters
There are established planting patterns for the Three Sisters and I strongly encourage you to look up a few diagrams before you begin. Spacing affects how well the system works. The plants need to be close enough to support each other but not so crowded that they compete for light. Experiment — the Three Sisters is not a rigid formula, it is a framework.
Variety Suggestions for California
For corn, heirloom varieties tend to be a great fit for this planting style. Hopi Blue and Golden Bantam are both beautiful and productive. For beans, Cherokee Trail of Tears pole beans have deep cultural roots and grow well here — Rattlesnake pole beans are another reliable choice. For squash, Hubbard and Butternut both do well in our climate and are vigorous enough to hold up their end of the partnership.
Monarchs and Tropical Milkweed
I want to tread carefully here, because I know this is a topic that brings up strong feelings — and I understand why. Many of you have planted tropical milkweed (Asclepias curassavica) with genuine love for monarchs. The plant is beautiful. The butterflies are drawn to it.
I am not here to tell you what to do. What I want to do is share some research and ask you to read it with an open mind.
Two peer-reviewed studies have been looking at how tropical milkweed interacts with monarch health — and the picture they paint is worth understanding.
The first, published in the journal Ecology in 2018 by Faldyn, Hunter, and Elderd, examined what happens to monarch larvae feeding on tropical milkweed under warmer temperatures. Tropical milkweed already produces significantly higher concentrations of cardenolides — the chemical compounds monarchs use for defense — than most native milkweeds. Under elevated temperatures simulating future climate conditions, those concentrations increased to levels that appeared to cross a tipping point, dramatically reducing monarch survival rates. The authors describe this as a potential "ecological trap" — a situation where monarchs are drawn to a plant that once served them reasonably well, but that may become increasingly harmful as temperatures rise.
The second study, published in the Proceedings of the Royal Society B in 2015 by Satterfield, Maerz, and Altizer, looked at disease dynamics in monarch populations. When tropical milkweed is present year-round in mild-winter climates — which describes much of coastal and Southern California — some monarchs stop migrating and become year-round residents instead. The research found that these non-migratory, resident monarchs showed significantly higher rates of infection with OE (Ophryocystis elektroscirrha), a debilitating protozoan parasite. Migration, it turns out, acts as a natural disease-control mechanism. When the migration stops, the parasite builds up.
Faldyn, Hunter & Elderd (2018) — Ecology Climate change and an invasive, tropical milkweed: an ecological trap for monarch butterflies Satterfield, Maerz & Altizer (2015) — Proceedings of the Royal Society B Loss of migratory behaviour increases infection risk for a butterfly host — Free full text via PMCNeither of these studies is trying to make you feel bad about your garden. They are doing what good science does — looking carefully at a complicated situation and sharing what they find. I share them with you not as a verdict, but as an invitation to sit with the evidence and think it through.
If you are interested in transitioning toward native milkweed species, I am happy to help you find some. Narrowleaf Milkweed is an excellent choice for our region.
Thought of the Week
All Flourishing Is Mutual
Robin Wall Kimmerer is a botanist, a member of the Citizen Potawatomi Nation, and the author of Braiding Sweetgrass — a book I return to often and recommend constantly. Her work sits at the intersection of Indigenous wisdom and Western science, and if you have not read it, I hope you will.
One of the central ideas she returns to again and again is reciprocity. Not as a transaction — not giving so that you can receive — but as a way of understanding the fundamental nature of living systems. Plants give. Soil gives. Water gives. And healthy ecosystems are built on that flow of exchange between beings who depend on each other.
Kimmerer writes that in the Indigenous worldview, the gifts of the earth are not resources to be extracted. They are relationships to be honored. The goal is not to take and move on, but to participate — to receive what the living world offers and to give something back in return.
This week's newsletter is, in many ways, a study in that idea.
The Three Sisters is one of agriculture's most elegant demonstrations of interdependence. Corn, beans, and squash do not merely tolerate each other — they support each other. The corn provides structure. The beans fix nitrogen and feed the soil. The squash shades the ground and holds moisture. Each plant gives something the others need. None of them thrive as well alone as they do together. That is not a coincidence. It is the result of generations of careful, reciprocal observation between human beings and the plants they grew alongside. Indigenous farmers did not engineer this system with a spreadsheet. They listened to the land.
The monarch and milkweed question this week points toward the same principle, but from a harder angle. Many of us planted tropical milkweed with the simple hope of helping monarchs — and for a long time that seemed like a straightforward act of care. What the research is beginning to show is that the ecological relationships surrounding monarchs are more complex than many of us realized. Parasite dynamics, migration patterns, and warming temperatures can shift the balance in ways that are not immediately obvious. The intention to help is real, and it matters. Reciprocity simply asks us to keep learning, to pay attention to what the science is telling us, and to adjust our practices as our understanding grows.
Kimmerer also has a newer book, The Serviceberry, which I have been reading (again) lately. In it she describes how the serviceberry tree distributes its abundance to meet the needs of its whole community. Its guiding principle, she writes, is that all flourishing is mutual. You cannot truly thrive at the expense of the system you belong to.
I keep coming back to that phrase in the garden, in the classroom, and honestly in life.
All flourishing is mutual.
What we grow, we grow together — with the soil, the insects, the water, the seasons, and each other.
Thank you for reading.
If you enjoyed this newsletter, please share it with someone who might like it.
Until next time,
Professor Brown
