Professor Maple's Secret Garden news letter.

[professormaplesgarden]

🌿 Professor Maple’s Secret Garden 🌿

Field notes, garden questions, and occasional botanical opinions nobody asked for.

August 8

Hello, fellow plant nerds.

August has arrived, which means some gardens are reaching their glorious peak and others are beginning to look as though they've been left unattended during a minor apocalypse.

Both are perfectly normal.

This week's mailbag includes a shy gardener from Southern California contemplating several pots of abandoned tomato soil, and a gentleman in Seattle apparently planning to turn his balcony into a Pacific Northwest berry patch.

But first, I've been spending quite a bit of time in the field lately, and one little plant keeps demanding my attention.

So this week's Plant of the Week comes straight from my research notebook.

🌸 Plant of the Week: Pink Sand Verbena

Abronia umbellata

Pink Sand Verbena is one of those plants you could easily walk past without realizing you're looking at something extraordinary.

It grows low against the sand along the Pacific coast, producing clusters of wonderfully bright pink to purple flowers above thick, slightly succulent leaves. It's adapted to a world that isn't particularly hospitable: shifting sand, salt spray, strong winds, summer drought, and very little shelter.

And yet it blooms.

That alone would earn my admiration.

But Pink Sand Verbena is also a reminder of why coastal plant conservation matters. Populations have declined or disappeared from portions of their historic range as dune habitats have been altered by development, recreation, invasive plants, and other disturbances.

When botanists study plants like this, we're not merely counting flowers. We're trying to understand an entire ecological relationship. What allows a population to persist? How are its seeds dispersed? Which insects visit the flowers? What happens when the surrounding dune community changes?

Sometimes protecting a species begins with something wonderfully unglamorous:

Standing in the sand with muddy knees, a notebook, and absolutely no idea where you left your coffee.

Occupational hazard.

Now, on to your questions.

---

✉️ Anonymous from San Diego, California, Zone 10b

"Hi Professor Maple,

I'm sorry about being anonymous. I'm feeling shy today.

Anyway, tomato season is officially over, for me anyway. The August heat is too much. What should I do with my unused pots with soil from my removed tomato plants? Should I continue to keep them watered until fall? Or is it okay to just let them dry out until I'm ready to use them again?

Thank you,

Anonymous"

Dear Anonymous,

First, you're perfectly welcome to be shy in the Secret Garden. No identification required. Sunglasses and a large floppy hat are optional.

And yes, you can let those pots dry out.

If there's nothing actively growing in them, there's generally no reason to spend water keeping bare potting soil moist through a hot Southern California August.

Remove the old tomato roots and any fallen leaves or fruit. If the plants had serious disease problems, that's a slightly different conversation, and depending on the disease I might recommend replacing some or all of the potting mix rather than immediately reusing it.

Otherwise, let the pots rest.

Before planting again in fall, loosen the soil because container mix can become compacted. Check that the drainage holes haven't become blocked. Then refresh the old mix with some new potting soil and compost or another appropriate organic amendment.

One important distinction: reusing potting mix is fine; expecting exhausted potting mix to behave like brand-new soil isn't.

Your tomatoes have been dining there for months. They've taken nutrients with them.

Think of fall as checking the room after particularly demanding houseguests have departed.

Open the windows.

Fluff the pillows.

Restock the refrigerator.

And invite somebody new.

So go ahead, Anonymous. Stop watering those empty pots.

You have Professor Maple's official permission to neglect them.

Enjoy it while it lasts.

---

✉️ Franklin from Seattle, Washington

"Hi. Is it possible to grow blackberries and Salmon Berries on my balcony in Seattle?

Love,

Franklin"

Dear Franklin,

I don't usually receive gardening questions signed "Love," but I'm choosing to believe we've reached that stage in our relationship.

And yes...with qualifications.

Blackberries are certainly possible in containers. But choose carefully.

A full-size trailing blackberry on a balcony can quickly stop being a plant and become a territorial dispute.

Look for a compact or container-suitable variety. Give it the largest container you can reasonably accommodate, excellent drainage, plenty of sun, and sturdy support. Blackberries are hungry plants, so they'll also need regular feeding and consistent moisture during the growing season.

Now, salmonberry is where Professor Maple becomes slightly less encouraging.

Rubus spectabilis is a magnificent Pacific Northwest native, and Seattle's climate certainly suits it. But salmonberry naturally grows into a substantial thicket-forming shrub and spreads by underground rhizomes.

In other words, Franklin, salmonberry has ambitions.

You could experiment with one in a very large container, particularly if your balcony gets some afternoon shade and you can keep the soil consistently moist. But I wouldn't choose it as my first balcony berry.

If your heart is set on growing native berries, consider looking into smaller Pacific Northwest species that are better suited to containers.

Or grow the blackberry on your balcony...

…and visit your salmonberries in the forest.

Sometimes loving a plant doesn't mean bringing it home.

Sometimes it means knowing where it belongs.

---

That's it from the Secret Garden this week.

I'm headed back into the field, where somewhere along the Pacific coast a tiny pink flower is growing in terrible soil, being blasted by wind and salt, and somehow managing to look fabulous.

Frankly, I find that encouraging.

Until next week, fellow plant nerds:

🌱 Let the empty pots rest.

🫐 Keep ambitious berries under supervision.

🌸 And never underestimate a little plant growing in a difficult place.

Happy gardening,

Professor Maple

"Grow what you can. Protect what you can't. And for heaven's sake, remember where you put your coffee." ☕🌿

[professormaplesgarden]

Different format today. Let me know which you like better. If you have a gardening question please ask.

Happy 4th of July to all the plant nerds south of the border.

[professormaplesgarden]

🌿 Professor Maple's Secret Garden 🌿

A little corner of Tumblr where plants, people, and curiosity grow together.

This Week's Entry

Good morning, fellow plant nerds.

I'm changing things up this week. Normally I'd introduce a favorite plant before opening the mailbag, but one question landed in my inbox that has been sitting with me all week. I suspect many of us have felt something similar, whether we care for houseplants, vegetable gardens, or an entire landscape.

So today, let's begin there.

✉️ Reader Mail

Jack from Los Angeles writes:

"Hello, Professor Maple. First off, I have to say that I like your blog. You should post more often.

My question is less about gardening and maybe more about relationships. Well...I had two tomatoes and a pepper plant growing on my balcony here in LA. I was gone for a few days and when I got back all three plants were dead. OK, the truth is, when I got home I kind of forgot to check them, so in total they went about a week without water.

Anyway, I feel awful. I don't even care if I had ever gotten any tomatoes or peppers. I'm the one who brought them here and now I neglected them. I feel like I should just give up.

- Jack"

Hello, Jack.

First, thank you for your kind words.

Second...Don't give up, your tomatoes deserved another chance and so do you.

Every gardener, from the person with one basil plant on an apartment windowsill to someone managing acres of farmland, has killed plants.

Sometimes it's frost, sometimes insects, sometimes disease. Sometimes life simply gets busy. And sometimes...we forget to water.

The fact that you feel guilty tells me something important.

You weren't growing tomatoes because you wanted vegetables.

You were caring for another living thing.

That feeling of responsibility is one of the quiet gifts gardening gives us. Plants ask almost nothing from us. They don't care about our careers, our income, our mistakes, or whether we've had a productive week. They simply ask for sunlight, water, and a little attention.

Sometimes we fail them. But failure is part of becoming a gardener.

If every plant survived, we'd never learn when to water, when to prune, when to transplant, or when to simply laugh and try again.

I'll tell you a secret. I'm a botany professor. I've killed more plants than most people have ever owned.

Some by accident, but some through neglect and some because I was convinced I knew better than the plant.

The difference between a gardener and someone who used to garden isn't talent. It's that the gardener plants another seed.

So here's your assignment. Go buy one new tomato and one new pepper. Bring them home and water them today.

Then forgive yourself because the garden already has.

🌸 Plant of the Week: Salmonberry

(Rubus spectabilis)

There are some plants that demand attention and then there are plants that quietly belong exactly where they are.

Salmonberry is one of those plants. If you've walked through the coastal rainforests of the Pacific Northwest in spring, you've probably seen its brilliant magenta flowers lighting up the forest edge long before summer arrives. By early summer those flowers become berries that range from translucent golden-orange to deep raspberry red. Every berry seems to have its own opinion about what color it should be.

Humans aren't the only ones who appreciate them. Birds, bears, small mammals, insects, and countless other forest creatures all make use of salmonberry. It is one of those wonderful native plants that supports an entire community rather than simply decorating a garden.

The berries themselves are delicate, lightly sweet, and often surprisingly subtle compared to raspberries or blackberries. Some are wonderfully flavorful. Others taste mostly of sunshine and rainwater. That's part of their charm. They refuse to become factory fruit.

I think that's why I love them.

Salmonberries remind us that not everything in nature exists to maximize production. Some plants simply invite us to slow down, wander a forest trail, and enjoy whatever gifts happen to be ripe that morning.

Thank you for spending a few quiet minutes with me this week.

Until next time...

🌱 Water your plants. 🌸 Forgive your mistakes. 🐝 And remember that every experienced gardener was once a beginner standing over a wilted tomato wondering what went wrong.

Happy gardening,

Professor Maple

"May your compost stay warm, your weeds stay humble, and your curiosity never stop growing."

[professormaplesgarden]

🌿 Professor Maple's Plant of the Week 🌿

The Secret Garden Newsletter

By Professor Maple. June 21, 2026

Hello fellow plant nerds,

The fog was hanging low over Tofino this morning as I wandered through the herb garden with a cup of coffee in one hand and a notebook in the other. The bumblebees were already hard at work, which brings me to this week's featured plant.

🌸 Plant of the Week: Anise Hyssop

(Agastache foeniculum)

If I were stranded on a gardening island and allowed only one ornamental herb, Anise Hyssop might very well be my choice.

Native to portions of the northern Great Plains and Upper Midwest of North America, this member of the mint family combines beauty, fragrance, wildlife value, and culinary usefulness into one remarkably easy-going plant. The leaves release a sweet aroma reminiscent of licorice, fennel, and root beer when crushed. Even people who claim they "don't like licorice" often find themselves sneaking another sniff.

The flowers bloom for weeks during summer, producing elegant lavender-purple spikes that attract an astonishing variety of pollinators. Bumblebees adore it. Honeybees adore it. Native solitary bees adore it. Hummingbirds frequently stop by as well. During peak bloom the plant can seem less like a flower and more like a tiny airport with constant arrivals and departures.

In the kitchen, the leaves can be used fresh in teas, fruit salads, or desserts. I often add a few leaves to iced tea during the warmer months. In the garden, it asks for very little beyond sunshine and reasonably well-drained soil. It survives cold prairie winters, tolerates summer heat surprisingly well, and often self-seeds politely enough to provide pleasant surprises the following spring.

In short: beautiful, useful, fragrant, pollinator-friendly, and almost embarrassingly easy to grow.

A professor's dream plant.

Reader Mail

✉️ Jake from Boston, Massachusetts asks:

"Dear Professor, is it possible to grow a mango tree in the suburbs of Boston?"

Hello Jake,

Technically yes.

Realistically... you'll need to convince the tree that Boston is somewhere near Miami.

Mangoes are tropical trees that dislike frost about as much as I dislike faculty budget meetings. Outdoors, a Boston winter would end the experiment very quickly.

Your best option is growing a mango in a large container that spends summer outdoors and winters indoors in a bright sunroom, greenhouse, or very sunny window. Plenty of people grow mangoes as houseplants. Producing fruit is more challenging, but not impossible if you have enough light and patience.

Think of it as growing a tropical vacation rather than a tree.

✉️ Sarah from Phoenix, Arizona asks:

"Can I grow tomatoes in Phoenix during the summer?"

Hello Sarah,

Growing tomatoes through a Phoenix summer is a bit like asking a marathon runner to compete while standing inside a pizza oven.

Many tomato varieties struggle when daytime temperatures remain above 95°F (35°C). Pollination decreases, flowers drop, and fruit production slows dramatically.

Most Arizona gardeners plant tomatoes in late winter or very early spring and harvest before the most intense heat arrives. Some gardeners also grow a fall crop that begins when temperatures start easing.

If you're determined to try summer tomatoes, provide afternoon shade, deep mulch, consistent watering, and choose heat-tolerant varieties. Even then, expect the plants to spend July and August questioning their life choices.

✉️ David from San Diego, California asks:

"Hi Professor Maple, I have a rat problem in my garden but I also have a dilemma. I hate the idea that these critters are stealing tomatoes and biting my peppers, but I don't want to hurt them. What should I do?"

Hello David,

As someone who has spent many evenings negotiating with garden thieves of various species, I sympathize.

The good news is that you don't need to choose between feeding the rats and harming them.

Start by reducing temptation. Harvest tomatoes as soon as they begin showing color and allow them to finish ripening indoors. Remove fallen fruit and garden debris that provide food and shelter.

Physical barriers are often the most effective solution. Individual fruit bags, wire mesh cages, hardware cloth, or netted enclosures can protect prized crops without injuring wildlife.

You can also make the garden less attractive by limiting water sources at night and trimming dense vegetation where rodents hide.

One thing I strongly discourage is poison. Aside from ethical concerns, poisoned rats are often eaten by owls, hawks, coyotes, snakes, and neighborhood cats. The poison can move through the food web in unfortunate ways.

Remember: the rats aren't plotting against you. They're simply convinced that your garden is a very successful restaurant.

Your challenge is convincing them that reservations are no longer available.

That's all for this week.

Now if you'll excuse me, there's a cup of coffee getting cold beside a patch of Anise Hyssop, and I suspect several bumblebees are judging my productivity.

Until next week, fellow plant nerds:

🌱 Keep your soil healthy.

🌸 Keep your curiosity growing.

🐝 And always leave room in the garden for something that makes the bees happy.

Happy gardening,

Professor Maple

"Cultivating plants, curiosity, and occasional chaos since 1977."