Leichtag Commons, a nexus of sustainable agriculture, social enterprise, environmental education, and community engagement, all in the heart of scenic Encinitas, your neighborhood Gelson's Market, "Edible San Diego," Joe and Julie Walker, Jim and Judy Farley, and with the support of viewers like you.

Thank you.

♪♪♪ ♪♪♪ ♪♪♪ Nan Sterman: Botanic gardens are museums of living plants.

These gardens collect, study, teach, conserve, and display amazing and fascinating plants.

One of America's top-10 botanic gardens is right here in our own backyard.

San Diego Botanic Garden covers 37 acres in Encinitas, California.

It's an urban oasis with plants from around the world, some familiar and many exotic.

The garden's collections are organized into displays that illustrate the diversity of plants.

Nan: In most botanic gardens collections like these would be grown in a conservatory, or in a greenhouse, but here in Encinitas with the mild climate, the plants do just fine outdoors in the ground.

Nan: Thousands of people visit this garden every year to see the plants, to walk the trails, and to enjoy the garden's ocean view.

It's a fun and easy place for people to connect with plants and nature.

The earliest botanic gardens focused on medicinal plants.

Today, their work is far broader, based in science and nature.

From research and conservation, to horticulture and education, botanic gardens are places that link plants, people, and the planet.

Nan: We're at the San Diego Botanic Garden to enjoy the beautiful displays and appreciate the diversity of the collections, and we'll meet the team of professionals taking this garden into the future, today on "A Growing Passion."

♪♪♪ ♪♪♪ Nan: In the early 1940s, Ruth Baird Larabee acquired land on a ridge overlooking the Pacific Ocean in Encinitas, California.

She and husband Charles were an independently wealthy couple from Kansas City, who abandoned their privileged lives for a taste of adventure.

The couple was attracted to this slice of rural San Diego, with its perfect growing climate and rustic ranch house.

Here, they could enjoy their shared passions, which included gardening and exploring the Southwest.

The Larabees were early conservationists.

They developed a stunningly beautiful low-water landscape with more than 200 species of trees, shrubs, cacti, and succulents, many from Mexico and from South America.

They were also civic-minded people who welcomed scouts and other community groups to their gardens.

After the couple divorced, Ruth continued to live on the property until 1957, when she deeded it to the county of San Diego for a park and to preserve the habitat for native California quail.

The local horticulture community recognized the value of the Larabees' plant collection and the property's potential as a public garden.

After years of hard work, Quail Botanic Gardens, the original name, officially opened its gates to the public.

That was in 1970.

Since then, the garden has evolved from a small county park to a nationally recognized botanic garden, one of more than 600 nationwide and nearly 2,000 botanic gardens around the world.

They form a network to share and trade plants and research, to expand collections, and to conduct breeding programs.

In an era of rapid climate change, the work of botanic gardens is critically important.

Ari Novy: Yeah, so these cork oaks are just one of my favorite parts of the garden.

Nan: So, these date back to when the Larabees were here, right?

Ari: Absolutely.

Yeah, these are old cork oaks, and, I mean, this really lets you know--I mean, if you could go back in time on your property and do something 60 or 70 years ago, it would probably be planting some cork oaks.

Nan: Meet Ari Novy, president and CEO of the San Diego Botanic Garden.

He's a botanist and a researcher, with a passion for sharing his vast knowledge of plants.

Ari: I think of myself as an educator.

I happen to love plants.

I grew up around plants, and I was shocked to learn that plants are really important in the world.

They're not just pretty things.

And as I learned that and I realized that people care about plants, whether it's for aesthetic reasons or for economic reasons or for environmental reasons, that there was a place for somebody who really wanted to help educate people about plants.

Nan: Ari began his career on the East Coast, where he earned his PhD and traveled the world doing projects in conservation, sustainability, and invasive species, just to name a few.

In short time, he became executive director of the United States Botanic Garden in Washington, D.C. Ari: Plants are really important in everybody's lives, whether it's understanding where our food comes from, understanding how to steward our own yards, or understanding how our whole biosphere is really run by plants.

It's important that every regional and metropolitan center have a place where that can be fully explored.

Our region, and in particular North County, coastal San Diego, is what's often referred to by some of the horticulturists around as a Goldilocks zone.

It's just right, you know?

It's not too hot.

It's not too cold.

It's not too wet.

It's not too dry for growing a tremendous variety of plants.

And that makes it an amazing place to experiment with horticulture, but also an amazing place to be looking to conserve plants that maybe need special conditions to grow it.

Nan: Ari's been on the job just a few years, but with his fresh perspective the garden is expanding its direction and purpose.

Ari: Horticulture is integral to any botanic garden, and, unfortunately, horticulture often gets short shrift.

We don't spend enough time on the science and professional practice of the horticulture.

How do we get the plants to grow?

How can they be improved?

How can we protect them from diseases and pests and environmental challenges?

We often call that conservation horticulture.

It's applying the science of horticulture to the scientific goals of the botanic garden collection, and I couldn't think more strongly that that is the key to the success for all botanic gardens going through the next hundred years.

John Clements: Botanic gardens are changing.

They're ever-changing.

Nan: The man who heads the team that cares for the garden's living displays is horticulture manager John Clements.

John manages a crew that cares for more than 30 collections, from desert plants to tropical rain forest.

Today, John's touring me through the garden, starting with the newly renovated South Africa Garden.

Nan: John, South Africa looks like home.

John: It really does.

All of these plants are all over Encinitas.

Some people think they're natives here.

You know, they're great for us in Southern California because they're from a zone that is exactly like our weather, that wet winter and cool winters with dry summers, and so these plants move right in.

Nan: It's that classic Mediterranean, that band that's 30 degrees north and 30 degrees south of the equator.

That's where all those Mediterranean regions are, including us.

John: Exactly right, and so we can take those plants from the Mediterranean regions, plop them in here, and they just do beautifully.

And all these plants would be found in so many gardens in San Diego.

Nan: John, what amuses me is how there are so many so-common plants in here now, like the Natal plum and Euryops daisy and geraniums, and these plants come from South Africa.

People have no idea.

John: Yeah, they really are so common in our area.

You know, we've got Gazanias and fortnight lilies.

How about a jade plant?

There's nothing more common than that.

Nan: That's for sure.

You've taken all these plants that are really common in our landscapes, and you've put them together in a collection, and it's beautiful.

John: I think that's part of the secret of a good botanic garden, is it's not just a collection.

It's a collection that you wanna put in context and make aesthetically pleasing and beautiful and really make it a landscape garden.

Nan: Presenting plants as a beautiful composition achieves yet another goal.

It inspires home gardeners.

The variety of the shapes, colors, and textures helps visitors see how to use these very climate-appropriate plants in their own gardens.

Nan: John, this is one of the lesser common garden plants from South Africa.

This is Melianthus major, the honeybush.

You know, I love this.

When we were in South Africa a few years ago and we were driving out in the middle of nowhere, this was growing alongside the roads everywhere.

It's beautiful.

John: Yeah, this part of the South African Garden is more like our chaparral biome and a lot of the plants very similar, sages and things.

And this is one of my favorite plants.

That's Oxostylis alata, and it is so beautiful, and it needs to be grown more.

Gets beautiful red foliage several times a year and these really nice white flowers, and it's always transitioning from one thing to the next.

Nan: It's really pretty.

I love all these different sages.

They're so dry-growing, and they're just really well-suited for our gardens, too.

♪♪♪ Nan: This is a plant I would love to see growing in more home gardens.

This is a sage, a Salvia.

This one is africana-lutea from South Africa.

Incredibly drought tolerant.

It's got these gorgeous flowers.

I mean, you don't see that color very often, and the leaves are small and silvery, and they smell like the ocean.

Nan: We take a short walk to another collection that looks very familiar to California gardeners.

John: We're in Australia now.

Nan: That was a short trip.

John: Just up the hill.

Nan: I'm always amazed, because Australia is another Mediterranean climate, and yet it looks totally different.

John: Sure.

And no succulents.

No structures like the aloes with these very fleshy, water-retentive leaves.

These are all very tiny leaves.

Nan: Yeah, it's a different strategy for surviving hot, long, dry periods.

John: Yes, exactly.

Nan: Like California native plants, Australian natives deal with an arid climate and intense sunlight.

They, too, have evolved ways to minimize water loss.

Leathery leaves like those of the acacia have little water to lose.

Eucalyptus branches and leaves hang vertically.

That reduces the surface area exposed to the sun.

Other plants have silvery leaves that act like the shade in your car's windshield to reflect sunlight and prevent overheating.

Nan: What did you bring me?

John: I brought a blossom and a couple of branchlets from the Banksia integrifolia.

Nan: Oh, my goodness.

Look at how silver it is underneath.

John: It really is.

It's green on top, but the way that this plant orients itself, it will lay the branches out almost horizontally, with the silver exposed to the sun.

And so, it's reflecting a lot of that drying and intensifying heat.

Nan: That is such a cool tree.

John: They actually call that the bottle tree.

Nan: Juniper?

John: Yeah, it is.

There are some junipers from Australia.

Nan: I recognize this.

John: That's the Westringia.

Nan: Yep, coast rosemary.

This has really come into the landscape trade in a big way recently, hasn't it?

John: It really has.

You see it all over San Diego now.

Nan: Well, there is tall one.

Well, this is about as tall as they get, and short ones, and purple flower, and white flower, and the really great thing is they're tough as nails.

John: They are.

They're really easy to grow.

Nan: How many different varieties do you think you've got in the garden?

John: We probably have around 20.

Nan: What is this beauty?

John: This is a Streptocarpus.

It's commonly called the firewheel tree.

Nan: I can see why.

Look at those flowers.

It's like bright orange and bright yellow.

John: Yeah, it's great.

And, to me, they remind me of little flying saucers, little UFOs.

Nan: Like, they're just gonna swirl down?

John: Yes.

Nan: And the leaves are beautiful.

Look how big and green they are.

John: Yeah, it looks somewhat like an oak leaf.

Nan: Like an oak leaf, but also it reminds me of macadamia.

John: Yeah, it is.

They're both from Australia, and they're both in the Protea family.

Nan: I think we need to talk about eucalyptus.

John: Oh, that is a really tall rose gum.

Nan: How many different kinds of eucalyptus do you have in the garden, John?

John: We have about 20 species here.

Nan: And why do you have eucalyptus?

John: Well, in an Australian garden how could you represent the flora of Australia without a Eucalyptus?

Nan: Yeah, there's hundreds and hundreds of species of eucalyptus in Australia, and then all their relatives.

You know, it's really a shame that they've gotten such a bad rap here, because there are so many really wonderful useful ones.

But there are some that are really a problem in California.

John: Well, they've become invasive.

They volunteer too much, and they grow too fast here.

They actually do better here than they do in Australia.

Nan: And then, in a big rainstorm, if the ground gets saturated, they fall over and-- John: They are prone to falling over, too.

Nan: Eucalyptus were introduced to California more than a century ago as fast-growing wood for construction, windbreaks, and fuel.

While some species have created problems, these iconic trees are important to the garden's Australian collection, alongside Australian willows, Grevillea, and other eye-catching plants from the land down under.

San Diego Botanic Garden may be best known for its extensive bamboo collection, the largest and the oldest in North America.

Nan: John, how did this collection get started?

Do you know?

John: Yes.

This was a collection started back in 1979, and it was really started by a bunch of aficionados of bamboo.

And they founded the International Bamboo Society right here.

Nan: This nearly frost-free climate is perfect for this wide-ranging collection.

There are 121 kinds of bamboo growing here, native to Asia, the Himalayas, South America, and Africa.

Nan: Bamboo is a giant grass, right?

John: Nan, bamboo is definitely a giant grass.

In fact, just think of this entire acreage here as one giant lawn.

Nan: So, you have to water it like lawn.

John: We water it like lawn and we feed it like a lawn, so there are huge inputs of fertilizer.

And the sprinkling that happens here, the irrigation goes on all day four times a week to keep this looking good.

Nan: We know there's two kinds of bamboos, right?

John: There are two kinds of bamboo, Nan.

There are running bamboos and clumping bamboos, and all the horror stories you've heard about running bamboos are totally true.

Nan: So, this is a running bamboo.

I see this black line here.

Is this your attempt to keep it from running?

John: It is.

That is root barrier, and what we've done is we've buried 2 feet deep this root barrier that keeps the bamboo from reaching this perimeter, but it still does.

You can see in places that it wants to jump that root barrier and invade all the other space.

Nan: So, that's the one you really wanna be careful with.

John: You wanna be really careful with that one.

Nan: So, explain how the clumper grows.

It's different from the runner.

John: Right.

Whereas the runner has stolen and it travels and moves, this one really just emanates from one central growth point, so it grows very slowly and expands outward slowly.

Nan: So, you have, kind of, clumps.

John: Yes.

Nan: And if there's one that grows where you don't want it, you can just take it out?

John: It's very easy.

We just pop it out.

Nan: But what about all the leaves, John?

I mean, this is not, you know, neat-looking.

John: No, it isn't neat-looking, and it does create a frightful mess, but we leave the leaves around the bamboo's clumps themselves because it helps to recycle the nutrients that are left in the leaves, and it also helps us to save some water.

And the leaves also contain silica, and the silica will then be uptaken by the bamboo.

It makes it strong.

Nan: But I probably don't want this in my backyard.

John: You don't want this in your backyard at all.

Nan: But I like it in the botanic garden.

That's the place to see it.

John: That is the place to see it, where people don't have to do the work.

Nan: But you do.

John: But we do.

Nan: The variety of bamboos is enormous.

Some come from the tropics, others grow where it snows.

Some have stalks as narrow as a drinking straw and others almost as wide as trees.

The diversity in their height, shape, color, and form is amazing, as is the wide variety of uses for this giant grass.

Nan: So, this is a good example for using bamboo for construction, huh?

John: It is, indeed.

Nan: Bamboo, it just--you know, it's so hard, and I know it's really strong.

John: It is.

It's stronger than hardwood.

Nan: Wow.

No wonder it's such a popular construction material.

John: Yeah, all over the world.

Nan: This is the famous timber bamboo, right?

John: This is the famous timber bamboo.

This is Dendrocalamus gigantea.

You get an idea from the name how big this will be.

Nan: Gigantea.

John: Gigantea.

Nan: This is the one used for construction?

John: It is used for construction.

Nan: And I'm holding what part?

John: That's the base, so that's where the roots came from.

Nan: The roots were here.

John: They were there.

Nan: And this was-- John: And that was attached.

I've just cut it to show what the bottom looked like, but this would have been about three times longer than this on a large-size plant.

Nan: So, look how thick the walls of these timbers are.

This is why this is used for construction.

What about the one behind us?

John: This is a young one.

Our other one died off.

Bamboo do cessate.

They all die at once, and so this had to be replaced, but it's a very junior giant bamboo.

Nan: A junior giant.

I love that.

Nan: This collection captures so many aspects of these amazing plants: their botanical variety and their origins, their aesthetic value, their long history of human use, and their cultural significance.

This is classic botanic garden.

Nan: I think this is one of the more picturesque parts of the garden.

John: It is definitely picturesque, and this is a spot where a lotta people take photographs.

Nan: The Mexico collection has its roots with the Larabees.

They started this garden from seeds and plants collected on their travels around Mexico in the southwest.

The topiaries are far more recent.

They were made for a display at the San Diego County Fair several years ago.

These days, they're lovingly cared for by volunteers.

Nan: These big trees aren't exactly from Mexico.

John: No, not exactly.

They're from China.

Nan: After a day of walking the garden, this is an inviting space to rest and to reflect on the evolving nature of garden displays, this one in particular.

John: You know, we often say in the gardening business that a garden is always changing, that it's never really arrived.

Well, a lot of the plants that are here preexisted being in Mexican Garden.

We have an Australian bottlebrush, some Chinese junipers, other trees from China, and they are very old.

They were planted by the Larabees, and so they really are trees we don't wanna cut down yet.

But as they pass away and things need to be taken out, this garden will eventually contain all Mexican plants as we move forward.

Nan: Since botanic gardens are living collections, change is inevitable.

While the garden honors its heritage, its dedicated horticulturists are always expanding its collections along with its mission to educate, entertain, and inspire.

Nan: The Dickinson Family Education Conservatory is the newest exhibit at the San Diego Botanic Garden.

The 8,000-square-foot glass house is a unique blend of educational facility, public space, and display of rare and unusual tropical plants.

Nan: Tony, everywhere else in this garden plants grow in the ground.

What does the conservatory allow you to do that's different from the plants growing in the ground?

Tony Gurnoe: This has allowed us to push our collection into the world of truly tropical plants.

San Diego is pretty privileged in outdoor weather as is.

It's subtropical climate.

We can get away with a lot outdoors, and that's part of why it took us so long to get around to this, but with this little bit of an embellished environment we can grow things that are truly tropical and represent a whole new group of plants from around the world.

Nan: The plants look amazing.

What do you have to do?

How do you have to modify the environment to support these plants?

Tony: Fortunately, not as much as you might expect.

Encinitas is a very wonderful place to be growing things.

What we need to do is to provide a little bit of an enhanced humidity throughout the year, especially during our dry late-summer season.

And then, over winter just a touch of heat, which actually comes from the radiant heated floor below us.

Nan: What other technology is in the space?

Tony: We have sensors both hanging and at the ground level that help us monitor things like humidity and light levels.

We have a computer-programmable system that allows us to use shade, high-pressure foggers overhead, as well, as I mentioned, the heating in the floor to keep this place within, kind of, an ideal humidity and temperature range not only for the plants, but for the people that inhabit it, as well.

Nan: Here collections are displayed in an ingenious system of floating plant islands that raise and lower to allow visitors a close-up look at the plants.

Nan: This is one of the coolest things I've ever seen, Tony.

I've been in a lot of botanic gardens.

I've never seen anything like this.

Tony: This is our best effort at recreating just a piece of the tropical canopy and bringing it down right here.

Usually, the stuff will be a hundred feet in the air.

Nan: So, when you say bring it down, what do you mean by that?

Tony: I mean that these are mobile.

As they stand here you get an up-close experience with the plants, but if we need to use this space for other purposes they actually go up to canopy level, just like they would be overhead in habitat.

Nan: These displays are a collaborative effort of the garden's horticulture team, using plants already in the collection, others from local resources, and some from other botanic gardens.

Nan: These are not plants that we grow in soil in the ground.

These are plants that would grow on a tree, right?

Tony: We strategically picked plants from a type of group called epiphytes, those plants that do grow on other plants naturally.

Nan: So that's why it all works, but it's not one kinda plant.

I mean, I see bromeliads, and I see ferns, and I see orchids, and all kinds of things.

Tony: It happens to be that that same group, the epiphytes, represent some of the most diverse plant families and genera in the entire world, so we have quite a lot to choose from.

Nan: Okay, what's the most unusual plant?

Tony: The most unusual plant is probably that big-leafed anthurium from-- So, a lot of what we have in here is chosen for its ornamental value, but some of what we have tucked in here is legitimately rare in worldwide conservation terms.

Nan: The conservatory's climate-controlled environment allows the garden to expand its collections and help meet its mission to conserve rare and endangered plants and to educate the public about that work.

Nan: Wow.

Nan: The conservatory is fascinating, with its plant islands, its hanging plant chandeliers, and a 15-foot tall living wall, all of which are possible with just small modifications to the temperate coastal climate that drew the Larabees here in the first place.

Nan: Tony, it's amazing that you can just open this up.

This is, sort of, the epitome of California indoor-outdoor living, but for plants.

Tony: We wanted as much as possible to dissolve the perceived boundary between indoors and outdoors, as well as to bring some of the same plant motifs and interpretation out into the landscape as much as the plants and our weather will allow.

Nan: You did it really well.

It's really lovely.

Nan: Connecting people to plants and helping us enjoy, learn, and value the flora that makes life possible, the San Diego Botanic Garden is a pleasure and a treasure we all enjoy.

Nan: Connect with us at "A Growing Passion" for garden tips, behind-the-scenes updates, and to see what's growing in California.

Watch all of our shows online any time at AGrowingPassion.com.

Nan: Gardens like this celebrate the diversity of life.

They show us how plants in our world are endlessly fascinating.

I'm Nan Sterman.

See you next time.

♪♪♪ ♪♪♪ ♪♪♪ ♪♪♪ announcer: Support for this program comes from the KPBS Explore Local Content fund.

Supporting new ideas and programs for San Diego.