People need plants. They are the root cause of our health, habitat, and happiness. More than ever, plants need you. Join us this fall as we explore how cultivating deeper connections with plants can grow a brighter tomorrow for our ecosystems and communities.

Think of your happy place—a location or memory that you recall fondly—and I bet plants are in the picture. Maybe they define the surroundings of a cherished moment. Maybe they’re on the plates of a meal shared with loved ones. Maybe plants are your happy place: a beloved tree, garden, or landscape that fills you with joy. The root cause of happiness, it turns out, is often plants. 

Hawaiian lei are the epitome of plant joy. A master lei maker is a matchmaker. With devotion, the lei maker weaves together the right plants for the right person. Some lei, like those crafted with hundreds of ʻilima or kou blossoms, are a labor of love. As the soon-to-be-recipient of the lei dreams in the quiet dawn, hundreds of petals are gathered. As the recipient begins to wake, hands begin to weave the lei together, each blossom strung with utmost care. As the recipient’s day progresses hour by hour, the lei grows flower by flower. At just the right moment, the lei maker and the recipient come together. The gift that is given is a pure expression of aloha. The lei encircles them in a love that only the lei maker, and the specific harmony of woven plants, can provide. It is hard to imagine a smile bigger, a smile warmer than when one receives a lei. 

Plants make us happy, everywhere. Remarkably, it seems that plants help us express our most human emotions. Gifts of flowers, like lei, are a timeless way to communicate our deepest feelings. Indeed, plants guide many of our cultural and spiritual practices. Hula, a revered dance described by King David Kalākaua as the “heartbeat of the Hawaiian people,” is inextricably rooted to the plants of Hawaii. Plants can be both muse and material. In addition to representing plants in virtually every media, artists throughout time have drawn, painted, woven, sculpted, carved, and dyed with plants. Without plants, the world would be lifeless in many definitions of the word. Across tropical regions and throughout the world, plants make life happier. 

Ties that bind

Watching Lei Wann, Director of Limahuli Garden & Preserve, make lei is as mesmerizing as the beautiful plants she uses. Her hands know each flower, frond, fruit, and seed on a profound level. “For me, many plants have deeper connections to my heritage and culture. Being with them or working with them is like being with an ancestor. It’s like being with family.” 

Her lei braids together generations of people and plants. Woven into every lei is a heritage of the artform itself as well as the moʻolelo (stories) behind each plant. Like the cord that holds the lei together, an inseparable connection to the ‘āina (land) threads everything together. Her intimate knowledge of plants, and their inherent meanings, guides her process as she makes lei for friends new and old. 

“For me, plants have deeper connections to my heritage and culture. Being with them or working with them is like being with an ancestor. It’s like being with family.”

Lei Wann, Director of Limahuli Garden & Preserve

Lei loves to teach traditional plant practices like lei making. “By teaching these plant practices, I am keeping my culture and traditions alive. When you engage in plant practices, you are making deep connections with plants. You are interacting with them and getting to know them on a deeper level.” Nurturing community connection to the ‘āina is a key part of Limahuli’s approach for restoration. Lei leads the stewardship of Limahuli Valley and Preserve with an ahupuaʻa frame of mind: that ecosystem restoration is fundamentally tied to community restoration. 

Two of Lei’s favorite plants are laua’e o Makana and pāpala. “For generations, these plants were used to reference our place and people. Laua’e can also be a metaphorical way of speaking of the sweet and cherished people of Haena. Pāpala is part of the famous art of ʻōahi (fire throwing ceremony) of which my ancestors were famous. Pāpala can also metaphorically speak of love and aloha.” Revitalizing plants revitalizes culture. Laua’e and pāpala, among many other invaluable plants, are grown at Limahuli to ensure that ancestral traditions continue. 

As family members, as gift givers, as culture keepers, plants make Lei happy. “They bring life and goodness into the world, and for that I am humbled and happy to be in their presence.” 

Growing happiness

For NTBG volunteer Leslie Ridpath, gardening is a wellspring of joy and restoration. “I find that my garden gives me a creative outlet. I really enjoy using the color and structure of the plants in a variety of combinations creating different distinct areas. Unlike a painting, there is constant change in a garden.” 

When Leslie relocated to Kauai, she began volunteering at NTBG to “learn about the plants that do well in this environment to help me in designing my own garden.” By volunteering across departments, she drew connections between cultivating plants and making a positive impact for our local environment.  “I love to learn new things and as I have volunteered in various roles at NTBG, it has really helped to get the bigger picture of what they are trying to accomplish in their mission. By volunteering at NTBG, I’ve had the chance to work with endangered plants, including a study that looks at the impacts of climate change on coastal plants. I find this very rewarding.”

Plants provide Leslie with the inspiration and opportunity to make a difference in her community. By growing plants native to your region, you can too! Native plants provide a refuge for wildlife, are environmentally friendly, and celebrate the beauty unique to your home. For Leslie, growing plants in her garden and as a volunteer at NTBG provides a perennial source of happiness. 

Spreading the love

So much happiness is rooted in plants. They nourish our bodies and feed our souls. They tie generations together, keeping culture alive. Plants also help us share the love. By growing plants, we can cultivate a better world for our families, communities, and ecosystems. What could bring more joy than that? 

Free Downloadable Tropical Plant Coloring Books

Learn more about tropical food plants, Hawaiian culture, and our islands’ unique ecosystems with our new coloring books! Click the images below to download a printable PDF. Each coloring book features beautiful drawings of tropical plants coupled with fun facts, sure to please plant lovers of any age.

About the National Tropical Botanical Garden

Did you enjoy these coloring books? Consider supporting tropical plants through a donation today.

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People need plants. They are the root cause of our health, habitat, and happiness. More than ever, plants need you. Join us this fall as we explore how cultivating deeper connections with plants can grow a brighter tomorrow for our ecosystems and communities.

Our homes and habitats are made possible by healthy plant communities

Where are you at this moment? Whether you’re surrounded by wildlife or citylife, you’re in a habitat that is alive with relationships. Species and soil, climate and community, wind and water are working together to make life possible. A Hawaiian proverb reads I ola ‘oe, i ola mākou nei. “My life is dependent on yours, your life is dependent on mine.” Everything in your habitat is intimately connected.

In many ways, plants are the threads that weave this tapestry together. They stitch together entire food webs and provide a patchwork of so many other necessities, down to the very air we breathe. However, in a rapidly changing world, plants and plant communities are disappearing. Each plant lost is a thread cut from this vibrant tapestry, an end to a network of relationships and a potentially reshaped habitat. To restore habitats, it’s vital to rethread them with their unique plants that are a support system for the life they sustain. 

Plants are a habitat’s best friend

At this moment, there is a good chance that Uma Nagendra is in the habitats of Limahuli Garden & Preserve. As the Conservation Operations Manager there, she works to understand and restore Hawaiian ecosystems in the face of constant change. Limahuli on Kauai is considered one of the most biodiverse valleys in Hawaii. To perpetuate the environmental integrity of this invaluable place, Uma relies on plants. “Plants are the foundation of nearly every ecosystem – they don’t just enhance the ecosystem, they create it!” shares Uma. “Here in Hawaii, ohia and other montane trees capture mist from the clouds and gather raindrops, forming the cloud forest that feeds all the rest of Hawaiian streams. Their nectar feeds the forest birds; their bark houses mosses, insects, and snails; their roots shelter seabird burrows.” 

Limahuli Garden and Preserve totals over 1,000 acres and are managed within an ahupuaa framework, continuing a living legacy of indigenous stewardship. Ahupuaa are Hawaiian land divisions that extend from mauka (mountain) to makai (ocean). Within this framework, humanity and nature are inseparable. The same water that condenses atop the highest ohia in the ahupuaa makes its way through misty falls and mesic forests, through loi kalo (taro terraces) and rushing streams out into a bustling reef. At every section of the ahupuaa, plants sustain life for the ecosystem and community alike. 

On a daily basis, Uma experiences the biodiversity that plants make possible in Limahuli’s preserves: Tiny land snails sneaking by on haha (Cyanea spp.) leaves, pueo owls in courtship, Tetragnatha spiders in “full arachnid-yoga poses,” apapane birds diving across the ohia canopy, the barking sounds of ao (Newell’s shearwater), hundreds of opae kuahiwi (mountain shrimp) darting in the stream. All of these precious residents of Limahuli depend on the ahupuaa’s native plants. Without them, Limahuli wouldn’t be the same. “A forest in Hawaii dominated by invasive guava will feel completely different from a diverse ohia forest,” says Uma. “In the ohia forest, you’ll see a wider variety of textures and layers, you’ll feel the moisture hanging in the air, you’ll feel the spongy moss cover beneath your feet, perhaps you’ll even hear more birds and other animals enjoying the trees. Because plants are the foundation for everything else, it truly matters which plants are the ones building that foundation.” 

“We can all do our part to make sure our habitats have the support system they need.”

Uma Nagendra, Conservation Operations Manager

Uma and her team work to safeguard and restore the habitats of Limahuli. You can help be the support system for the habitat you call home. “We can all do our part to make sure our habitats have the support system they need by limiting the impact of existing invasive plants, animals, and microbes; avoiding introducing new ones when we enter wild places; and not exacerbating climate change.” Find out what invasive species are impacting your habitat and what native plants share your home. Building awareness and knowledge about the plants that define your habitat is a great step towards caring for the special place you live.

To help us root more deeply into the habitats that support us, Uma recommends a recurring meditation. “Find a quiet moment where you can observe your outdoor surroundings. It doesn’t matter if you’re in an urban environment, rural, suburban, or wilderness – all of these are ecosystems. Try for 15 seconds of stillness, then observe with as many senses as you can. Do you hear or see any animals or plants? What textures, air currents, warmth, or precipitation is present? Repeat the exercise weekly. Can you notice when the seasons begin to change? What animals and plants are active or migrating at different times of the year? Does the air feel different to you as the months roll on?”

Hope for plants means hope for habitat

Seana Walsh, NTBG’s Conservation Biologist, has been growing a brighter tomorrow for the beloved alula (Brighamia insignis) for over seven years.  While extinct in the wild, these charismatic plants that once adorned sea cliffs on Kauai and Niihau have made their way across the world in botanical garden collections and as indoor houseplants. Seana is leading a cutting-edge study to strategically breed these cultivated alula to enhance diversity and plant health. While this strategy has been used in zoos for decades, this major undertaking is one of the first of its kind for plants. Seana’s work with alula is perpetuating a beloved plant for Hawaii. At the same time, she is helping to develop and inform strategies for perpetuating plants—and the habitats they sustain— across the world. 

For Seana, bringing plants back from the edge of extinction is a moral obligation. She grew up on the leeward side of Maui, where invasive species and degraded landscapes provided a stark comparison to the native plants and habitats she now nurtures. “Knowing what I know now, and what I experience during my time and work in the forest, it is very clear how different a healthy, native forest both looks and feels compared to one dominated by non-native species,” Seana says. “In a healthy native forest, you won’t see large areas of bare soil or pooling water. Non-native forests with exposed earth cause runoff when it rains and pools of water which are breeding grounds for mosquitoes, a huge threat to our native forest birds. A native forest results in less runoff which equates to more groundwater recharge and less sediments flowing downstream and covering our reefs.”

Plants make home, home

Healthy habitats and communities rely on plants. By tuning in to the habitats we call home and the plants that define them, we can learn how to be a support system for the places we love.

Everyone can have an impact on #GivingTuesday! Join NTBG on November 29 by pledging your time, skills, voice, or dollars to grow a brighter tomorrow for the tropical plants that sustain and nourish us all. Add Giving Tuesday to your calendar and be sure to follow us on social media!

Five Ways to Give on GivingTuesday

This holiday season, celebrate the tastes of the tropics wherever you are with breadfruit! Here we feature chef Nikki Gold’s incredible ulu cheese casserole recipe, the dish that scored 1st place at our annual Ulu Cook-off on Maui. We also share preparation tips, additional recipes, and resources for finding breadfruit near you.

“Ulu is such a wonderful and special fruit that when I cook with it, I feel like I am honoring a part of Hawaiian culture. I mean, it is such a beautifully versatile fruit how could I not love cooking with it?

My inspiration for the ulu casserole this year came from my daughter. She loves a particular movie about a rodent chef who makes a casserole that melts the heart of a critic. Like the little rodent, my daughter loves helping me in the kitchen. This casserole was inspired by her using all of her favorite flavors in our kitchen. Ulu, Okinawan sweet potatoes, carrots, and cheese.“

Nikki Gold, chef and 1st place winner of the 2022 Ulu Cook-off

Share your completed dishes with us on social media and tag us @ntbg on Instagram.

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Ulu Cheese Casserole Recipe

Cooking Instructions

Step 1

Heat oven to 375℉. Brush the inside of a 10 inch cast-iron skillet with olive oil.

Step 2

In a large bowl, combine ulu, potato, carrots, onion, herbs, salt, pepper, and 90% of the cheese. Mix until everything is evenly coated.

Step 3

Layer thin sliced vegetables upright in the skillet until full. Sprinkle it with remaining cheese. Pour milk and broth over vegetables and cover with tinfoil to seal edges.

Step 4

Bake for 50 minutes and remove foil, continue baking for 15-20 minutes until breadfruit is tender and slightly browned. 

Share your completed dishes with us on social media! Be sure to tag @ntbg on Instagram.

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Breadfruit History

The trees are traditionally used and are a major component in mixed cropping agroforestry systems. Breadfruit creates a lush overstory that shelters a myriad of useful plants including yams, kava, noni, bananas, and sweet potatoes.

One of the highlights of the McBryde Garden is NTBG’s Regenerative Organic Breadfruit Agroforestry (ROBA) project which acts as a living classroom and 2-acre demonstration project. The data that is collected by our ROBA team is used to advise local farmers on best practices and techniques. This year, our team was able to ground proof ROBA’s productivity and display breadfruit agroforestry’s ability to support community resilience in times of need. So far, over 6,000 lbs. of breadfruit has been donated to local food banks on Kauai!

Additional Breadfruit Resources and Recipes

Community Supported Agriculture

Wondering how to sign up for a Community Supported Agriculture (CSA) subscription or where you can buy breadfruit in Hawaii? Check out the links below to find a source near you.

People need plants. They are the root cause of our health, habitat, and happiness. More than ever, plants need you. Join us this fall as we explore how cultivating deeper connections with plants can grow a brighter tomorrow for our ecosystems and communities.

If you haven’t thought about plants today, you’re certainly not alone. Even though plants make our everyday possible, many of us seldom pause to appreciate just how important they are to our health and overall wellbeing. Plants and people go together. In the Hawaiian worldview, kalo (taro) is an older sibling who continues to feed and nourish communities across the islands. Ola ke kalo, ola ke kānaka; ola ke kānaka, ola ke kalo is a Hawaiian proverb that means if kalo lives, Hawaiians live; if Hawaiians live, kalo lives. 

“In some Native languages, the term for plants translates to ‘those who take care of us,’” says Potawatomi botanist and Braiding Sweetgrass author, Robin Wall Kimmerer. From lowering stress and anxiety, to producing cancer-fighting compounds and healthy regenerative agriculture systems, plants are often our best teacher and most helpful remedy. Increasing our awareness and recognition of plants is the first step in protecting our precious biodiversity. Our future depends on it.

Becoming Plant Passionate

Plants feed, shelter, heal, and fuel us. They inspire art, help us express emotion, and guide many of our cultural and spiritual practices. Data also shows that spending time in nature improves our mental and physical health. So, why do we often overlook their importance to all life on Earth and limit our interest in plant conservation? 

Researchers have noted a growing indifference to plants. There are many reasons for plant unawareness. In urban areas, many people lack equitable access to plants, parks, and natural spaces. Plants are underrepresented in education. From kindergarten to college, plant science is fading from curriculum and school programs. It also has to do with what’s inside our heads: since most plant life is similar in color, mostly stationary, and densely packed, our brains can be hardwired to lump them together instead of noting their differences. In other words, many of us tend to see the forest and not the trees. Importantly, awareness for plants differs across cultures. Most research on the topic has been done in Western societies, whereas Indigenous communities often have a deep and fundamental awareness of plants.

We must increase our awareness and empathy for the plant life surrounding and supporting us. In his 1968 speech to the International Union for Conservation of Nature, Senegalese conservationist Baba Dioum said, “In the end, we will conserve only what we love; we will love only what we understand and we will understand only what we are taught.” The more we engage with plants and experience their positive effects on our health and wellbeing, the more likely we are to protect them. It’s time to become plant passionate.

Modern Medicine and the Power of Plants

Plants have always healed us and today are found in a quarter of our medicines. Yet, most drug researchers focus on synthetically-derived medicines. Despite technological progress, the number of new drugs brought to the market is in decline. However, drug discovery from plants and other natural products continues to be highly productive and effective. 

“Today, we are still challenged by a long list of unmet medical needs for safe and effective medicines,” said Nina Ronsted, NTBG’s Director of Science and Conservation. “One of the grand challenges for humankind remains the identification of new leads for pharmaceutical research,” she continued. The need for new leads is just one reason plant science and conservation are essential not only to the health of our planet but also to our people. “It is not easy to guess which plants might cure which diseases,” said Nina. “As extinction accelerates, we risk losing potential medicines even before they are discovered,” she concluded. 

In recent history, compounds from the Madagascar periwinkle have increased the survival rate of childhood leukemia from 10% to 90%. In addition, a compound initially found in Pacific Yew trees (Taxus brevifolia), is the cancer-fighting component of Taxol. This drug inhibits the rapid multiplication of  cancer cells. Today, Taxol is on the World Health Organization’s list of Essential Medicines and is one of the most effective drugs for treating multiple forms of cancer. 

“The potentially useful compounds that plants have developed over time in response to herbivores overcoming their effects are increasingly complex and specialized,” noted Nina. “Many of these compounds may affect humans and become cures for diseases,” she finished. 

With time, plant research and conservation will reveal more about the connection between plant compounds and human health. But what can we do today to strengthen our connection and improve our health right now? The answer is a walk in the park (or garden!).

Healthy Plants, Healthy Planet

On any given weekday, you’ll find Noel Dickinson of NTBG’s Breadfruit Institute tending to the trees and edible understory plants in the Regenerative Organic Breadfruit Agroforestry (ROBA) demonstration in NTBG’s McBryde Garden. Breadfruit has long been an important staple crop and a primary component of traditional agroforestry systems in Oceania. In addition to providing food and goods, breadfruit agroforests offer broad ecosystem benefits such as soil and water conservation and biodiversity maintenance essential to long-term island habitation. ROBA is a two-acre display garden and model for implementing breadfruit agroforestry in tropical regions and areas of food scarcity worldwide. 

For Noel, breadfruit agroforestry does more than produce nutritious food and regenerate land degraded by erosion, compaction, and loss of organic matter. It nurtures her, builds relationships, and provides an opportunity to learn and grow. “Plants are a huge part of my life, personally and professionally, and breadfruit has had a big impact on me,” said Noel. “Through my work with the Breadfruit Institute at NTBG, I have been able to learn new things as well as literally share the fruits of my labor with my community,” she effused. “I have also, at times, been given a platform to represent the gardens,” she said. “Being an ambassador for not only breadfruit but also NTBG is a great joy for me.” 

Studies show it’s not just Noel benefitting from time spent with plants. Plants can generate happiness, reduce stress, and increase positive energy in the home. In addition, access to parks and outdoor spaces increases rates of physical activity and overall healthiness. Research also shows that people who spend more time around plants have better relationships with the people around them. 

Healthy Today, Here for the Future

Plants and people are inextricably linked. From everyday wellbeing to the next medical breakthrough, we need plants to maintain our health and the health of our planet today. As we navigate and study the effects of climate change, our future also depends on our ability to recognize the plant life surrounding us, learn from it and investigate solutions for what lies ahead.

NTBG’s latest alula research was recently published by Applications in Plant Sciences

For nearly six decades, the National Tropical Botanical Garden (NTBG) has been saving plants. Among the many rare and endangered plant species NTBG is known for conserving is the genus Brighamia, a member of the bellflower family (Campanulaceae), endemic to (found only in) Hawaii. Called alula in Hawaiian, both species — Brighamia insignis and Brighamia rockii — grow on Hawaii’s steep slopes and high sea cliffs. In the 1990s, National Geographic famously photographed two NTBG botanists rappelling over Kauai’s Na Pali coast, collecting plant material to propagate in the nursery.

In the decades since, Brighamia rockii has dwindled to just eleven known plants that cling to the cliffs of Molokai. Its close relative, Brighamia insignis, last seen on Kauai, is now believed to be extinct in the wild. However, thanks to the efforts of NTBG and others, the alula has been successfully cultivated and is even commercially available as a houseplant in Europe and elsewhere. NTBG staff and scientists continue to conserve and study the alula with ongoing research featured in the most recent issue of Applications in Plant Sciences, a publication of the Botanical Society of America.

In an article co-lead authored by NTBG conservation biologist Seana Walsh, scientists show how the adaptation of pedigrees used by the zoo community can be used to manage botanical garden collections and reduce inbreeding, resulting in healthier plants. Researchers selected Brighamia insignis as their case study. Their findings illustrate the importance of maintaining diversity through strategic cross pollinations. 

In the same issue, seedbank and laboratory manager Dustin Wolkis lead authored an article about seed dormancy and germination of Brighamia rockii. The authors found that a high percentage of the seeds germinate over a range of temperatures and are suitable for propagating from seed for conservation. Research suggests these seeds are unlikely to form a long-live soil seed bank and will need human intervention to be reintroduced into the wild.

By continuing to study and conserve this charismatic native Hawaiian plant genus, collaborating with likeminded organizations and institutions, NTBG is playing a leading role in advancing the understanding of rare and endangered plants and ensuring the preservation of irreplaceable biodiversity.

Advancements in drone technology aid in rescuing rare cliff-dwelling plants

The summer of 2022 started off with hopeful celebration at our Conservation Nursery on Kauai as three different critically endangered plant taxa collected by the Mamba drone arm set roots from cuttings – laukahi (Plantago princeps var. anomala), akoko (Euphorbia eleanoriae), and Lysimachia iniki. 

The Mamba, developed by Outreach Robotics with the help of NTBG scientists, is able to collect rare plants from otherwise inaccessible places. Mamba also allows for a much faster retrieval time. What used to take hours of hiking and rappelling to collect plant material, now takes minutes with the Mamba. This result is fresher plant material arriving at our Conservation Nursery and an increase in the likelihood of successful propagation. 

Think of it like rescuing an imperiled person from a remote spot. If you hike to reach the person and carry them to safety on a stretcher, the chance that they are under additional stress is much higher than quickly airlifting them. The sooner we can get the patient (plant) back to the emergency room (our Conservation Nursery), the greater chance of survival.

While attempting to set roots from cuttings in both Lysimachia iniki and akoko has occurred before, it was the first known attempt to do so with laukahi due to its rarity. That all three sprouted roots is an inspiring accomplishment for the Mamba field collection and nursery teams, providing further proof of how new technology can advance rare plant conservation. 

Laukahi (Plantago princeps var. anomala)

Laukahi (Plantago princeps var. anomala) is a small erect or ascending woody shrub that grows on steep slopes and cliffs in wet forests in the Upper Hanapepe and Kalalau valleys on the Hawaiian island of Kauai. Curiously, laukahi is one of more than 250 species in the genus Plantago, largely temperate in distribution, but also occurring at high altitudes in tropical areas and on oceanic islands like Hawaii. While some consider Plantago species like Plantago major to be invasive or ‘weedy,’ Kauai’s Plantago princeps is Critically Endangered with less than 50 individuals known to occur in the wild. 

Further field collection trips with Mamba could have a big impact on the future of critically endangered plants like laukahi. The original cutting is doing well at the nursery and even recently developed a flower stem. A flower means seeds, and seeds mean increased hope for future restoration in the plant’s natural habitat.  

Lysimachia iniki

Past samples of Lysimachia iniki brought to the Conservation Nursery were fragments of plants that had fallen from the sheer cliffs below Kauai’s summit after storms. Incidentally, this is how the species got its name. Lysimachia iniki‘s discovery occurred after Hurricane Iniki’s devastating winds dislodged the native plant from its steep habitat. No past plant fragments brought back to our nursery had ever survived. That is until now. 

Two Lysimachia iniki propagules are thriving under the care of our staff in the Conservation Nursery. There is only one known population of Lysimachia iniki, underlining the importance of this major breakthrough in the conservation of this Critically Endangered Kauai endemic plant. 

Additional Success for Rare Plants

The Mamba has brought additional success beyond laukahi and Lysimachia iniki. A rare Rubiaceae, Kadua st-johnii, grew from a seed collected off of a cutting and a less rare Lysimachia hillebrandii also took root. Lysimachia, a member of the Primrose family, is often difficult to grow from cuttings. The successful rooting of Lysimachia hillebrandii in our Conservation Nursery reinforces that the speed with which Mamba retrieves plant material directly affects survivorship in the nursery.

There have been some setbacks. Akoko (Euphorbia eleanoriae) survived for four months after setting roots. While this specimen did not make it to maturity, it is the first time the species set roots in cultivation. The team at the Conservation Nursery plans to build on the knowledge gained from the first attempt to try again with future field collections. 

Ultimately, the Mamba allows us to reach rare plants that are otherwise unreachable. For some of these cliff-dwelling species or any plants that grow in hard to reach areas, these developments in drone technology may be the best hope for their continued survival. “The use of drones also allows a fast turnaround for processing cuttings and placing them in our mist-house or in a temperature controlled location for protection,” says NTBG Nursery Manager, Rhian Campbell. “As we continue to develop protocols for the handling of these cuttings and learn everything we can about propagating these extremely rare species, we are also likely to become more successful with them over time.”

Cutting edge drone technology leaves nothing beyond reach.

By Ben Nyberg, GIS and Drone Program Coordinator

NTBG members who have been supporting our work for years know that the discovery, collection, and conservation of rare plants is central to our mission. Roughly 90 percent of the Hawaiian flora is found nowhere else on Earth, and so saving these plants is a great responsibility. But on an island like Kauai, where many rare plants grow in steep terrain and sheer cliffs, they can be impossible to access on foot.

For decades, NTBG has used traditional rappelling techniques to reach endangered cliff-dwelling plants like alula (Brighamia rockii) but in some cases, the plants are inaccessible to even the most experienced rappellers. In 2016, NTBG began experimenting with drone technology to discover plants that were otherwise beyond our reach.

Soon after our drone program began, we were encouraged by a number of rare plant discoveries in remote, previously unexplored cliff habitat. Drone technology was an exciting new tool that revealed rare plant populations we never imagined we could explore, but even as we made progress, we asked, “what’s next?”

The answer came when we were approached by a group of Canadian researchers from the University of Sherbrooke in Quebec who were grappling with similar challenges. The researchers had started a company, Outreach Robotics, and developed a drone mechanism they called DeLeaves that could collect plant material from treetops.

Their drone carried a tool suspended below it that can grasp and cut plants mid-air. DeLeaves proved highly effective for collecting plants directly below a drone, but could it be used on Hawaii’s sheer cliffs?

Excited by the chance to collaborate with the robotics team, we applied for a grant from the National Geographic Society with the hope of funding the development of a horizontal collecting arm. Our goal was to design a robotic arm that would enable us to collect seeds and cuttings from small, often fragile cliff dwelling species in Hawaii. When our application was approved, we quickly started the design process.

In our attempt to overcome the challenges of Hawaii’s extreme cliffs, we explored everything from long, extendable poles to semi-rigid vacuum hoses, and even one design that snapped like a clam shell. We were planning for our initial field trials when the COVID pandemic brought our work to a halt.

What at first appeared to be a major setback, later proved to be to our advantage. Travel restrictions delayed field trials for almost two years, but that allowed the team at the robotics lab in Quebec to build, test, and redesign the collecting arm without disruption. In the fall of 2021, as international travel was reopening, the team unveiled the MAMBA (Multi-Use Aerial Manipulator Bidirectionally Actuated). The draft design featured two independently functioning components — a lifting drone and the MAMBA mechanism.

MAMBA is suspended below the lifting drone but, unlike the earlier DeLeaves design, it has propellers that move the collecting arm forward and back like a pendulum. The device has a separate controller and remote video feed, allowing the MAMBA pilot to clearly see minute details within inches of the plant and cutting piece. The sampling head rotates in multiple directions, enabling the pilot the ability to align with and collect their branch of choice.

In October 2021, we initiated the first set of field trials on Kauai. Within a few hours of test flights in McBryde Garden, we felt comfortable deploying MAMBA into the wild. We were thrilled to find the device was stable, precise, and easy to operate. Focusing on target species such as akoko (Euphorbia eleanoriae), dwarf iliau (Wilkesia hobdyi), and hau kuahiwi (Hibiscadelphus distans), the MAMBA performed well, allowing us to secure collections from each species, in some cases from more than half a mile away.

Following our initial trial flights, the robotics team returned to Quebec where they continued to refine MAMBA. In March 2022 the team returned to Kauai ready to help us attempt to collect from target species which were particularly difficult subjects due to the plant’s growth habit or location.

These Kauai endemic species, all Critically Endangered, include Lysimachia inki, Kadua st-johnii, Lysimachia scopulensis, and laukahi (Plantago princeps var. anomala).

To better appreciate the challenges of collecting these extremely rare plants with this new technology, consider the case of Lysimachia iniki which grows on 3,000-foot high cliffs below Kauai’s summit, one of the wettest places on Earth. The extreme terrain and rainfall make this a particularly difficult area to operate drones.

After lugging the cumbersome equipment along muddy slopes and across a rushing stream, we were able to use a spotting scope to find plants with flowers and seeds. Climbing into the mist, the drone carried MAMBA to our target plants where we successfully collected a cutting from the sheer green wall and delivered it to us far below.

To our knowledge, the MAMBA collection of L. iniki was a first. The plant had been collected opportunistically after storms for the last 30 years, but our intentional collection yielded a large number of seeds from a healthy specimen, allowing us to deposit this invaluable collection to our seed bank and cuttings to our nursery where they rooted in captivity for the first time.

“Understanding the distribution and abundance of rare and endangered plants is a critical first step in their conservation.“

Ben Nyberg, GIS and Drone Program Coordinator

Another example of how drone technology is advancing rare plant conservation is our use of MAMBA to collect a sample from the extremely rare wahine noho kula (Isodendrion pyrifolium), a plant we were unable to identify by drone survey alone. After watching the MAMBA remotely cut and collect the plant, our excitement swelled as the drone returned. There is an undeniable thrill in extending one’s human hand to receive a botanical treasure from a robotic hand.

Previously documented on Niihau, Maui, Lanai and Hawaii Island in the mid 19th century, Isodendrion pyrifolium was thought to be extinct for more than a century until it was rediscovered on Hawaii in 1993. Another population was found on Oahu in 2015, but it was the MAMBA that allowed us to actually collect the species for the first time on Kauai.

Understanding the distribution and abundance of rare and endangered plants is a critical first step in their conservation. Drone technology makes this possible. Collecting seeds and cuttings from remote plant populations is the next step. Now drones can do that too. A third critical step in the conservation of plants is returning species to their natural habitat.

New projects now underway will eventually allow us to sow seeds onto inaccessible steep slopes. What we thought was impossible just five years ago is now reality. Armed with these new tools, a commitment to cooperation, and the determination to succeed, we are hopeful that these new discoveries will continue to positively impact plant conservation in Hawaii and far beyond.

Kauai, Hawaii

Researchers in Hawaii and Canada have developed a robotic arm that remotely collects endangered plants from high cliffs

Scientists at the National Tropical Botanical Garden (NTBG) in Hawaii, along with engineers at Outreach Robotics and researchers from the University of Sherbrooke in Quebec, Canada have designed a remotely controlled arm that can collect rare and endangered plants while suspended by a drone.

Their progress has been published in the journal Nature – Scientific Reports, documenting how the new technology is redefining rare plant conservation on high cliffs and other extreme habitat.

The partnership centers around an aerial robotic sampler roughly the length of a fishing rod equipped with eight propellers and a cutting mechanism which is suspended by a drone. The arm, called Mamba, can be operated remotely up to one mile (1.6 km) away. In flight trials, NTBG scientists and their partners have successfully collected seeds and cuttings from remote plant populations of extremely rare native species such as Lysimachia iniki and Isodendrion pyrifolium which grow on sheer cliff faces that are otherwise inaccessible.

NTBG drone specialist Ben Nyberg calls the technology “ground-breaking” and said, “this combination of robotics and botany is exciting, and is already having an amazing impact both in species conservation and the knowledge we’re gaining about cliff environments.”

Once retrieved by Mamba, the plants are recorded and brought to NTBG facilities where seeds are stored in a seed bank for conservation and research. Other seeds and cuttings are propagated in the nursery where they are grown and later used for restoration projects and returned to the wild.

NTBG nursery manager Rhian Campbell said the new technology can potentially increase success rates in growing rare plants because wild cuttings reach the conservation nursery much faster and in better condition than if they had been retrieved by hand. “The amount of time fragile cuttings spend under stress is minimized. Mamba allows us to collect multiple species very efficiently in a fraction of the time it used to take,” said Campbell.

NTBG is based on Kauai which is recognized as a biodiversity hotspot and is the oldest of Hawaii’s inhabited islands. Kauai is home to 255 plant species found nowhere else on Earth, nearly 90 percent of which are classified as Endangered or Critically Endangered based on IUCN Red List criteria. The remaining ten percent are extinct or nearly extinct in the wild.

For decades, NTBG botanists have used helicopters, rappelling, and rough terrain roping techniques to discover and collect plant material from some of the world’s rarest and most difficult to reach plant species. 

Since 2016, NTBG has been using drones to discover rare plant populations previously thought to have gone extinct or otherwise unknown. NTBG’s collaboration with Outreach Robotics and the University of Sherbrooke in Quebec began in 2020.  

Trial flights using Mamba include partnering with the State of Hawaii’s Department of Land and Natural Resources Division of Forestry and Wildlife (DOFAW) and the Plant Extinction Prevention Program. Adam Williams, a DOFAW botanist said, “Mamba has exceeded our wildest expectations, turning science fiction into reality. Surveying and collecting from a thousand-foot-high cliff from a mile away is just mind-blowing.”

Calling Mamba a “game changer,” NTBG’s Nyberg added, “it allows us to reach critically endangered species that are down to just a few individuals. It can be the difference between extinction and survival.”

The mission of the National Tropical Botanical Garden is to enrich life through discovery, scientific research, conservation, and education by perpetuating the survival of plants, ecosystems, and cultural knowledge of tropical regions.

Press kit with content and guidelines available here.

Learn more about the work of the National Tropical Botanical Garden at www.ntbg.org.

Learn more about NTBG’s drone program at www.ntbg.org/science/conservation/drones/.

Learn more about the work of Outreach Robotics at www.outreachrobotics.com.

For media inquiries, contact: media@ntbg.org