Meet Stevia Rebaudiana: The Plant Behind the Hype

stevia rebaudiana

Stevia rebaudiana, the plant behind the popular sweetener

Last week, I was vacationing in Canada when an interesting commercial popped up on the television. It was an ad for the sweetener, stevia, and it featured enthusiastic users growing plants at home. Needless to say, it caught my attention. I had heard that stevia was derived from a ‘natural’ source. But I’d never stopped to consider what that meant from a gardening perspective.

I decided to dig deeper.


These days, stevia is perhaps best known as an alternative to sugar. But in the botanical world, it is a genus of about 240 species of herbs and shrubs from the sunflower family,  Asteraceae. Among the species, only one exhibits the highest level of sweetness; Stevia rebaudiana. Native to Paraguay and Brazil, the herb has been used for centuries to sweeten tea and food as well as to treat various ailments and diseases.

plantation in Indonesia

A stevia plantation in Indonesia/Photo:

We have the Paraguayan chemist Ovidio Rebaudi to thank for identifying what makes Stevia rebaudiana so sweet. In 1900, he began studying the plant to determine its constituents. He discovered that stevia rebaudiana’s leaves were packed with compounds called steviol glycosides. And, when extracted and refined, these compounds were 200 times sweeter than processed sugar.

In fact, it took only a small amount of stevia to produce the same level of sweetness as sucrose. And since humans were unable to metabolize steviol glycosides, the extract was not only calorie-free, but also didn’t raise blood sugar levels when digested. 

It’s no wonder the world was jumping on the bandwagon.


Powder and dried leaves of fresh stevia

According to the latest report by IMARC Group, the global stevia market reached a value of more than USD 490 million in 2018 and is projected to reach nearly USD 818 million by 2024. Stevia currently represents an almost 40% share of the total global sugar substitutes market. However, it also has its share of detractors.

Take, for instance, the way in which it’s processed. This is what the website says about its processing:

To extract the plant’s sweetness, stevia leaves are harvested, dried and steeped in hot water. They then undergo multiple stages of filtering and centrifuging to concentrate the sweetest components of the leaf. The result is purified stevia leaf extract, ready to be sold commercially.

IMARC global stevia market report

IMARC Global Stevia Market Report

Online, however, there is much disagreement about stevia’s suitability for food. A deeper dive reveals that although stevia leaf extract comes from a natural source (the plant), its leaves are generally processed in a lab with hot water as well as with the chemical compound, ethanol.

Adding to the confusion is that the FDA considers the highly purified form of the plant’s leaves to be Generally Recognized As Safe (GRAS) – (that is, the steviol glycsoides found in the leaves). But to date, it has not approved whole stevia leaves and crude (non-purified) stevia extracts for use in food due to the lack of generally accepted specifications.

Maybe the herb is best grown and processed at home.


Ready to follow the people in the ad and grow your own stevia? The sun-loving perennial is listed as hardy to USDA Plant Hardiness Zones 11 and up. Like most tropical species, it thrives in hot climates and will die back in a freeze. However, in most areas of the country it can be grown successfully as an annual. 

stevia rebaudiana leaves

Leaves of stevia rebaudiana

In fact, according to Park Seed (one of the oldest seed companies on line), stevia rebaudiana takes well to containers. They recommend planting 3 to 5 plants per pot. Like other herbs, stevia rebaudiana benefits from frequent pruning to prevent lankiness and to encourage branching. Expect it to grow to around 24″ tall.

In early to mid autumn, the herb will produce bunches of tiny, tubular white flowers. But if you’re planning on harvesting fresh leaves, make sure to do so before they’ve opened. Once the flowers blossom, the leaves often adopt a bitter aftertaste.

white flowers of stevia rebaudiana

White flowers of stevia rebaudiana

Stevia growers recommend harvesting fresh leaves in the morning when the plant’s sugar content is highest. You can eat the leaves directly off the plant or dry them and save them in airtight containers. Dried leaves are generally sweeter than fresh ones. And they can be ground in a blender into a granulated powder.

dried stevia leaves

Dried stevia leaves

A note on cold drinks- the leaves must be steeped in hot water to release their sweetness. So use fresh leaves as a sweet, edible garnish instead. 



10 New Year’s Resolutions For The 2020 Garden

Given my preference for long days spent in the garden, December 21 is always cause for celebration. That’s because from that point forward every day will get just a little longer. And with the return of the light, my mind is filled with thoughts of the garden and plans for what the New Year will bring.

If you’ve been following this blog, you know that every year I post my New Year’s resolutions for both my individual and clients’ gardens. So without further ado, here they are below.


Given our changing climate, environmentally-responsible, sustainable landscapes are becoming more and more in vogue. As a result, you can now find more native species for sale at the nursery. These plants tend to look a little less ‘finished’ than what we are used to, but the flip side is that they come with many benefits.

Not only are native plants more hardy (since they are evolved to local conditions), but they also require less watering and fewer pesticides and fertilizers. Moreover, they provide food and habitat to birds and other local wildlife.

blue cardinal flower

Blue cardinal flower, Lobelia siphilitica, is a native plant of Maryland

This year, I resolve to learn more about my area’s native plants and add a few new species to my gardens. 


Most of us love birds, but can we name the ones visiting our garden? The legendary Ted Parker, who was known for his ability to identify thousands of birds by their songs alone, said

“Birding in tropical forests by sight alone is like watching the news on television with the sound turned off – you’ll miss most of what’s going on.”


The vireo is a small songbird native to Virginia

This year, I resolve to learn a handful of songs and begin building my birdcall repertoire. If this sounds like a good idea to you, too, writer Kenn Kaufman of Audubon News has some great suggestions for how to do so, including online bird guides, free ID apps and some good old-fashioned books.


Until last year, (when I and my team were growing massive amounts of zinnias for a wedding), I had had little experience with growing plants from seed. Truth by told, I was afraid of the whole project. Something about laying those tiny kernels in the potting mix shook my confidence in my own planting abilities.

But thanks to our efforts, I and the rest of my team (who were not afraid), were rewarded with hundreds of beautiful plants by mid-summer. Moreover, they were varieties that weren’t available at local nurseries. This helped me realize that growing plants from seed is not only economical, it opens up a whole new world of planting possibilities.

growing seeds

This year, I resolve to grow more annuals from seed to supplement the other plants in my gardens. 


While the huge purple globes of Allium ‘Globemaster’ get all the glory, there are many other spectacular allium species that bloom all through summer right up to the first frost. These include the mid-summer flowering Blue Globe Onion (Allium caeruleum) Stars of Persia (Allium cristophii) and adorable Drumstick (Allium sphaerocephalon), to name just a few.

Allium 'Drumstick'

Adorable, summer-blooming Allium ‘Drumstick’

In the fall, I resolve to plant a bunch of these other, lesser-known species to enhance the show in my 2021 garden.


For some time, I’d been watching moss slowly form a carpet under my flower pots. I knew I needed to add some pot risers, but hadn’t found any that didn’t detract from the look of the container. That is, until Julie Friedman of Exteriors Landscape Design recommended some invisible flower pot risers called LIFT MY POT. Made out of heavy black rubber, the round risers got the job done while completely disappearing from view. 

clay flower pots

I resolve to order more of these risers for the rest of my pots (and my clients’ pots) next season.


It seemed like fall 2019 was a time of garden rehab for my business. In early December, we hand pruned a large number of overgrown shrubs on two separate properties. One of my team members is an accomplished boxwood pruner (having apprenticed at the historic Georgetown estate called Dumbarton Oaks). Watching his technique as well as the tools he employed inspired me to come home and coax all my own boxwood into spheres. For a perfectionist like me, it was a deeply satisfying experience.

pruning shears

However, as we all know, good tools make a job more enjoyable and over the years, my tools have suffered much neglect. This year, I resolve to take better care of my pruning shears (perhaps buy some new ones) and keep them in clean and sharpened condition.


There are raspberries and then there are raspberries. Two years ago, a client of mine introduced me to the golden kind. Milder than their red cousins with a fuller, sweeter taste, they are the perfect summer snack right out of the garden. Golden raspberries come in both summer and fall-bearing varieties. including ‘Honey Queen’, ‘Fall Gold’, Golden Harvest’ and Anne’.

golden raspberries

Golden raspberries

This year, I resolve to add a small hedgerow of golden raspberry plants to my garden.


Almost nothing speaks ‘garden’ more than a long line of hydrangeas, the quintessential summer hedge. Yet many people opt for a single specimen or just a few, missing out on the grand statement these dramatic shrubs can make in a mass.

Although I’m partial to the old-fashioned, part-shade mophead varieties, my favorite easy-care species for full sun is the limelight hydrangea.

hydrangea hedge

Hydrangeas have the biggest impact as a hedge

This year, I resolve to make a grand statement and plant a limelight hydrangea hedge along the brick wall in the back of my garden.


Don’t we all wish for a better hose? I’ve tried them all from the rubber to the cloth. They’re either too heavy, always crimping, or just don’t feel right in my hands (like the accordion models in rubber or cloth). Luckily the wirecutter examined a bunch of them and came up with some recommendations. In 2019, they concluded that the neon green Flexzilla was the most kink-resistant material they tested. It lay flat and twisted and turned more easily than the others.

flexzilla garden hose

The lime green Flexzilla garden hose

I resolve to experience the joys of watering again and buy a Flexzilla garden hose for 2020.


Not everyone is a fan, but the facts are things are getting drier. If you want to save on irrigation and not worry if your plants will die over vacation, grasses are the ticket. That’s because, unlike more shallow-rooted perennials, grasses have long roots that penetrate deep into the soil to capture water other plants can’t reach.

Pampas, maiden and purple fountain grasses are all dependable garden denizens. But nowadays there are so many other exciting options available (including many species that come in more manageable sizes.) These include Little Blue Stem, Purple Moor Grass, Blue Oat Grass and Pink Muhly Grass, to name just a few.

festuca glauca

Blue fescue is a great, small sized grass with silver-blue foliage

This year, I resolve to expand my grass library and add some unusual specimens to my garden. 

Wishing all of my readers a wonderful New Year and successful 2020 season in the garden!


A Beginner’s Guide To The Different Types Of Daffodils

Next week, I’ll be planting my daffodils in what has become for me an annual tradition. Why, you may ask, since they multiply so quickly? Well nowadays, daffodils come in an astonishing array of colors, shapes and sizes. So each year, I add a few more varieties to my garden, while savoring the list of further possibilities. Continue reading

Drink To Your Health With These 10 Best Medicinal Teas

cover 3

Now that temperatures are dropping and we’re spending more time indoors, almost nothing beats a cup of freshly brewed hot tea. And aside from the warm and cozy feeling a steaming mug evokes, tea has never looked better. That’s because many ‘true’ and herbal teas are packed with powerful antioxidants and other substances that are great for human health. So before reaching for a pill, why not explore the benefits of medicinal tea? Continue reading

Lespedeza: The Best Fall-Flowering Shrub You’ve Never Heard Of

lespedeza thunbergii

Lespedeza thunbergii

Lespedeza. Judging by the sound of it, you’d think it was an island off the coast of Italy. And the plant that bears its name certainly looks Mediterranean. Yet, I had never heard of this magnificent, fall-blooming shrub until a client of mine showed me a pair in her garden. Here’s why I’ve been a fan ever since. Continue reading

The Late-Summer Delights Of Sedum ‘Autumn Joy’

sedum autumn joy in the garden

Are you on the hunt for a dependable plant for your late-summer garden? Look no further than sedum ‘Autumn Joy.’ Come August, its lovely clusters of tiny flowers are just starting to adopt a rosy-pink hue. And best of all, the blooms keep going for weeks, gradually turning a dusty red that’s the perfect compliment to fall. Continue reading

Chesapeake Bay Wildflowers: July’s Top 10 Bloomers


‘There are always flowers for those who want to see them’ – Henri Matisse

For most of my life, I’ve been more attracted to ornamentals than to wildflowers. Even though I’ve noticed many beautiful species in the landscape, I’ve never really taken the time to observe them. You might say, I’ve been wildflower blind. Continue reading

How To Cope With Boxwood Blight: An Expert Weighs In

It’s not every day you get to discuss your problems with an international expert. But Lynn Batdorf is the real deal. Batdorf is the world’s top resource on everything boxwood, including all of the diseases and pests that affect this diverse species. Recently he spoke to me about how to deal with the latest threat to our gardens, the dreaded boxwood blight. Continue reading

Why Star Magnolia Deserves A Spot In Your Garden

Magnolia stellata, commonly known as Star Magnolia

First introduced from Japan in the 1860s, star magnolia has long been a resident of the American garden. One of the smallest magnolias, it produces a cloud of showy white or pink flowers in early spring. The blossoms appear before the leaves, dangling like fallen stars on the tree’s smooth, bare branches. It’s enough to leave you speechless. Continue reading

The Best Hellebore Varieties For Your Winter/Spring Garden

February can be a bleak time on the East Coast. Days are short and the sky hangs low on the horizon. But there’s a small-sized perennial whose early, colorful blooms never fail to lift my mood. It’s the lovely, cup-shaped flower called hellebore, commonly known as the Lenten Rose. Continue reading