Category: Native Plants

Great Blue Lobelia (Lobelia siphilitica) is a quirky plant.

It is undeniably beautiful, with spikes of blue-violet flowers, 2 to 3 feet tall, blooming at summer’s end. It is adored by bumblebees, host to several species of butterflies and moths, and frequently visited by hummingbirds. 

But you never know where it’s going to pop up! 

Great Blue Lobelia is native to wet meadows in the Eastern half of the US from Maine to Georgia and west to Colorado and Texas. It is not truly perennial since the flowering stem and its roots die off after forming seeds. But in a favorable location, Lobelia seeds itself around — enthusiastically! — to maintain a perennial-like presence. 

Lobelia seeds are tiny, like brown dust, which accounts for their easy dispersal. Whether they are carried by wind, water, animals, or even human footsteps is not entirely certain, but they seem to need open soil, moisture, and sunlight to develop into flowering plants.

Each plant begins as a semi-evergreen rosette, a circular cluster of leaves close to the ground. You may not even notice it until it begins to send up stalks in mid-summer with 2 to 3-inch-long pointed leaves. Then, in late August, the flowers begin to open sequentially from bottom to top. In a wooded area, the effect of the blue flowers is cool and soothing. In full sun, the display is a show-stopper!

Like its sister plant Lobelia cardinalis, Great Blue Lobelia needs moisture. In a wet summer, Lobelias can surprise gardeners by appearing in large numbers where they were not intentionally planted and never appeared before! (See “How Did That Get Here?” about the red Lobelia, Cardinal Flower). The plants do well in sun or part shade in Zones 3 to 9 in average soil. They are perfect along streams and ponds, and can even survive occasional standing water, but not drought.

But most of us are happy to see Lobelia pop up wherever it chooses. As summer fades to fall, the flowers are more than welcome and pollinators are happy to have nourishment before the weather turns.

The odd history of Great Blue Lobelia adds to its eccentricity. As the scientific name Lobelia siphilitica suggests, the plant was once thought to be a cure for syphilis. Native Americans used the plant’s roots and leaves to treat coughs, nosebleeds, headaches, and colds. If they used it at all to treat syphilis, it was mixed with a complex concoction of multiple herbs. Nevertheless, Europeans began using it as a syphilis remedy in the mid-1700’s when Sir William Johnson, Britain’s appointed Indian agent, bought it from enterprising local herbalists and sent it back to England as the natives’ “secret” cure. Sadly, in 1818, William Barton’ s book, Vegetable Materia Medica of the United States, concluded that despite trying the treatment in every favorable circumstance, “physicians of eminence” had found it to be ineffective against syphilis. Today, we know that Lobelia siphilitica contains a variety of toxic alkaloids similar to nicotine that can cause vomiting and other adverse reactions. 

While Great Blue Lobelia may not be a cure for its Latin namesake disease, it is very effective for brightening our late summer landscapes and supporting native wildlife. 

So, we still prescribe it!

THIS BLOG IS AUTHORED WEEKLY BY CATHY LUDDEN, CONSERVATIONIST AND NATIVE PLANT EDUCATOR; AND BOARD MEMBER, GREENBURGH NATURE CENTER. FOLLOW CATHY ON INSTAGRAM FOR MORE PHOTOS AND GARDENING TIPS @CATHYLUDDEN.

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Have you ever seen an azalea blooming in August? It is a rare sight, indeed!

Plumleaf Azalea (Rhododendron prunifolium) is the latest-blooming of all North American azaleas. It starts blooming in late July or August, months after other azaleas have finished, and it has been reported still blooming in October!

It is also the rarest of North American azaleas, native to only two states in the US. In the wild, a few small populations grow in forested sandy ravines along streams that drain into the Chattahoochee River, on the border between Georgia and Alabama. Sadly, even those few existing wild populations are threatened by development and careless logging practices, so the only native habitat of this amazing shrub is rapidly disappearing. Rhododendron prunifolium is under consideration for Endangered Species classification, but is not yet on the official list.

Plumleaf Azalea is strikingly beautiful. Its flowers are a deep red-orange with extra-long stamens that curl outward like exaggerated false eyelashes. The flowers are not particularly fragrant, but bees do visit them.

Despite its very limited native range, the shrub does very well in gardens throughout the Eastern US in Zones 5 to 7. It prefers rich, acidic soil, even moisture, and dappled sun. It has a rounded, fairly compact shape, and will reach 5 to 8 feet tall and 3 to 4 feet wide. It is an absolute show-stopper in a shady garden when nothing else is in flower.

A plant as rare as Plumleaf Azalea poses a challenging question for ecology-minded gardeners. If it is native only to a limited area in Alabama and Georgia, should we be planting it in Northeastern gardens? There are several considerations:

We know that plants introduced into areas where they are not native can become invasive and cause ecological harm. (See our blog posts on very aggressive invasive plants introduced from other continents: Nip ‘Em in the Bud!, Evil Ivy Over Everything, and Boo!) While there are some native US plants that have become a nuisance when introduced outside their native range to other parts of the US, the danger is far less than with plants introduced from other continents. Plumleaf Azalea does not spread itself by the roots, and is not easily spread by seed, so it is not likely to move into areas where it is not intentionally planted.

But we also know that the value of any given plant to an ecosystem is greatest within its native range because it will have co-evolved with the other plants and animals in that ecosystem. A Colorado Blue Spruce, for example, supports insects native to the Rocky Mountains, but is of little use to most insects in the Mid-Atlantic region. Similarly, we can imagine that insects native to the Northeast may have no use for a plant from Alabama, though insects that evolved along the Chattahoochee River may depend upon that plant for survival. It is not known whether Plumleaf Azalea is a host plant for insects outside its native range, or whether it is useful to pollinators in the Northeast, but we do know that plants native to the Northeast are more valuable to local insects.

For these reasons, the best ecological choice is to plant species native to your specific region. But what if a plant is endangered in its own native region?

Michael S. Dosmann, writing for the Arnold Arboretum at Harvard University in 2022, noted that shortly after the founding of the Center for Plant Conservation in 1984, the Arnold Arboretum began collecting seed from disappearing populations of Plumleaf Azalea in three counties in Georgia. The goal was to prevent the extinction of the species. As of last year, the Arboretum was growing 34 Plumleaf Azalea shrubs – in Massachusetts. He said “preserving wild populations remains the highest priority, but it is important to have a back-up…”.  He also observed that Plumleaf Azalea looks great in the garden, and for endangered species, “being charismatic and attracting attention is a gateway to its security (just look at the giant panda)!” Does planting Plumleaf Azalea in our gardens provide additional “back-up” for conservation of an endangered species? Maybe…

With that justification, anyway, growing a beautiful rare azalea that flowers in August (!) is practically a public service!!

THIS BLOG IS AUTHORED WEEKLY BY CATHY LUDDEN, CONSERVATIONIST AND NATIVE PLANT EDUCATOR; AND BOARD MEMBER, GREENBURGH NATURE CENTER. FOLLOW CATHY ON INSTAGRAM FOR MORE PHOTOS AND GARDENING TIPS @CATHYLUDDEN.

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In early summer as bees, butterflies, and hummingbirds search for nectar and pollen, they find incredible bounty in Monarda – a group that includes some of our most beautiful and valuable native perennials. Watching wildlife enjoy Monarda on a summer day is only part of the pleasure – Monarda has other gifts for humans as well.

The Monarda genus is “endemic” to North America, meaning it is native only to this continent. There are over 20 species of Monarda, and 3 of them, all known variously as “Bee Balm,” “Wild Bergamot,” and “Oswego Tea,” make great garden plants in the Eastern US. All three are colorful, sun-loving, easy to grow, and deer resistant. The pom-pom flower heads are actually clusters of individual tubular flowers loaded with sweet nectar that attracts hummingbirds and a huge variety of pollinators. Flower colors range from pale lavender to pink to flame red.

Monarda fistulosa (most frequently called “Wild Bergamot”) stands 4 to 5 feet tall and blooms with showy lavender flowers from July through September. It is tolerant of poor soil and can handle periods of drought. A true meadow plant, this Monarda is native to most of Southern Canada and almost all of the US east of the Rocky Mountains.

Monarda didyma (most often called “Bee Balm”) is typically bright red, though there are natural variations and cultivars in different shades of rose and pink. It is shorter than Monarda fistulosa, usually topping out at 3 to 4 feet. It prefers more moisture and is a more aggressive spreader. Monardas are in the mint family and spread by rhizomes as well as seed. While M. fistulosa is less aggressive, Monarda didyma can take over a small flower bed sending runners in every direction, so plant it where it has room to roam. It will form a stunning colony in the right place, with full sun and fairly rich soil. Hummingbirds find it irresistible.

Monarda bradburiana is native to the warmer climates of Southeastern and Southcentral US, but is hardy in Zones 5 to 8, so it does very well as far north as Connecticut, New Jersey, and parts of New York. It is a great garden plant because it is a clump-former, not spreading aggressively by rhizomes, and grows only 1 to 2 feet tall. It blooms in June, earlier than other Monardas, and has interesting shaggy flowers in pale pink.

The common names for these Monarda species seem to overlap. All of them are called “Bee Balm” by many gardeners. And while the name “Wild Bergamot” most often refers to M. fistulosa, it is frequently applied to M. didyma as well. And both M. fistulosa and M. didyma are commonly called “Oswego Tea.” Though botanists would wag a finger and say this is exactly why common names are confusing, all three of these names actually are appropriate for all three plants. 

“Bee Balm” refers to an ancient medicinal use of Monarda. Indigenous Americans taught European settlers that applying shredded (or chewed!) Monarda leaves to insect bites or stings neutralizes the pain and speeds healing.

“Wild Bergamot” refers to the flavor of “Oswego Tea.” Indigenous people of the Oswego River area in upstate New York introduced settlers to a delicious tea made from Monarda leaves and flowers. The flavor reminded Europeans of the taste of Bergamot orange, the flavoring in Earl Grey tea. It is often said that after the Boston Tea Party, colonists turned to Oswego Tea and boycotted the English product. That isn’t really a sacrifice: try adding steaming water to a handful of torn Monarda leaves and let it steep for 10 minutes. It’s delicious! Add a little honey and it’s even better.

As an herbal seasoning, both the leaves and flowers of Monarda are very good. Dried leaves of M. fistulosa, which are spicy as well as minty, can be used to season roasted meats. The fresh flowers of M. didyma (pulled individually out of the cluster), have a sweet and citrusy flavor that goes well with fruit, and in salads. Though Monarda plants are vulnerable to powdery mildew if conditions are too damp, it is easy to avoid the affected leaves and select newer growth along the stem and near the flowers.

Monarda is known to have anti-microbial and antiseptic qualities. The tea helps with sore throats, mouth sores, and gastric symptoms. Poultices and salves made with Monarda are said to prevent infection and aid in healing skin wounds. Early American colonists also learned to plant Monarda around their beehives. Not only does the honey pick up flavor from the flowers, the anti-microbial effect of Monarda helps prevent diseases in the bee colony.

So, try a cup of Oswego Tea, hot or iced, and watch the hummingbirds, butterflies, and bumblebees share the gifts of Monarda. It is a balm for all of us.

THIS BLOG IS AUTHORED WEEKLY BY CATHY LUDDEN, CONSERVATIONIST AND NATIVE PLANT EDUCATOR; AND BOARD MEMBER, GREENBURGH NATURE CENTER. FOLLOW CATHY ON INSTAGRAM FOR MORE PHOTOS AND GARDENING TIPS @CATHYLUDDEN.

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Red Buckeye (Aesculus pavia) and Bottlebrush Buckeye (Aesculus parviflora) are two excellent flowering shrubs for home landscapes. If you’re ready to move beyond the ordinary, take a look at these beautiful buckeyes.

You’ve probably heard of Ohio Buckeye, a large Midwestern shade tree (Aesculus glabra) that has given its nickname to the state of Ohio, as well as its citizens, sports teams, and even a popular candy. The name comes from the large hard-shelled nut produced by the tree and said to resemble the eye of a deer. Of much greater interest for landscapes in the Eastern US, however, are two native shrubs that go by the same name and are in the same genus.

Both shrubs evolved in rich, shaded woodlands in the Southeastern US. Now successful well beyond their native range, they are grown in Zones 4 through 9 from New England to Florida. Stretching the definition of “native” a bit seems justified for these beautiful shrubs because of their value to hummingbirds and bees, as well as their superior garden merits.

Red Buckeye (Aesculus pavia) blooms first, in mid-May. One of its common names, “firecracker plant,” is not an exaggeration! The scarlet flowers blaze out of the shade in wooded areas, competing for attention with rhododendrons and azaleas. The tubular flowers seem custom-made for hummingbirds, blooming just as hummingbirds arrive for the season.

Bottlebrush Buckeye (Aesculus parviflora) blooms much later. The flower buds stand vertically above the leaves in June, like candles on a birthday cake, but they don’t open until July, when few other shrubs are in flower. The “bottlebrush” flowers are large, white, fluffy, and very attractive to pollinators. They are eye-catching in shade, and last for many weeks.

Like other plants in the buckeye family, both shrubs have large, dark green leaves that are “palmate,” meaning shaped like a hand, with five long narrow leaves on each stem. The leaves have a relaxed, slightly drooping habit, and gradually turn a soft yellow in the fall. Red Buckeye drops its leaves early, and for that reason, may look best with shorter shrubs planted in front of it.

All parts of buckeyes are moderately toxic to humans and most animals. Deer may sample the shrub, but will learn to leave it alone. After flowering, the shrubs produce a globular pod containing large seeds. Squirrels seem to be the only animals interested in them. Indigenous people used the ground seeds of Red Buckeye to poison fish, making them easier to catch. But when prepared properly to remove toxic saponin compounds, buckeye nuts can be ground into a nutritious flour.

Both buckeye shrubs are slow-growing, but they are large and need room to spread their branches in the landscape. Red Buckeye grows taller, 10 to 20 feet, and up to 15 feet wide. It is a clump forming plant and will stay where you put it. Bottlebrush Buckeye stays shorter, 6 to 8 feet tall, but grows up to 20 feet wide. It is a “suckering” shrub that sends out runners tending to form colonies over a number of years. In the right spot, both are low maintenance shrubs.

Buckeyes are understory plants and live happily in moist, organically rich soil. They can take full sun if they have enough moisture, but do better with afternoon shade in hot summers. Planted at the edge of a lawn (or meadow!) with tree cover above, buckeyes will do well, but the ideal spot is in a wooded area where autumn leaves are allowed to remain to enrich the soil. Buckeyes have a loose, open branching habit, so it is easy to underplant them with native ground covers.

If you want to create a diverse native woodland for birds, bees, and butterflies, create some habitat by adding these buckeyes under a tree or two — and enjoy the view! 

THIS BLOG IS AUTHORED WEEKLY BY CATHY LUDDEN, CONSERVATIONIST AND NATIVE PLANT EDUCATOR; AND BOARD MEMBER, GREENBURGH NATURE CENTER. FOLLOW CATHY ON INSTAGRAM FOR MORE PHOTOS AND GARDENING TIPS @CATHYLUDDEN.

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