If a rose by any other name would still smell as sweet, would an ironweed by any other name still be as tough-as-nails, bombproof, or utterly indestructible?
Whatever you do, don't ask Romeo!
It’s so hard being a gardener. We spend so much of our planning time being the impulsive, young Montague. We can’t have what we want, be it Rosaline or that fancy new Himalayan gentian that’s the color of a well-nourished Smurf. We whine. We moan. We drone on to anyone who will listen. And then, pawing through the pages of the newest catalog, there she is ... Juliet (otherwise known as the variegated, purple-leafed, whatchamacallit), and in the blink of an eye, “Rosaline who? Never heard of her...”
The truth is, if someone could have smacked some sense into the impulsive young lad, the perfect match was likely right around the corner. If someone could smack some sense into us gardeners, we’d possibly discover the ironweeds.
The genus Vernonia includes a ridiculous range of plants, all known by some variation of iron ― iron leaf, ironweed, iron plant, etc. Most of us would recognize one of the Kentucky natives as that 6 to 8-foot-tall, bright purple thing blooming in old fields and along roadsides right now ― Tall Ironweed, V. altissima (or V. gigantea if you want to stick your chin into that argument... )
With hundreds of species and a native range that includes most of North America, South America, Asia, and Africa, they vary from a South American species that tops out at about 3 inches tall to and, get this, a tree in the East Indies that grows to over 100 feet tall.
In North America, there are about 20 ironweed species, give or take a dozen depending on which taxonomist you happen to be arguing with on any particular day. Most are denizens of the bright and hot sun in just about any middle-of-the-road soil. They are known for their toughness (according to some, the origin of the “iron” part of the name, or is it the seed capsules that dry to an iron brown color when mature?) and their late summer blooms, mostly of an almost iridescent purple/violet color.
Ironweeds are incredible pollinator plants, regardless of species. Some have very tight pollinator relationships with specific butterfly and moth species. Others are broad pollinator generalists. But butterflies, moths, a whole host of native bee species, and even the occasional hummingbird are perfectly happy to stop at any ironweed for a snack.
Of all the ironweed species out there, there are two that we most often grow at Yew Dell for both gardens and meadow plantings.
What is Tall Ironweed?
This one is best described as one honkin’ big perennial. Even among the other tall ironweed species found across North America, this one is a beast. Topping out between 6 and 9 feet tall, it typically grows as a 1- to 3-stemmed plant that shoots straight up in the air, topped with screaming purple flowers that look like an 8-inch plate of slightly disheveled little purple daisies.
The tall ironweed makes a great back-of-the-border perennial that brings excellent late-season color to the garden. It requires little special care and has few pest and disease problems in the landscape. And little else in the garden perennial world can put such a sizeable exclamation point on the garden profile.
The biggest criticism of this species in a garden is its rather bare stems ― and at its tremendous size, those stems are quite noticeable. Of course, nestling it in with other more moderately-sized perennials can effectively mask those bare stems. It will spread a few seedlings here and there over time but they are easily managed.
One other species approaches this size that can be found around Kentucky. The New York Ironweed (V. noveboracensis) grows almost as tall as V. altissima but the Big Apple version sports a heavier flower mass and some downy hairs on the bottom of the leaves.
What is the narrow leaf ironweed?
On the other end of the size spectrum, there is one of our favorites among the garden ironweeds. The narrow leaf ironweed (V. lettermannii) is one of the most underappreciated sun perennials we can grow in sunny gardens. Forming a dense and fine textured mound to about 3 feet tall, it offers up the same iridescent purple blooms seen in the taller species, all through August and sometimes into September.
Constantly loaded with a long list of native bees, moths, butterflies, and even the occasional hummingbird moth, it turns into a hub of garden activity when in bloom.
But in reality, even if it didn’t have such a great flower at such a key time in the garden season, the foliage texture alone would make this a plant worthy of a spot in most gardens. Three-inch-long, almost thread-like leaves cover the stems in a rich green that stays looking happy right through the heat of the summer. Dry spells offer no challenge at all to this native of rocky and sandy, bone-dry soils.
A longstanding favorite selection of the narrow leaf ironweed, ‘Iron Butterfly,’ can be found around the plant world and probably accounts for the majority of this species offered for sale around the US.
If only Romeo knew of the ironweeds, his life would have been so much easier.
Paul Cappiello is the executive director at Yew Dell Botanical Gardens, 6220 Old Lagrange Road,yewdellgardens.org.
