The genus Impatiens is quite familiar to most gardeners. From beds and borders of bedding impatiens, use receding and then rebounding some in recent years with the scourge of downy mildew disease, to the ever-more colorful types of New Guinea impatiens and their genetic resistance to downy mildew: these flowers are garden staples. There are also our native impatiens, the orange-flowered Impatiens capensis and the yellow-flowered I. pallida, known as jewelweed or touch-me-not.
Mature fruits of touch-me-nots found at Holden Arboretum explode when "peenched"
Jewelweeds have tell-tale gem-shaped fruits, water that beads on the leaves, leaves temporarily wilting like other impatiens during the heat of the sun, and fruits that explode upon touch to expel seeds outward from the mothership. Twice in the woods and roadside of Secrest Arboretum I have also seen a salmon-flowered variant of our native jewelweed, a product presumably of a random mutation.
So, imagine my wonder when while on Mackinaw Island in Michigan for a gardening conference recently I noticed a tall plant with narrow leaves and delightful pink and white flowers in flower beds looking up toward the Grande Hotel. At first, I thought it was a type of snapdragon or other plant in the Scrophulariaceae with its unusual mouth-agape blossoms. Then the jewel-like fruits on the plants came into focus. A pink jewelweed?
A lovely pale pink petal of Himalayan jewelweed at the Grande Hotel
Jason's trusty cell-phone helped with identification of Himalayan jewelweed
Secrest curator Jason Veil had not seen this flower before either, but his cell-phone was handy. It was Impatiens glandulifera, the Himalayan jewelweed or Himalayan balsam (impatiens being in the Balsaminaceae family). We were all excited about learning of this new (to us) garden plant – a pink touch-me-not. I must write about it, I thought. Alas, within the day, our horticulturist interest waned as we read on that this Himalayan native annual plant is now present across much of Europe and North America after introduction as an ornamental, with one source even labeling it as one of the most invasive species in the world.
I don’t know about that, but clearly it is invasive. Who knew? Not us. Our perspective changed from something we did not know of to admiration to not planning to further the spread in a matter of hours. Then a few weeks later, in the Denver Botanic Gardens, we noticed beds of two more Impatiens species, the yellow-and-white-flowered I. bicolor and the lavender-and-white-flowered Impatiens balfourii, both from India. Our impatiens knowledge continues apace.