Is it possible that a plant could be distributed throughout the world without ever having been identified, at least botanically? In fact, this sort of thing does happen occasionally and one plant that is currently in that situation is a small pilea with creeping reddish stems and tiny round blue-green leaves. It seemed to come out of nowhere early in the 21st century and is now widely grown around the world, both as a houseplant and as an annual for outdoor containers, even a groundcover in outdoor gardens in the tropics, yet no one seems to know its botanical name.
You may know this plant as Silver Sparkles plant, gray artillery plant, gray baby tears or pilea ‘Aquamarine’. Also, you’ll often see it sold under what would appear to be a botanical name, Pilea glauca. However this name is what is called a nomen nudum in botany: a name that was never been published according to proper botanical procedures, that is in a scientific publication with a corresponding description. It would appear that a grower in Florida began selling this plant under the name Pilea glauca because of the glaucous color of its leaves and the horticultural community simply accepted the name without further verification. Sorry, but that is not how things are done in the world of botany!
You’ll also see this plant sold under the name P. glaucophylla (it means glaucous leaved) and if you do a bit of digging, you might at first think you’d found the correct name, as there is a true P. glaucophylla, a plant discovered in Colombia (although the information associated with the name P. glaucophylla claims, for some reason, that it comes from Vietnam). There’s just one catch: the true P. glaucophylla is an upright plant 20 inches (50 cm) tall and above with oblong leaves 5 to 6 inches (10-15 cm) long. Absolutely nothing like the small-leaved creeping pilea in question!
David Scherberich, a botanist at the Botanical Garden of Lyon, believes this plant to be P. libanensis, a species native to Mt. Libanon near Guantanamo, Cuba. Still, the name P. libanensis has not yet been confirmed for this plant. The plant currently being grown would have to be compared to a specimen in a recognized herbarium and that doesn’t seem to have been done.
So our little pilea, which I’ll call the gray artillery plant from here on, is still without a formal botanical name … but that needn’t stop you from growing it!
Easy to Grow
The gray artillery plant does best in medium light, though it can be acclimatized to full sun. Grow it in the potting or container soil of your choice. Water it well, making sure to moisten the entire root ball, then repeat when the soil is dry to the touch.
It doesn’t seem to need a lot of fertilizer. Just use your favorite kind at a reduced dose during its growing season, usually from March to September.
The gray artillery plant tolerates the dry air so typical in our homes in winter, but prefers much higher humidity, 50% if possible. 70% would be even better.
Since this plant comes from the tropics, it will grow best at warm to hot temperatures. One source suggests a minimum temperature of 55˚ F (12˚ C), but I suspect that has not actually been tested: most tropical plants can tolerate temperatures close to freezing for short periods.
This plant is a snap to multiply: just press a few sections of stem into a moist growing mix and they will soon take root.
Typically the gray artillery plant is grown in hanging baskets or in mixed containers, as it elegantly cascades down over the pot’s lip. Don’t hesitate to pinch back its creeping stems for a denser effect. It also makes a great groundcover for dish gardens and terrariums and is used in three-dimensional mosaics and green walls.
A Curious Habit
This plant, along with its even smaller-leaved cousin, P. microphylla, are “artillery plants.” When you water them, the stamens of their tiny flowers, which otherwise go unnoticed, suddenly burst open, throwing pollen into the air like fireworks. Try and you’ll see: it’s quite surprising!
There you go: a plant with no valid name and yet very real and even easily growable. Who knew!