Popular Houseplant Undergoing an Identity Crisis


This blue green, small-leaved pilea is a common houseplant … but what is its botanical name?

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!


So-called Pilea glauca, but more likely P. libanensis.

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


With blue-green leaves and thin reddish stems, the gray artillery plant is quite charming.

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.


It looks great in hanging baskets.

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!

Laidback Gardener Tip of the Day


A Fireplace Garden Makeover

septembre 28For a long time now (about 15 years), I have been growing a mini garden in the fireplace of my basement office, lit by a fluorescent lamp installed inside the chimney, out of sight. However, I was becoming less and less satisfied with the results. Over time, a peace lily (Spathiphyllum) I had planted when it was just a little sprout had become a monster and had slowly eliminated, with its dense shade, almost all other plants except a creeping fig (Ficus pumila) that saved itself by climbing up the fireplace’s brick walls. So yesterday I set out to create a new mini-garden, using this time, I hope, plants that will really remain dwarfs.

I actually prepared for this project over the last few months, picking up materials over my various garden tours. I harvested stones and bits of driftwood from the beach in Matane, Quebec in July. During my trip to Longwood Gardens in August, I bought “real terrarium plants” (the ones sold for that purpose in my area are generally juvenile forms of plants far too big for my needs!). Two weeks ago, while in the Brooklyn Botanic Garden shop in New York, I bought a bag of “tropical moss”, hoping that once moistened it would come back to life as the label on the product promised. If not, it will at least fill in a few blank spaces until my other plants start to grow. So yesterday, on my first full weekend at home since March (I lead a busy life!), I chopped up the overly dominant peace lily and removed it from the old garden piece by piece (I did not want to disturb the roots of my creeping fig, which is to remain a backdrop for my new garden, by trying to dig the plant out all at once). Then I added moistened potting soil, decorative stones, pieces of wood, and finally, mosses and  my new little plants. The plant list includes a miniature sinningia, several small ferns, dwarf begonias, a few pileas (Pilea microphylla and P. glauca), a round-leaf peperomia (Peperomia rotundifolia), a tiny syngonium (I know, I know: it will one day outgrow its space and have to be removed, but it is so cute right now) and, as small tree, a eugenia (Syzygium myrtifolium). Afterwards I watered gently to settle the roots, then mopped up. It remains to see which plants will thrive and which will not, and then make adjustments. Still, I’m very satisfied with the results so far and figure this new fireplace garden should be good for another 15 years.