Pilea cadierei
The aluminum plant, Pilea cadierei, is an evergreen herbaceous perennial that grows outdoors in part shade in USDA Hardiness Zones 11 and 12, and indoors in bright indirect sunlight in all locations.
It has a shrub-like, clumping growth habit and is appreciated for having texturally rich foliage that is green with silver markings.
P. cadierei is one of approximately 600 types of non-stinging Pilea species in the Urticaceae, or nettle family that contains stinging nettle and clearweed.
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In this article, we discuss all you need to know to cultivate a showy aluminum houseplant of your own.
Here’s what’s in store:
Also known as watermelon pilea, the silver-streaked foliage of P. cadierei resembles the striping on the rind of the classic summer melon.
It’s an intriguing pattern. Between the leaf veins there are raised areas, and the fact that they are highlighted with silver makes them stand out strikingly.
Quick Look
Common name(s): Aluminum plant, watermelon pilea
Plant type: Herbaceous evergreen perennial
Hardiness (USDA Zone): 11-12 (outdoors)
Native to: China, vietnam
Bloom time / season: Summer
Exposure: Bright, indirect sunlight, can tolerate low light
Soil type: Organically rich loam, well-draining
Soil pH: 5.0-6.0, slightly acidic
Growth Rate: Fast
Mature size: 6-9 inches wide by 9-12 inches tall
Best uses: Houseplant, ground cover outdoors
Taxonomy
Order: Rosales
Family: Urticaceae
Genus: Pilea
Species: Cadierei
The leaves have serrated margins, and are a cross between elliptical and ovate in shape, as some are pointed, and others are more rounded.
The leaves feel waxy, and the stems are fleshy, like those of a begonia or succulent species.
The flowers are nondescript with a greenish-white color. They grow in cymes, which are flat-topped inflorescences, or clusters.
In their natural habitat, blooms appear in spring and summer, but they are rarely seen on houseplants.
With a manageable mature height of nine to 12 inches and a spread of six to nine inches, this little cutie is well suited to indoor gardening, especially in small spaces where it can shine as a standalone showpiece.
P. cadierei is native to China and Vietnam, where it grows as a ground cover over the jungle floor, thriving in shade and dappled sunlight with an abundance of heat and humidity.
P. cadierei likely made its way west as one of a host of tropical specimens destined for study, cultivation, and introduction to the burgeoning ornamental plant market of the early 20th century, when imported palms graced Victorian parlors.
And although it is a relatively short-lived species that is unlikely to last more than five years, it’s so easy to propagate from stem cuttings that you can enjoy it well into the future.
How to Grow
Keep your plant in a room with temperatures between 60 and 75°F, and provide bright indirect light.
Direct sunlight, especially through a windowpane, can scorch foliage and should be avoided.
Use an organically rich, loamy potting medium that is light and airy, moisture retentive, and well-draining. A pH of between 5.0 and 6.0 is ideal.
Aluminum plants thrive in soil that is kept evenly moist, but not waterlogged.
Water the plant before the soil in the pot dries out. Take care to water the soil, not the leaves, as wet leaves are prone to diseases and rotting.
If your home is especially dry, you may want to increase the relative humidity for your aluminum plant.
You can do this by setting the plant on a tray of pebbles with water or by clustering a group of houseplants together.
At planting time and each spring, feed with a well-balanced liquid fertilizer per package instructions.
Continue to feed monthly during the growing season to stimulate the production of healthy foliage.
In autumn, growth slows down, and a period of dormancy begins. Reduce watering and suspend fertilizing until the following spring.
Note that if bright indirect light is unavailable, a good grow light is a viable option. Please see our article on grow lights to choose the best model for you.
Where to Buy
It’s easy to fall in love with a watermelon pilea when you start with a quality product that has been well-cared for during its nursery days.
Find aluminum plants now from BubbleBlooms via Amazon in four-inch pots.
In addition to full-size plants, there is a dwarf variety. P. cadierei ‘Minima’, with an especially petite height of only eight to 10 inches. It has the same rich green and silver leaf markings, and cultural requirements.
Maintenance
This is a moderate amount of maintenance involved in caring for your aluminum plant during the growing season.
In addition, this is a fast-growing species that requires regular pruning during the growing season to maintain a compact form.
The removal of dead and damaged leaves as well as leggy stems optimizes visual appeal.
Always sanitize pruners in a 10 percent bleach solution (one part bleach to nine parts water) before and after use.
Make cuts just above a pair of leaves to stimulate upward foliar growth.
If you are going to use the pruned stems as cuttings to propagate new plants, recut them just below a pair of leaves to stimulate root growth below the leaf node.
To encourage bushier growth, you can wash your hands and use your thumb and index fingernails to periodically pinch off the top inch or two of fresh spring and summer growth.
Propagation
To start your own watermelon pilea, you’ll need to take a stem cutting from an existing plant or purchase a new one from a nursery that you can transplant to your own pot as desired.
First, let’s talk about taking cuttings and rooting them in either water or soil. Then we’ll move on to nursery pots.
From Stem Cuttings
The best time to take cuttings is during the growing season in spring or summer.
To take a cutting from a stem, start at the growing tip and measure down about three inches.
Use clean scissors to cut cleanly across the stem about an eighth of an inch below a pair of leaves.
Snip off the lowest leaves so you’re left with a length of bare stem at least two inches long, with the top leaves intact.
Choose a four- to six-ounce container and sanitize it with a 10 percent bleach solution (one part bleach to nine parts water), then thoroughly rinse and dry it.
Place the stem in the container and fill it with two inches of water.
Set the container in a location with bright indirect sunlight and a temperature between 60 and 75°F.
Change the water every few days to keep it fresh.
You’ll see fragile white roots sprouting from the bottom of the stem in a few weeks.
In another week or so, it’s time to transplant the cutting to potting soil.
Choose an attractive, well-draining container that can accommodate bushy dimensions of nine to 12 inches tall and six to nine inches wide.
Fill the pot three quarters full with your choice of potting medium and make a one-inch-deep hole.
Gently insert the rooted stem into the hole and tamp the soil around it securely, then water well.
If you wish to start your cutting in soil, you can dip the cut end in rooting hormone powder, then set the cutting one inch deep in a starter pot filled three quarters full of potting medium.
Maintain even moisture. New growth is evidence of successful root formation. At this point you can pot it up into a larger container.
From a Nursery Pot
When you purchase a potted specimen, you may wish to repot it in a container of your choice.
Choose a container that will accommodate the mature dimensions of the plant, and ensure that it has drainage holes in the bottom.
Gently unpot the plant and loosen the soil and roots.
If they are tightly coiled, or root bound, you can snip the lowest roots to loosen them and flay them outward to encourage them to spread out.
Place the entire contents of the original pot in the new container. Set it so the plant is at the same depth in the new pot as it was in the old.
Fill in with organically rich potting soil as needed. Ideally, you should leave one inch of space from the rim of the pot to the soil surface to allow for watering without overflowing.
Tamp the soil down to secure the plant in the new pot, and water well.
Pests and Disease
With bright, indirect light, moderate watering, rejuvenating pruning, and monthly fertilization, your watermelon pilea will enjoy good health and be able to fend off many ailments.
However, houseplants in rooms that are too hot and dry may succumb to pests like aphids, mealybugs, or spider mites.
Caught early, a firm dousing with the kitchen sprayer followed by a treatment with organic insecticidal neem oil should do the trick.
Getting rid of these pests is a must, as they are carriers of plant diseases, and their sap-sucking can cause extensive foliar damage.
When a pest infestation can’t be controlled, as a last resort, you can cut all the stems to the crown and discard them in the trash.
With a nourishing dose of liquid houseplant fertilizer and regular watering, the stems may regrow.
The following diseases are common to P. cadierei:
- Anthracnose (Colletotrichum spp.)
- Myrothecium Leaf Spot (Myrothecium roridum)
- Pythium Root Rot (Pythium spp.)
- Rhizoctonia Aerial Blight (Rhizoctonia solani)
- Xanthomonas Leaf Spot (Xanthomonas campestris)
- Southern blight (Sclerotium rolfsii)
Most of these are caused by fungal pathogens or water molds (oomycetes). Symptoms can be hard to distinguish, and most spell disaster.
Only Pythium root rot and Rhizoctonia aerial blight may respond to fungicidal treatment.
The bottom line is this: When plants are too hot and dry, they may succumb to sap-sucking pests.
And when the foliage stays wet, it becomes a breeding ground for pathogens, most of which cause diseases that are are incurable.
It’s important to be proactive!
Avoid both under- and overwatering, and always water the soil, not the leaves, to prevent moisture buildup.
A Pleasant Little Companion
You’re going to love not only the attractive form of watermelon pilea, but the versatility as well.
It makes an elegant addition to your houseplant collection, and a great home office companion as well.
With organically rich, well-draining potting medium, a warm room, bright indirect light, monthly feedings, and consistent moisture, you’re well on your way to success.
Don’t you think it’s time to add P. cadierei to the to-do list in your handy garden planner?
Do you grow your own watermelon pilea at home or work? Tell us about your little plant buddy in the comments section below.
If you enjoyed reading about growing this tropical species indoors, we recommend the following houseplant guides next:
