Some of the most resilient and tough houseplants have a lot of mettle — they can endure inhospitable conditions and will thrive even when somewhat neglected. Is it any wonder that some of these plants have the names of metals in them? I call them “metal plants with mettle!”
Aspidistra Elatior (cast iron plant)
Probably the toughest of all the “metal” plants, the cast iron is a slow-growing foliage plant which will simply sit in any interior space — even a low-light environment — and not change in appearance for months. Its slow growth means that unlike many other plants, it will not soon become leggy and rangy.
This is an easy-care plant requiring little fertilizer (give it a low dose in spring and that will do). The cast iron plant needs to be watered sparingly as its slow growth means it has a very slow metabolism and will take up very little water. Although the plant will do best if the soil (which should have excellent drainage) is kept just moist, it will survive periods of drought, so if you forget to water it for a while it will survive. What it won’t survive is having its planting medium constantly sodden.
The long (30- to 60-cm) dark-green leaves are strap-like and only six to 10 cm wide, growing upright on fleshy thick stems. Like all foliage plants, it will look best if the leaves are cleaned regularly. Do this by wiping gently with a damp cloth starting at the bottom of each leaf and moving toward the end, while holding your hand under the leaf to support it so it doesn’t get bent or torn.
Begonia Masoniana ‘iron cross’
Although not quite as tough as the cast iron plant and requiring a little more TLC, the iron cross begonia is a stunning foliage plant for the interior. Its heavily textured light-green leaves each have a reddish-brown marking resembling an iron cross. The unique foliage is exquisite but iron cross begonias also produce pale-pink flowers held above the leaves on sturdy stems. Some people cut these off to encourage the development of more healthy foliage.
This begonia grows from rhizomes and therefore should not be planted too deeply in a very porous planting mix. The crown should be slightly above the top of the soil. Although it prefers moist soil, water is the main cause of an iron cross begonia not thriving or indeed dying. Do not overwater, provide excellent drainage and keep water off the foliage and crown. Watering by filling its saucer with water is the best method as the water is gradually absorbed and not concentrated in the top. Like all Rex begonias, iron cross likes high humidity so in the winter set the container on a pebble tray of water. It is usually propagated by leaf cuttings and often goes into dormancy in mid-winter so don’t be alarmed if many of the leaves shrivel and the plant declines. It will recover but hold back the water if this happens rather than increasing it.
Kalanchoe ‘Copper Spoons’
Another “metal” plant with vividly coloured foliage is a cultivar of kalanchoe called “Copper Spoons,” because its oval leaves are covered with fine cinnamon-coloured hairs that give the foliage its distinctive colour. It is a succulent so it can withstand drought but performs best when its soil is kept moderately moist. It likes humidity so a pebble tray might be used in the winter. Not a low-light plant, provide with as much direct sunlight as possible; in front of a south-facing window would be ideal. “Copper Spoons” likes a rich soil containing lots of organic matter and good drainage. Grown as a houseplant this shrub (in its native habitat) will grow about 30 cm high, but it can be pinched to control its height. If the plant is getting enough light it will produce bright-yellow flowers in late winter.
Pilea Cadierei(aluminum plant)
The aluminum plant is often used in dish gardens and terrariums. It is a small tabletop plant that looks good grown as a specimen in a small pot or combined with other similar-size plants. All Pileas (aluminum plant is a member of the large Pilea family) like high humidity and their planting mix to be kept moist (not wet). It gets its name from the big splashes of silver on its dark-green, rippled leaves. Bright indirect light suits this plant best and because it likes high humidity, it is often included in a grouping of small potted plants whose proximity increases the humidity around all the plants.
Many plants get their names from their appearance and all but one of the four “metal” plants I have described get their common names from their foliage. All four, however, have mettle — they are tough and resilient, suitable for any plant collection.