Experienced gardeners happen upon unfamiliar plants from time to time. One reason to visit garden centres during the winter, other than to enjoy the wonderful ambience, is to scout out the potted plant section in search of the unfamiliar. One such plant that I came upon was the calathea.
Calatheas are rated as “challenging” houseplants in a couple of my reference books. The rating is probably due to the fact that they like moisture – both in their planting medium and in the air around their leaves. Plants that demand high humidity levels are often difficult to keep looking good in the rather dry indoor environments of our homes during the winter. With some care, however, such plants can be kept healthy and attractive.
The calathea is part of a large group of tropical foliage plants whose large decorative leaves seem to rise directly from the rootstock but which in fact are normally connected to short stems. They do on occasion produce blooms in the form of spathes, similar to anthuriums and spathiphyllums.
The decorative foliage of the calathea is its most attractive feature. The upright leaves are colourfully patterned on their upper surfaces and maroon in colour underneath. Most leaves are upright enough and have a bit of a twist to them so that both the surfaces and the undersides are visible on many of the leaves.
Close-set colourful lines, patches of darker or lighter colour, and contrasting leaf margins are some examples of the unusual colouration of calathea foliage. It is not surprising that these plants are closely related to the maranta, or prayer plant, which has similar foliage variegation.
Calatheas prefer medium light but they should receive no direct sunlight or the bright colour of their leaves will be spoiled. Average room temperatures suit them just fine as long as the air is not too dry. During the active growing period calatheas must be watered thoroughly and regularly. The planting medium must not be allowed to dry out and in fact must be kept consistently moist.
Also when in active growth calatheas should be fed every two weeks with a standard all-purpose fertilizer. One of the best to use is a soluble fertilizer used at half-strength. These plants are heavy feeders and if a peat-based planting medium is used, they must be fed regularly without fail. During rest periods the surface of the soil can be allowed to dry out a bit between waterings and the amount of fertilizer can be reduced. Placing the pot on a pebble tray will increase the humidity around the plant.
A mature plant can be repotted and divided – a task that is usually necessary every couple of years. This job is best done in the spring or early summer. The clumps can be divided and small pieces, with some root attached, can be planted in smaller pots to form new specimens. As the plants grow, they can be potted up into larger pots.
If you have space for another foliage plant that will create quite an impact, and you like a challenge, you might try a calathea. It will add an exotic and colourful focal point to your interior landscape.
– Albert Parsons writes from Minnedosa, Manitoba