Houseplants seem to be in vogue again, which is encouraging because they have a way of bringing the plant world into the hearts of those who need it most: urban dwellers, office workers and people generally short on terrain.
The image of these plants suffered for years simply because they were popular in the 1970s, the decade of sallow plaids, wide lapels and hairstyles that will forever remain inexcusable.
Fortunately, today’s champions of indoor plants are too young to know that dark decade, and their enthusiasm for creating indoor gardens extends to succulents, air plants and that other maligned floral relic, the terrarium.
I like all of those interior adornments, but it is the more traditional houseplants that I find particularly endearing.
In advance of the outdoor spring craziness around the corner, we should attend to our houseplants now.
Life indoors is a challenge to a plant. The principal environmental woes are rooms that are too dim and too dry. The greatest risk the human owner poses to the plant, you will read, is overwatering. This is true, but I’ve seen a lot of damage from underwatering. This, in turn, is linked to how people house such things as dracaenas, crotons, sansevierias, spider plants and the rest.
If your colleagues are like mine, they have their plants in pots that do not drain. To avoid waterlogging the roots, they tip half a cup or so once a week into the soil. This isn’t enough, and it’s not the best way to do this.
The optimum arrangement is to have the plant in a thin, plastic, well-draining pot that is then placed in an outer, more decorative cachepot that doesn’t drain. When it comes time for watering, remove the plant in its growing pot, take it to a sink and soak the soil until the water drains from the bottom. Let the pot drain for a few minutes and then return it to the cachepot.
An alternative is to have the plant in a single decorative pot that drains. It should still be carted to a sink for its root soaking and returned after draining.
By the way, the practice of placing a couple of ice cubes to melt on moth orchid roots is ill advised, in my view. Apart from the chilling effect, the cubes equate to an ounce or so of water, which isn’t enough to hydrate the growing medium of bark mix or moss. (Of those, I much prefer bark mix, which is almost impossible to overwater, though it should be changed annually.)
For houseplants generally, a good watering will last at least a week. The books tell you to water less frequently in winter, to keep the plants in a resting mode, but heated interiors tend to be woefully dry. Check the soil with your finger and water again when the top inch or so is dry.
Most houseplants are beginning to stir into life, drawn from their winter dormancy by the lengthening period of daylight. Some plants can go three or four years without repotting, but I find most benefit from an annual replenishment in advance of their spring growth spurt.
We should do this for several reasons that all come down to the fact that plants were never meant to grow in pots, even tree dwellers such as moth orchids.
After a year or two, the original light, fluffy potting mix breaks down and compacts, creating the risk of holding too much water and too little air. Fertilizer salts build up. In addition, the roots will fill the pot and need freeing. If they get too congested, they completely displace the soil. The plant cannot keep abreast of its needs for moisture and nutrient.
How do you replenish the soil? It’s a messy process - I use a workbench, lots of newspaper sheets and a big trash can nearby. By removing the plant from its pot (not always easy), you will quickly determine the state of the root system. Tease the old soil from the roots, untangle them and remove dead or desiccated ones. Typically, you want to put a congested plant in a pot about two inches larger, using fresh potting mix (not topsoil). After a good soaking, I feed the plant with a weak solution of fertilizer as a tonic.
Each plant is different - you can’t know how one is doing until you get a good look at the roots. A couple of recent repottings drove this home for me.
The first was of a colleague’s dracaena, which looked robust and leafy but was suffering because it had been planted in a single container that did not drain. Its keeper emptied a bit of water into it every few days. After a year in this pot, the soil had broken down, the fibrous roots were growing on the surface, and the trunk had sunk into this morass.
She had used a potting soil at first, but one in which earthworms had infiltrated, and the worms probably hastened the loss of growing medium. Replenished, the dracaena now resides in its own draining, plastic pot an inch or so smaller than the original, which functions as the outer container.
In fixing it, a lot of the threadlike roots were lost, and I had to rig a framework of bamboo canes to support the plant until it can grow more anchoring roots.
The second plant was my own, a clivia that has begun to grow its spring leaves and flowers. The standard advice is to wait until after flowering to repot it, but it was sharing a pot with its offpsring and was crying out to be divided. Besides, by the time it finishes blooming in May, I’ll be in the thick of the garden and won’t be fussing with houseplants, except to place them outdoors.
Most houseplants hate the direct sunlight of the exposed outdoors but will benefit from a summer spent outdoors in a shady, protected area.
The clivia was placed in a decorative ceramic pot that drains, and sits on a saucer to protect the floor. Its potbound roots were unfurled, groomed and given a fresh universe of potting mix. The soil was well soaked and then given a liquid feed. My instincts tell me that it won’t miss a beat.
Gardening tip of the week:
Ornamental grasses that have been left uncut through the winter should be cut back in advance of new growth. Remove last year’s blades at two to three inches above ground level. Sharp hedge shears will make short work of tough grass stems. Shredded stems can be used as a mulch or added to the compost pile.