I’ve been bustling around the garden for the last few weeks, getting all the tender plants in out of the cold. Tropical plants, such as all our common houseplants, need to move indoors by the time nighttime temperatures are consistently in the low 50s, weeks before the first frost would kill them outright.
This is a time of year when I’m making cruel decisions every day. A tuberous begonia may have been pleasant enough on the patio, but is it special enough to deserve houseroom to all winter? Nope. Compost. How many spider plants do I really need? Compost. Too bad all my friends have long since been saturated with my surplus houseplants.
All my plants get a severe inspection for lurking insects and a good bath with the hose before they come indoors. They spend a few days on the back porch, getting used to lower light, before they come all the way into the living room.
Some herbaceous tropical plants that are valuable in containers or in the garden, such as coleus, purple heart vine, plectranthus (Swedish ivy) and pelargoniums (often miscalled geraniums), are hard to overwinter unless you have a greenhouse. They get leggy and sprawly over the summer and if I cut them back they have a hard time recovering in dry, heated indoor air. It’s also a pain to find room for a bulky plant all winter when I mainly want it for the summer.
The solution is to take cuttings — clones, to give a particular set of genes a fresh start while the parent plant goes in the compost. Toward the end of each growing season I start taking 3- to 4-inch snippets with three or four leaf nodes from the growing tips of plants I want to save. Many, especially coleus, trandescantia, zebrina and plectranthus, will root in jars of water on my kitchen windowsill and then I’ll pot them up. Other cuttings I dip in rooting hormone and stick in small pots of sterile potting mix. I keep the mix moist for several weeks until a gentle tug on the stem confirms the cutting has grown roots and isn’t going anywhere.
Rooted cuttings will slowly put on growth but really take off in early spring when more sunlight makes it through the windowsills. By late March or early April, I’ll be pinching them back and rooting the snippets to use in the garden when the weather warms up.