Houseplants are quick to tell you when they need help. They display discolored leaves, drooping stems, and little or no growth. That usually gives you enough time to make things right.
“Plants send signals simply by the way they look,” said Dawn Pettinelli, an Extension educator at the University of Connecticut. “If they aren’t getting enough light, the leaves will yellow or turn brown and they’ll be slow to develop.”
Off-color leaves also can be the symptom of root problems, insect infestations, irregular soil moisture, or unsuitable light conditions or temperatures.
African violets, one of America’s most popular houseplants, don’t like to be cold but also get stressed when it’s too warm. “They’ll start wilting if they’re chilled and they won’t bloom if they’re hot,” Pettinelli said. “Their buds will fall off.”
A good way to rejuvenate many kinds of tired houseplants is by pruning or giving them what some growers dub “horticultural haircuts.” Pruning serves a variety of functions, including shaping, removing dead matter, and cutting back to reduce stem loads and keep the plants from sagging or drooping, said Diana Alfuth, a horticulturist with University of Wisconsin Extension.
But don’t prune too soon.
“Pruning can be helpful but pruning causes growth, so it’s best done in late winter when the days start getting longer and the plants become more active,” Alfuth said in an email. “Pruning then results in strong new growth. Pruning is helpful to keep a plant bushier or to rejuvenate a plant, especially if it has vining type growth.”
Slow-growing or tree-type houseplants are less tolerant of major trimming, she said. Avoid pruning palms, pines and orchids.
Pruning also provides an opportunity to take cuttings — segments from the stems, leaves or roots — to develop new plants.
Some houseplants are more tolerant of neglect and need less maintenance than others.
“Succulents are great because they can go without water for long spells, and they grow slowly so rarely need pruning or re-potting,” Alfuth said.
A houseplant’s diet is important and so is the timing of fertilizer applications.
“Houseplants should not be fertilized during winter when days are short,” Alfuth said. "Fertilize in late winter as days get longer and plants wake up and will need fertilizer to put on growth during spring.”
Houseplant maintenance doesn’t need to be confined to spring cleaning. “It can be done any time of the year, but a good way to remember it is by making it a New Year’s resolution,” Pettinelli said.
Don’t forget to dust.
“When plants start touching the floor, they start collecting dust,” Pettinelli said. “If covered with dust, photosynthesis is reduced and the plants start losing some of their chemical energy for growth.”
Be careful not to overwater, which is one of the leading causes of houseplant losses. "Plants lose oxygen when they get too much water,” Pettinelli said. "Especially the roots. They’ll drown.”
Check to see if your plants are root-bound and need re-potting. If so, then buy larger containers and fill them with loose potting soils mixed with perlite or peat moss. Be sure the pots have holes cut in the bottoms so any excess water can drain out.