Every time I write about houseplants I get e-mails from readers asking how to care for their sick plants. Problem is, I’m not an expert on caring for houseplants. I have trouble keeping them alive because I forget to water them.
I have experience with gardenias because they were my mom’s favorite plant. Unfortunately, gardenias are not easy plants to grow indoors in Michigan because they’re pretty fussy about their surroundings. And if they don’t get what they want, they drop their leaves and flower buds. Bummer.
Daytime temperatures of 70 degrees and 60-degree nights are preferred, and they like bright filtered light. In Michigan in winter, a room with south-facing windows is best. But place the plant too close to a window and it may suffer from a chill when the temps dip or from a sunburn on those times when the sun shines all day. Mom kept hers on a table about four feet from the windows.
Gardenias like moderate humidity, but in winter, forced hot-air heat sucks out the humidity, and the air is often dry as a desert. Regular misting, often recommended, does little to help because the water dries in a matter of minutes. Also, continually wetting the leaves sets the plants up for fungal disease. The recommended method of increasing humidity around the plant is to place the pot on a tray of pebbles filled with water, making sure the base of the plant pot is above the water line. A small humidifier is also a good idea.
The black spots on the leaves of Al’s gardenia are probably sooty mold growing on the sugary residue from white flies. Spraying with a pesticide every three days till the bugs are gone will cure that ill.
My mom’s secret to enjoying her favorite flowers was to buy a gardenia that was in flower and sporting lots of buds. She watered often enough to keep the soil moderately moist and fertilized with an acid-based fertilizer every four weeks. Mom enjoyed the fragrant flowers that persisted for several weeks, and when the plant bloomed out she thanked it for the lovely display and tossed it.
If you have other houseplant questions, call my plant guru Lisa Steinkopf, who grows some 400 houseplants in her home greenhouse. Lisa is more than happy to help you out, so call her at Steinkopf Nursery in Farmington Hills, (248) 474-2925, or better yet, e-mail her at firstname.lastname@example.org.