© Janet Davis
Winter -– and the holiday season in particular -- is when housebound gardeners get to savor the exotic blooms of plants that are native to warm tropical and subtropical climes. But not all of these beauties take kindly to the hot, dry conditions of our homes. Here are some tips for growing a few favourites, and pointers on how to keep them around to cheer us for another season.
Azalea:
Azaleas enjoy sunny windows, but rather low temperatures of 10ºC-15ºC (50ºF-60F). Cool conditions are especially important at night. Keep well watered and carefully pinch off dead blooms without disturbing next year’s growth emerging just below. Around late May, or after frost danger is past, sink the pot into a lightly shaded spot in the garden. Water it regularly and feed monthly with a fertilizer for acid-loving plants, reducing to half-strength when flower buds appear. In late summer, bring your azalea indoors and place in a cool spot, 5ºC-15ºC (40ºF-60ºF),out of direct light, for two to three months, keeping just moist. Four weeks before blossoms are desired, move to a sunny, cool window and resume normal fertilizing and watering.
Amaryllis:
It always seems a
minor miracle watching the plump, onion-like bulb of an amaryllis (Hippeastrum)
thrust forth its sturdy stalk, strap-like leaves 
and
tall scape of breathtakingly beautiful flowers, all in a matter of weeks. But
such is the wonder of this South American native and why spectacularly-coloured
amaryllis bulbs are increasingly popular as holiday houseplants.
Plant your amaryllis in loamy potting soil in a pot just large enough to hold the bulb, with the top third exposed. If the pot has no drainage hole, add a layer of drainage material at the bottom to keep water away from the bulb. Water sparingly and place it in a sunny window at a daytime temperature of 15ºC-20ºC (60ºF-70ºF) – too little sun and the flower stalks and leaves will grow tall and leggy. When the stalk appears, increase water so the soil is consistently moist and rotate the pot occasionally. When the flower buds show colour, move the pot out of direct sunshine into a cooler spot to prolong flowering.
After blooming is finished, remove the withered flowers and move the pot into sun, keeping the soil moist and fertilizing every few weeks. In spring, sink the pot in a lightly shaded spot outdoors, continuing to water and feed. Amaryllis like to be rootbound, so repotting only needs to be done every three or four years. Water and feed. As summer ends, withhold water and fertilizer, allowing foliage to yellow if it hasn’t already done so. Cut off the dead leaves and bring the pot into a cool, dark place for two to three months. About six weeks before the new flowers are desired, remove about 1 inch (2.5 centimetres) of the soil, topdress with fresh soil, water well and bring into a warm, dark room until the first leaves appear. Move to a sunny window. Be patient with your second year amaryllis, if it doesn’t flower. Feeding is key, but it may just need another year of storing all the energy it needs to produce those sensational blooms. Read more on amaryllis.
Cyclamen:
Persian (or
florist’s) cyclamen is a challenging houseguest that needs bright, but
exceedingly cool and humid conditions in order to thrive. Place in a very
bright window, out of direct sun, and make sure temperatures don’t exceed 15ºC
(60ºF) in daytime; it likes night temperatures as low as 8ºC (45ºF). Keep it
well-watered, but perfectly drained; avoid watering the crown of the tuber to
prevent rot. A daily misting is beneficial.
Fertilize every two weeks with soluble 15-30-15. When growth slows and leaves yellow, stop 
feeding, reduce water and store in a cold room until
spring. When frost no longer threatens, place the pot in a shady covered spot
in the garden or on a cool porch where it’s protected from rain. Water very
lightly every two weeks. In August, re-pot the dormant tuber in sterilized
potting soil, leaving it a little exposed at the top. Place back in the shade.
By mid-September, new growth should be visible and your cyclamen can be
returned to its cool window. Resume normal watering, misting and fertilizing.
Flower buds will form only when sufficient foliage has grown.
Paperwhite
Narcissus:
Paperwhites are a cinch to grow, requiring only a short period in a coolish, dark spot before bringing them out to flower. Planted early enough and successively batch after batch in late fall, they can provide indoor blooms from November to late March. Pot them up in shallow containers containing either gravel, decorative marbles or potting soil. Start with a shallow layer of the planting medium, then add the bulbs (a crowded grouping gives a spectacular display) and fill in half-way up, just enough to anchor them. Keep them in a cool (10C or 50F), low-light area for 2-3 weeks until the roots are well-formed, then move them into a bright room to bring on the blooms. If the stems grow too tall, you can stake them with decorative branches tied around with twine or colourful raffia.
Poinsettia:
Euphorbia pulcherrima, or poinsettia, was named for Joel Robert Poinsett, the first U.S. ambassador to Mexico, who brought plants home to South Carolina in 1833. In the tropics, 10-foot shrubby poinsettias are pollinated by birds, and it’s the bright red, upper leaf bracts surrounding the tiny, yellow flowers which attract them and help them zero in on the nondescript blooms.
Today,
numerous dwarf cultivars have been hybridized, giving us not only miniature
versions of the original red species, but pink, white, peach and marbled
hybrids too. Poinsettias are very cold-sensitive and should be well-wrapped for
the trip home. They love bright light, but not direct sun (an east window is great).
Water when the soil feels dry to the touch, but don’t over-water.
Though I’d never be without a poinsettia during the holiday season, I refuse to fiddle around trying to make the same one re-bloom year after year. (I confess to committing poinsettia euthanasia sometime around Valentine’s Day, saying a fond farewell and gently placing it outdoors where it passes peacefully into the next life via compost heaven.) But if you’re so inclined, getting a poinsettia to re-bloom involves cutting the plant back in February, feeding it when new growth appears, moving it outside to a shady spot in June and continuing to feed, bringing it indoors in late summer, then observing a strict "photoperiod" of 15 hours of absolute darkness daily, from September 20th to December 1st. An old cupboard or closet is ideal for the dark part of the day, and a bright window or fluorescent lights are required for the remaining 9 hours. At the end of this period, your poinsettia can be brought into a bright spot where it will -- hopefully -- flower again.