What triggers bloom in houseplants? Plants bloom if they get good care — the right light, temperature, water, food, and growing medium — but the details depend on the particular species. If you can get one African violet to bloom, you’ll be successful with any of them. But if you treat your kalanchoe the same way, it will probably never flower.
The goal is to provide an environment that’s as close as possible to conditions in the plant’s native home. Some plants, for instance, have learned to face adversity — periods of cold or dry — by going dormant for a while. For many, going through this dormant period is required to trigger blooming. In the wild, plants recognize when to go dormant by being sensitive to shorter days, lower temperatures, or reduced rainfall.
In a house, dormancy is induced naturally by shorter days, or by your withholding water or putting the plant in a cooler spot. Growth slows, and the plant needs less fertilizer and water. When days lengthen and become warmer, or you resume more generous watering, you complete the cycle and flowering begins.
Other plants come from environments where light, temperature, and rainfall are about the same all year. Those plants can grow and flower anytime, so they rarely need a dormant period to induce flowering. Since they are always growing, the amount of light, fertilizer, and water you give them throughout the year remain constant. The amounts depend on the species.
Zonal Geranium (Pelargonium x hortorum)
Most geraniums are easy keepers, but the zonal ones are the best survivors. They have round leaves, usually with concentric stripes of colors around the edges. And if they are given a combination of cool temperatures and strong sunlight, they will repeatedly produce large flower clusters. The most important tool for nurturing them is a pair of shears; geraniums tend to become gangly even when conditions are perfect, and they can get extremely gangly if light is scarce. Frequent cutting back will keep them bushy and healthy.
African Violet (Saintpaulia)
My Mom’s favorite, today’s African violets are the most popular of all flowering houseplants. They trace their heritage to several species collected in East Africa in the late 19th century, but their appearance today derives from years of intensive hybridization among only a few of the species. The original blue and purple African violets are still happily blooming, but most have yielded the spotlight to new color tones. Modern violets also appear in white (the touchiest sort to grow), all shades of pink, burgundy, and even crimson. Generally, African violets need abundant filtered light. In summer, however, move plants away from any direct sun to where they will receive less intense, indirect light only. Violets like the same comfort level you do: average room temperatures or a little warmer in the day and a few degrees cooler at night. Keep the humidity high around your plants by placing them on a humidity tray, but never allow them to sit in water or the plant will die from fungal rot. Whenever the top half-inch of soil feels dry to the touch, add enough water to make it evenly moist. There are many, many websites dedicated to the care and nurturing of African violets.
Peace Lily (Spathiphyllum)
Hasn’t everyone tried to grow a big, beautiful, flowering Peace Lily received as a gift? The Peace Lily tops the list of plants that provides beautiful foliage and flowers AND is easy to grow. The plant thrives indoors and blooms reliably with minimal attention. White flowers with a stiff yellow center (similar to those of a calla lily) appear nearly continuously amid the large, dark green, oval leaves. The plant needs low to medium light (never direct sun) and average indoor conditions. Its tropical foliage looks best, however, if you raise the humidity around it by setting it on a humidity tray. Moisten the soil evenly when the top inch feels dry to the touch; reduce watering when room temperatures fall below 70ºF, and never expose a plant to conditions below 55ºF.
Why should you let Mother Nature dictate when you can enjoy gardening? There are hundreds of lovely houseplants that need care and love, and are currently sitting at your local nursery or garden center waiting for you!