By Cindy Haynes
Iowa State University Extension
We all like the cheer of the holiday season to last as long as possible. Holiday plants are a reminder of the holiday season and the cherished time we spent with friends and family. Keeping these plants looking good throughout the holiday season and beyond is not as difficult as you might expect.
Poinsettia is the most popular holiday plant. In fact, so many are sold this time of year that it is the most popular potted plant for the entire year in the United States. With recent advances in breeding and selection, some poinsettia varieties will bloom for several weeks – if not months – indoors. The trick to keeping them looking good indoors is consistent water and light. Place them near a window so they will receive indirect sunshine. If they do not receive enough light, they will quickly loose their leaves. Secondly, water them frequently, but only when the soil is dry to the touch. Then, water well until water drains out of the bottom of the pot.
The hardest part of growing a poinsettia is getting it to rebloom for the next holiday season. Plants must remain healthy and growing throughout the year. In May (after the last frost), plants should be placed outside in shady locations. At this time, the plants should be cut back to force more branches and a compact habit. Plants must be watered and fertilized regularly throughout the summer months.
In September, plants must be brought indoors before a frost, as they are extremely sensitive to cold temperatures. They must be placed in warm, sunny locations indoors during the day.To initiate new blooms and bract (colorful leaves) formation, poinsettias require short days or long nights. So in early October, plants must be placed in a dark location (closet, unused bedroom, etc.) or covered with a box from 6 p.m. until 8 a.m. the next day. During the dark period, the plants can see no light (this means no peeking!), even for short periods, as this will delay flower initiation. At 8 a.m. plants are removed from the dark location and given plenty of sunlight to properly photosynthesize.
This process of transferring a plant between dark and light locations is repeated every day for a minimum of 6 weeks, sometimes 10 weeks, or until the bracts become colorful. Once the bracts are colorful, the plants no longer need the extended dark periods.
Because the process of reblooming a poinsettia is so time-consuming, I usually buy a new poinsettia every year. Greenhouse growers won’t mind if you decide to compost your poinsettia in spring and forgo the effort of growing and reblooming yours for next season – I promise. This is also the reason so many poinsettias are sold every year during the holiday season. There are many people like me that prefer to buy new ones every year.
Holiday cactus should not be thrown out after the holiday season. This is a wonderful houseplant that can last for decades indoors. It too requires short days to initiate blooms, but it is more forgiving than poinsettia. Place plants in a sunny window during the winter and spring. In late spring transfer plants outdoors to a shady location and water and fertilize as needed.
Bring plants indoors before frost and in early October place plants in a window of a guest bedroom or other room that is rarely used in the evening. Generally the natural photoperiod or night length for a few weeks will be sufficient to initiate blooms. Try not to have the lights on for long periods during the first few weeks as this can delay flowering. Holiday cactus prefer drier soils than poinsettia, but not as dry as a typical cactus. It is especially important not to let plants dry out completely when setting flower buds, as they will drop quickly in response to drought.
Amaryllis is another keeper for the holiday season and beyond. This bulb is often forced into bloom during the holiday season. After plants are done blooming, remove the flower stalks. Place the plants with leaves in sunny windows until they too can be transferred outside during the summer months. Water and fertilize regularly until late August or early September. At this time, allow plants to dry out gradually until the leaves yellow and die. Amaryllis require a dormant period to rebloom, so the bulbs are dormant at this time – not dead. Place the containers with dormant bulbs in a dark location for a couple of months. Check on them occasionally. When new growth appears at the tip of the bulb, it is ready to be placed in a sunny location and watered again. In a little more than a month, new blooms will appear.
It is easy to keep the holiday spirit by simply keeping the holiday plants alive and reblooming year after year. For more how-to information on each of these plants, check with your local county extension office or online at www.extension.iastate.edu/store.