Contrary to a popular myth, poinsettias are not seriously toxic to people or pets. At most, they are mildly toxic to cats and dogs who ingest the plant material. If grown as a landscape shrub in warm climates, poinsettia requires a sunny location and well-drained soil. Frequent pinching back of the stem tips will ensure seasonal color in winter.
Light
Poinsettia do best when placed in bright, diffused sunlight, so place your plant near a sunny window where it will receive at least six to eight hours of diffused light per day. Although the plants can survive with fewer hours of light, they won’t be as vigorous or as long-lived. Be aware that exposure to direct sunlight can burn bracts and leaves.
Soil
While poinsettias are typically purchased already potted from a garden center or nursery, if you’re planting (or replanting) a poinsettia, choose a well-draining peat-based potting soil for best success. In warm climates (zones 9 to 11), poinsettias can be planted into the landscape, where they thrive best in a well-drained, acidic to neutral soil.
Water
Water your poinsettia whenever the soil surface feels dry to the touch. Saturate the soil completely until water runs through the drainage holes in the bottom of the pot, but do not let the plant sit in water. If the pot was wrapped in decorative foil, be sure to poke a few holes through the bottom to allow excess water to drain away. Overwatering is the quickest way to kill a poinsettia, and wilting leaves and rotted plant roots are usually signs of overwatering.
Temperature and Humidity
To keep your poinsettia in bloom as long as possible, maintain a temperature of 65 to 75 degrees Fahrenheit during the day. A slight drop in temperature at night will not hurt the plant. However, cold drafts, allowing the leaves to touch a cold window, or more importantly, a lack of adequate light, can injure the leaves and cause premature yellowing and leaf drop. Lack of humidity during dry seasons, particularly during winter, is an ongoing problem for most houseplants, including poinsettias. If your home tends to be dry, consider investing in a small space humidifier to increase humidity levels in the area surrounding your poinsettia.
Fertilizer
Do not fertilize these plants during their blooming period. When keeping the plant throughout the year, you can begin fertilizing in the spring at half-strength when there’s no growth, but not until then. Feed every three to four weeks until the plant is re-established.
How to Get Poinsettias to Rebloom
If you want to grow your poinsettia throughout the year and force reblooming for the next holiday season, you must follow a very specific process throughout the year. Achieving rebloom is not easy, so don’t be disheartened if you don’t succeed on your first try. Follow this schedule for best results:
December to Early Spring
Water your holiday poinsettias, keeping them moist but not soaked. Then, starting in early spring, do the following:
May
In mid-May, do the following:
Summer
Come summer, move your potted poinsettia outdoors. Keep it in a partially shaded location and maintain your watering and fertilizing schedule.
October
Poinsettias are short-day plants, meaning their bud set is affected by the length of daylight. To rebloom, poinsettias need about 10 weeks with 12 to 14 hours of absolute darkness per day. You will have to artificially create these conditions and remain diligent. At the very start of October, do the following:
November and December
About the last week of November, stop the darkness treatment and allow the plant to remain near the window. You should see flower buds at this point. Stop fertilizing around mid-December. Keep watering and treat your plant the way you did when you first brought it home in bloom. If all has gone well, bracts should begin to show color.
Types of Poinsettias
Besides the traditional red bracts, newer hybrids have been bred in a variety of colors, including shades of white, cream, yellow, salmon, purple, burgundy, and pink. Note that some unusual colors, such as blue, are produced using dyes, and if the plant reblooms, bracts will be their natural color. At any given time, there are at least 100 different poinsettia cultivars to choose from. Some recent favorites (along with some long-time standards) include:
‘Christmas Eve’: This is a long-time favorite with pure red flowers, known for its long color season.‘Plum Pudding’: This is the first purple hybrid introduced to the market.‘Alaska White’: As the name suggests, this is a pure white cultivar that blends well with red varieties.‘Jingle Bell Rock’: ‘This variety is a mixture of cream and bright red with glossy dark green leaves.‘Candy Cinammon’: This cultivar has dappled pink foliage, making for a softer appearance.‘Golden Glow’: This soft yellow variety is compact and known to be more heat tolerant than other forms.‘Lemon Drop’: This cheery variety has bright yellow bracts.‘Gold Rush’: This stunning variety combines shades of pink and gold.
Pruning
Poinsettias grown for a single season need little pruning other than pinching off faded leaves. Plants grown for rebloom, or transplanted into the landscape in mild climates, will benefit if they are pinched back frequently during the growing season to produce bushier plants.
Propagating Poinsettias
Most poinsettias are hybrid plants that do not produce genetically reliable seeds, so they are usually propagated by rooting stem cuttings. This is best done by taking cuttings in early summer, as new growth is starting. Here’s how to do it:
Common Pests & Plant Diseases
Like many houseplants, poinsettias are susceptible to a variety of diseases and pests, including fungus gnats, whiteflies, thrips, mealybugs, and powdery mildew. If you notice signs of an infestation or illness, remove the affected area of the plant immediately and treat with an insecticide or fungicide until all signs of problems have disappeared.
Common Problems With Poinsettias
While caring for your poinsettia to encourage it to rebloom, be on the lookout for the signs of leaf and root rot problems described here.
Leaves Turning Yellow
Leaves will turn completely yellow or develop yellowness around the veins of lower leaves if the plant is stressed. There are many reasons for yellowing leaves:
The plant isn’t getting enough magnesium.The plant isn’t getting enough molybdenum (an essential trace mineral) and needs soil pH to adjust to above 5.5.The plant is being over-fertilized.Powdery mildew is starting to form on the leaves and needs fungicide.The potting mix is too acidic.The plant is overwatered, suffering from low light conditions, or low temperatures.
If leaves have small spots with yellow halos, the plant has scab, which requires a fungicide application.
Stems and Leaves Turning Brown
Brown spots form on the plant in various places if it has canker, which might be helped by removing affected portions of the poinsettia. Stems will turn brown or black if the plant has root rot. Remove infected portions of the plant and try to repot the remaining healthier parts in clean soil and clean pots using sterile gardening tools. Apply a fungicide to the plant for protection.
Plant Leaves Falling Off
When a poinsettia defoliates, it doesn’t spell good news and can lead to the death of the plant. It means that the poinsettia has serious canker or severe root rot from being underwatered, overwatered, or overfertilized. If some leaves are falling, the plant might also need a bit more light.
