Poinsettia plants remain one of the most popular holiday flowers.
The familiar red flowers have been joined by even flashier colors to include pastel yellow and vibrant bi-colors. Because poinsettias have been forced into bloom, they need some extra care to keep them healthy and looking good throughout the holidays.
Here are some questions related to watering, with answers from horticulturists at Iowa State University. To have additional questions answered, contact the ISU Hortline at 515-83-3108 or email@example.com.
Q: Why is my poinsettia dropping some of its leaves?
A: Improper watering is the most common reason. Over-watering will cause the lower leaves to turn yellow and drop. Under-watering, or allowing the plants to get too dry, also will cause wilt and leaf-drop.
The water needs of a poinsettia can be determined with your finger. Check the potting soil daily. When the soil surface becomes dry to the touch, water the plant until water begins to flow out the bottom of the pot.
The pots of most poinsettias are set inside decorative pot covers. When watering these plants, carefully remove the poinsettia from the pot covering, water the plant in the sink, then drop the poinsettia back into its pot cover.
Also, make sure the poinsettia is not located near a heat source or cold draft. Warm, dry air blowing across the plant from a furnace register or rapid temperature fluctuations (such as near a door) can also cause leaf drop.
A: My poinsettia suddenly wilted and died. Why?
Q: The sudden death of the poinsettia is likely due to a root rot. Pythium and Rhizoctonia root rots typically occur when plants are watered too frequently and the potting soil is kept saturated.
Allow the surface of the potting soil to dry to the touch before watering poinsettias. Also, don’t allow the pots of poinsettias to sit in water. Discard excess water that drains into pot coverings or saucers.
Q: Small, white insects flutter about my poinsettia when I water the plant. What are they and how do I control them?
A: The small, white insects are likely whiteflies, a common pest of poinsettia, hibiscus, chrysanthemum and a number of other indoor plants. They are most often noticed when watering or handling a plant. When disturbed, they flutter about the plant for a short time before returning to the plant.
Heavy infestations may cause stunting or yellowing of leaves, leaf drop and a decline in plant health. Whiteflies also are extremely difficult to control. It’s often best to tolerate the presence of a small infestation and then promptly discard the plant after the holidays.