WOOSTER, Ohio — Poinsettias are America’s favorite Christmas ornamental plant. Whether you prefer traditional red, white, pink or any of the marbled and speckled varieties now available, you want to make sure you select the right poinsettia and take the proper care so it can thrive during the holidays and beyond.
“When you go to the store, inspect the plants carefully and make sure that you don’t see leaves that are dried out, that are sagging, that have obvious signs of damage,” said Luis Cañas, an entomologist and expert on greenhouse ornamentals with Ohio State University’s College of Food, Agricultural, and Environmental Sciences.
“Then approach the plant, gently turn the leaves and take a look at the underside of the leaves, which is where a lot of the insects live. It will very obvious to you if there are signs of insect presence there.”
One of the most common insects found on poinsettias are called white flies. If present, they will be on the underside of the leaves. White flies are very tiny, pure white, and scaly in appearance.
“The quality of the plants found in Ohio is really good and rarely you find these insects, but it’s always good to check,” said Cañas, who works with Ohio’s large greenhouse industry to find economical and environmentally friendly ways to get rid of white flies and other pests of ornamental plants.
In addition to the leaves, it is also important to check the plant’s roots, Cañas said.
“Grab the plant and gently tap on the pot so you can turn it upside down and check the roots,” he said. “The roots need to be of a whitish color; that’s a sign that they are healthy. If they look too brownish or even blackish, and when you touch them they peel off, that’s a sign that the root system is not very healthy. Even though these plants will last between two and three weeks, they may end up dying because of this problem.”
Cañas also recommends you pay attention to poinsettias that are not watered properly at the garden store and avoid buying them.
Poinsettias are native to Mexico and Central America and don’t like cold weather. When you take your plants home, avoid placing them too close to windows or places where they will be exposed to a cold breeze. Additionally, keep them away from heater vents to avoid drying the leaves.
“Poinsettias will do well where there’s a lot of sunshine,” Cañas said. “Be careful with watering. One of the biggest problems taking care of plants is overwatering. My recommendation is to let the soilless media dry before irrigating again.”
Cañas said poinsettias usually come well fertilized from the greenhouse, but if you want to keep them longer, it’s a good idea to use a slow-release fertilizer to keep them healthy and strong.
“If you ever see insects on the leaves, it’s easy to manage them using insecticidal soap,” Cañas said. “It usually comes as a prepared fix. Gently and thoroughly spray the leaves so the insects will die. This type of product can be used inside the house.”
You can enjoy the beauty of poinsettias well after the holidays with the right amount of care.
“Poinsettias can be kept all year round. A lot of people are surprised to hear that,” Cañas said. “If they are watered and fertilized properly, they can grow for a long time. In fact, they can grow into large trees.”
As they grow, poinsettias will need to be repotted into a larger pot. Also, to make them turn color, they need many hours of darkness.
“That’s difficult to achieve at home, but it can be done,” Cañas said. “In August or September, put them in the basement or another dark place. They will need 14-16 hours of darkness a day until they turn color.”
More details about poinsettia care can be found in an Ohio State University fact sheet, “Poinsettia Care in the Home,” at go.osu.edu/uqg.