December 5, 2025, 4:32 pm | Read time: 3 minutes
Alongside fir greenery, amaryllis, and Christmas cactus, the poinsettia is one of the typical Christmas plants. During the otherwise dreary season, its leaves turn striking shades of red, pink, or white. However, if the normally green leaves also turn yellow, it’s a bad sign. Usually, care mistakes are behind the yellow leaves on the poinsettia.
As a non-native plant, the poinsettia (Euphorbia pulcherrima) requires plenty of care on local windowsills to survive the winter. What many don’t know is that the poinsettia is a perennial plant, not a disposable product. Since cultivating the Christmas plant involves a lot of effort, its purchase is controversial. Those who still choose the plant should avoid the following care mistakes to prevent yellow leaves.
1. Mistake: Not Unpacking
During the Christmas season, it’s peak time for poinsettias. In supermarkets or garden centers, you find the plants in abundance. Often, they are packed tightly together and wrapped in foil. What many don’t know: Poinsettias produce ethylene. This is a ripening gas. Many are familiar with it from various fruits, such as apples, bananas, or avocados. As the name suggests, the gas accelerates the ripening process. In other words, the fruit or plant ages faster. Due to the plant hormone, the fruits become softer and sweeter, or the leaves change color.
The ripening gas usually dissipates into the air. However, if it cannot escape, such as through plastic wrap, the aging process of the plant accelerates. This is noticeable, for example, through yellow leaves. After purchasing a poinsettia, be sure to remove the foil and do not place it next to fruit.
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2. Mistake: Incorrect Watering
The poinsettia naturally grows in the tropical forests of Central America. As a tropical plant, the poinsettia relies on regular watering, but it should be done with care. Too much water can lead to waterlogging in the pot. If the plant’s roots are in overly wet soil, they begin to rot. The technical term for this is root rot.
Plants absorb water and nutrients through their roots to supply the leaves and flowers. An undersupply of leaves leads to discoloration. To prevent this, check the top layers of soil with a finger test before watering to see if they are dry. If not, it’s better to wait before watering. Additionally, ensure proper drainage so excess water can drain away.
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3. Mistake: Too Cold Temperatures
A tropical origin indicates that the poinsettia cannot tolerate low temperatures. If it’s too cold, temperature stress can lead to yellow leaves. Likewise, too warm temperatures can shorten the blooming period, and thus the colorful bracts. Ideal temperatures are between 64 and 68 degrees Fahrenheit. Drafts should be avoided.
For purchasing, this means: Avoid plants that are kept outdoors. The local winter temperatures have likely already caused irreparable damage to the plant.
4. Mistake: Too Little Light
Between November and April, it’s the dry season in Central America. The sky is clear, and there are more sunny days than in the rainy season. In these regions, it’s different. Between November and April, the sun generally shines less, and the days are shorter. However, if the poinsettia receives too little light, the leaves turn yellow.
The plant should receive sufficient light year-round to grow and thrive vigorously. Direct sunlight should be avoided. A plant light lamp can help meet the plant’s light needs during the dark season.