A: Fall color questions are one of those types of questions where there probably isn’t one single reason, but several factors which can contribute to how well a particular plant colors up. Much like questions of a wisteria’s bloom, anyone who comes up with the perfect answer to this question will be a wealthy person at some point in the future.
Here are a few likely reasons for the color difference in those two Chinese Pistache trees:
- Irrigation differences. The moisture a plant receives will influence how well the color turns and how long the color holds; plants which are too wet or too dry for the species might not color as well as a plant in ideal conditions. Humidity differences and how much stress a particular tree took in the summertime also plays a part.
- Sunshine. Other trees planted too near your Chinese Pistache can partially shade the tree, which does not promote the best fall color.
- Male or female? Female Chinese Pistache put out a pretty, small red seed in the fall but don’t generally turn as red as a male Chinese Pistache. It’s difficult to tell a male from a female when the tree is a young sapling.
- Tree maturity. Well-established trees generally show better color than younger or newly planted trees.