A series by Eugene Howell
In the art of bonsai, it’s easy to get caught up in the mystique of the art and lose sight of the fact that our medium is a living plant. While having a beautifully developed bonsai is the artistic goal of the art form, it sure helps if the tree is still alive when we reach that goal.
As with all plants, whether in a pot, in the ground, or in the house, there are four fundamental environmental-factors which determine whether a plant grows in a robust healthy manner, or whether it withers and dies. These are light, temperature, water, and soil. When one or another of these goes out of whack a bonsai tree can begin to suffer and show symptoms of ill health. If not corrected, the tree can languish or die, so it’s important to thoroughly understand the role that each of these plays in the health of your tree and to keep them within the acceptable bounds for the particular species you’re working with.
There are two more factors that can play pivotal roles as well, but these are considered secondary to the four fundamentals mentioned above. They are pests and disease.
In this series I’ll be discussing bonsai care in detail, but today let’s take a look at just one part – temperature.
Every plant has a temperature zone within which it is genetically programmed to grow well. The North American continent is divided into 11 hardiness zones, with the coldest ones being labeled with low numbers and the warmest ones labeled with higher numbers. Zone 3 is the coldest within the lower 48 states. This takes in parts of Montana, North Dakota, Minnesota and Wisconsin. Zones 9 through 11 are the warmest and cover the majority of the Florida peninsula. In Brevard County Florida, I’m in Zone 9, with the southern part of the county being in Zone 9b and the upper, western part of the county being in Zone 9a.
If you attempt to grow a bonsai that’s not meant for your hardiness zone, it may survive if pampered well, but it probably won’t flourish. This particularly holds true if you’re in a warmer zone trying to keep plants that normally grow in cooler zones. Some of these are Maples and several types of Juniper, among others.
Tropicals, however, are plants that normally grow in zones 11 through 12 and will do very well in zones 9 through 11 if given adequate bonsai care and cold weather protection. Many of these tropicals will tolerate temperatures down into the 50’s but will begin to suffer when exposed to the 40’s. They will usually die if exposed for only a few hours to temperatures in the 30’s. Some of these are Bouganvillea glabra, Myrciaria cauliflora (Jaboticaba), Neea buxifolia, Ficus (var.), Carmona microphylla (Fukien tea), and Conocarpus erectus (Buttonwood).
Make sure that you know the temperature requirements of the trees you want to bonsai. Avoid having your beautiful bonsai damaged or killed because you failed to research its temperature needs.
Photo credit – Acer Bonsai En Primavera by Manuel Martin Vicente