Answer: It may be natural for your myrtles to lose their leaves this time of year, even though they're growing indoors. Here are some general pointers for topiary care: During the winter, most plants used as topiary will appreciate a cool, bright location with ample humidity. The soil should be kept moist but not sopping wet, and fertilizing should be reduced or stopped during the winter months. The plant will naturally slow its growth for the winter and pick up again in the spring. When this happens, fertilize more often according to the label instructions and increase the watering proportionately. When the plant is in active growth you will need to trim it back lightly but frequently to maintain the topiary shape.
A complete link to larger shrub topiary is found at http://www.geocities.com/RainForest/Vines/8433/links.html
Best of luck with your topiaries!
Q&A Library Searching Tips