Q: Do you have any information on how to preserve water lettuce from year to year? I started my pond with just three plants and they have multiplied beyond belief.

A: Water lettuce is an attractive pond plant but it is very sensitive to cold water. The best way to keep it over winter is to float a few plants in an aquarium equipped with a water heater. Plants need lots of light so put the aquarium right next to the glass of a south-facing window and consider adding above it a domed shop light with a 100 watt equivalent CFL bulb. But that’s a lot of work to preserve a plant that reproduces so quickly. My honest advice is to buy new plants each spring.