Lemon verbena is a must have plant. Leaves are wonderfully lemony scented, with a tart lemon flavor. It is great for teas, desserts, really all kinds of cooking where lemon juice or zest is called for. This plant is native to Peru, Chile and Argentina. It is only hardy to USDA Zone 8, but absolutely worth the effort to overwinter it. In milder climates it can easily grow in the ground. Lemon verbena can grow to 6 feet or more. Small terminal white flowers attract beneficials, but many gardeners find they are so busy pinching this plant to make tea, ice cream, pot pourri, herbal steams, stuffing into chicken, putting into bouqets, adding to vodka, chopping into muffins, layering into sugar....well, you get the idea, you can find endless uses for this plant. It is a useful medicinal plant as well. Pinching is also useful because the plant is naturally rangy, so pinching will help develop side branching.
Lemon verbena is deciduous during winter, so don't make the assumption it is dead when it drops all of its leaves! Prune it back to about knee high, at a node. Wait until mid April before starting to worry about the plant being dead - it is always late to leaf out. Lemon verbena prefers full sun, although it will adapt fine to afternoon shade. If your winters are marginal, plant near the house or fence, or grow as a container plant. Average garden watering is fine, although we find that deep watering once a week is more than enough, even during the hottest part of the summer.