Sweet fennel is the type usually used for tea and has a strong licorice flavor when dried. To use fennel for tea wait till the plant goes to seed at the end of the summer, or in early fall. The seeds can be left right on the plan to dry if weather permits, otherwise you can collect the seed and allow to dry completely in an airy and shady location. Fennel can be large, up to six feet all. Consequently it isn’t the best choice for a house plant for most people homes. Refrain from planting close to dill. They are related and can cross-pollinate. Fennel grows best with plenty of sun and water.