The lavender flowers of verbena attract butterflies to the garden throughout summer. An annual, verbena varieties range from pretty ornamentals to lemon verbena, which is used as a lightly citrus-tasting herb. While verbena readily self seeds itself each year, to ensure a full bed or to start a new bed more seeds are needed. Saving the seeds from your exiting verbena ensures you will have access to the same variety and saves money over having to buy new seeds each year.
Wait until after the flowers fade and wither away, leaving behind the seed heads. Pick the stalks once the seed heads dry and fade to the same shade of brown as a paper bag.
Place the seed head in a well-ventilated, warm room to dry for two weeks. Lay it in a bowl lined with paper towels to absorb any excess moisture as it dries.
Remove the paper towels, then crumble the seed head into the bowl. Remove any large pieces of non-seed plant matter.
Label an envelope with the verbena variety and the year the seed is harvest. Place seeds into the envelope and store in a cool, dry place.
Alternately, fill a cloth bag with 1/2 cup powdered milk and place in the bottom of a jar. Place the seed envelope into the jar and screw the lid on--the milk absorbs any excess moisture. Store in the refrigerator until ready to plant.