Freezing dill will allow you to keep it usable for months down the line. You can freeze the leafy stems and flower heads. Start by rinsing the dill fronds and flower heads with water, which will remove any remaining insects and dust. Gently shake them after to reduce the amount of residual moisture.  Hang the bunches upside down to dry, which will help them keep their shape. If you don't want to hang your dill upside down, put it on something absorbent, such as layers of paper towels. You don't want to let it get too dry, though. When ready, put your dill in an airtight container. If you can set the container upright in the freezer, your dill will retain its shape.