Plant in groups of three or more for a clump effect. The rule of thumb for all bulbs is to plant at a depth three times the widest diameter of the bulb. Some summer bulbs, however, should be planted deeper. For dahlias, for instance, dig a hole 1 foot deep and several feet wide for each tuberous root. Add several inches of loose soil to each hole, then plant tuber. Cover tuber with 3 inches of soil; water. As shoots emerge and grow, gradually fill hole with soil. Plant all bulbs pointed side up, root side down; when in doubt, plant sideways.
Bulbs contain most of their own food supply, but for best performance:
1. Add a high-phosphorus bulb food to the bottom of the hole when planting, to encourage root production.
2. Feed with an all-purpose fertilizer when the plants start to grow.
3. Feed again after flowering to help bulbs store up energy, if you are going to replant them next year.
After leaves have died back, bulbs can be prepared for winter storage, if necessary. (In frost-free areas, these bulbs can overwinter in the ground.) Dig up, or knock them out of their containers. Remove dried leaves and soil. Spread the bulbs on newspaper and let them dry in a shady spot for a few days. Bulbs that have their own protective tunics, such as glads and crocosmias, can be stored in baskets, boxes, or mesh bags. Store the rest between layers of vermiculite, sand, or peat moss. Store all summer bulbs where they will be protected from cold, heat, and moisture.