Tulip varieties bloom at different times during the spring season and it is possible to plant varieties of bulbs that will provide blooms from late April through June. The Department of Agriculture does require all imported bulbs pass inspection before shipment. They are pest and disease-free. Do not purchase nicked or scarred bulbs. Bulbs should be firm and plump.
Prebagged bulbs can be a bargain.
But buyers must be wary. A late season sale may offer picked-over varieties. It is important to place the bulbs in the ground as soon as possible so they can develop a root system before winter. Healthy roots mean larger blooms. Planting The size of the bulb determines the depth and spacing.