Later blooming cultivars may be less affected by late freezes but their flowers may not last as long if hot spells hit in late spring. But, be sure to plant approximately six weeks before the ground freezes to allow sufficient time for rooting. Bulbs will root best in cool soil and once rooted undergo natural changes that keep them from freezing. Water your bulbs after planting to help them start the rooting process. Do not put the fertilizer in the hole with the bulb as this may burn the bulb's tender roots.
Deer can be major problem with edible tulips and lilies.
Cornell University trials of products such as Deer Off , which must be applied at emergence and until bloom, have had some success.