This often happens to summer planted lilies. The earlier you plant them the better. you can plant when soil is frozen if you like (if you do not water too much).

The best conditions for planting lilies are when night temperatures are 40F and daytime above 60F this gives good root growth. therefore planting in march or april is better than july.

good news is that the bulbs will usually come back the next year.

Probably not what you wanted to hear... ??

-- Kenneth