Now is the time to think about lifting and dividing those overcrowded clumps of snowdrops as it is always best to do so as the foliage is just starting to die back. If you can, remove any spent flowers or seed pods to give the bulbs the best chance of developing and flowering the following year.
Use a fork and dig deep underneath the clump so you don’t damage any bulbs or the roots; the roots are an important part of the snowdrop and too much damage here can result in poor flowering. Don’t let the bulbs dry and plant the snowdrops back (around 15 cm deep) as soon as you can. They love humus rich soil.
Give them dappled shade and moist well drained conditions and their beautiful pure white bells will reward you for years to come.