Lifting & moving
Before we discuss when and how to move snowdrops we can learn a few crucial pointers from their structure and their growth in the wild.
Snowdrop roots
Snowdrop roots grow from the base of the bulb and are renewed annually. However, like many members of the Amaryllidaceae, snowdrops do not usually shed their roots at the same time as the leaves and flowers die off. Many snowdrops keep their old roots throughout much of the summer and only lose them shortly before the plant starts into new growth in the Autumn. The reasons for this are not clear. The roots may still be active, taking up small quantities of water and nutrients; or they may have a sensory function, telling the bulb about the temperature and humidity of the surrounding soil. The loss of these old roots seems to upset the plants. If the roots are lost by being broken off when the bulbs are moved, their growth next year is often delayed. If the roots are lost through drying out of a bulb exposed to air for long periods, the result is usually fatal.
Snowdrop roots, like many bulbs, are long thin and unbranched with a growing point at the tip. If this growing point is damaged, further growth of that root is prevented; the damaged root will not branch. If all the roots are damaged in this way, particularly early in the growing cycle, the results can be very serious. A bulb that has been damaged in this way will be small, soft and underweight when the leaves die back. Such a bulb will take one or more growing seasons to recover to its pre damaged state and some will just dwindle further.
It is clear from the above that the primary requirement is therefore to avoid physical or dessication damage to the roots; irrespective of the season.
Summer baking
Snowdrops may come from countries significantly warmer than our own, but they are not adapted to withstanding drying out of the dormant bulb; unlike most tulips and many crocuses. If they are left out of the ground and exposed to the air for even short periods, they are likely to be damaged; which will manifest as poor growth in the following season.
Lifting and moving when dormant
The best time to lift and move snowdrops is when they are dormant; i.e. after top growth has died back and before new root growth has begun - between June and late September for us. Lifted bulbs can be easily stored during this period in a shady cool corner and covered with a few centimeters of compost. They will be unharmed until ready for planting, dispatch or giving away; and can stay this way for weeks if necessary.
Lifting and moving "in the green"
Many commercial nurseries lift and despatch snowdrops in early spring when they are in full growth - so called "in the green". This has become more prevalent and has acquired a certain mystique as if it is an essential technique with snowdrops; it is not.
Moving in the green has several advantages for the seller. The bulbs are easily found and lifted from the ground. It is easy to confirm true identity and it is easy to sort out flowering size bulbs only.
However, it must be done without damage to the roots and their tips and the lifted plants should be replanted or posted right away. Plants received in the green should be planted as soon as they are received and every effort made to ensure the roots are undamaged and yet firmly in contact with the new soil.
Our experience is that in the green is not ideal. Almost all bulbs received postally in the green take a further year to settle before growing strongly and flowering.