I need to move a group of Hyacinths. They are blooming nicely at the moment. When is the ideal time to do so?
Ideally, the time to move a bulb is after they have been allowed their foliage to wither, go brown, to send their starches and sugars back down into the bulb so it can re-appear next spring.
If you dig them before this occurs, the resulting foliage and bloom next spring will be much less robust, probably shorter and the bloom smaller and it wont last as long.
If you must dig them, then plan to pot them up as soon as they out of the ground with some of the soil they are in.
Let them finish doing what they will do until you can replant them back into the ground. If then, you still cant plant them, let them dry for a few days, remove the old foliage and store them in a cool dry place. Three months is about the maximum time to think they can be out of the ground. An old refrigerator is a good place to store them.