There are two ways to plant a quantity of bulbs: many in larger holes or singly in smaller holes. I think the choice should be made based on the effect you desire in a given location. At the moment, I tend to like grouping my larger bulbs (tulips, muscari) and plant smaller bulbs singly (crocuses, iris reticulata).
If you decide to plant in larger holes, then I have found it useful to mark the bulb locations with plant stakes. Then stand back and take a look at what you have marked.
|Small plant stakes mark the new bulb locations|
Once you have decided where they will live, it is time to commit and start digging. When planting in the midst of an already full garden bed, maneuvering the excess dirt becomes one of the biggest problems. My favorite way to solve this problem is by using a piece of plastic to hold the dirt.
|Plastic holding the planting dirt|
|Japanese knife made quick work of planting 100 crocuses in the Front Woodland|