By Bernard
Cambridgeshire,
United Kingdom 
Is there a rule of thumb about the depth to which bulbs should be planted?
12 Oct, 2010
Answers
There are some exceptions, though, such as Bearded Iris, or some species Tulips. Don't sweat it though--over time, bulbs usually just adjust their depth to fit the growing conditions, though it may mean an extra year or two without flowers.
13 Oct, 2010
I go three times the size of the bulb.
12 Oct, 2010