Question about planting bulbs?

I plant my tulips and daffodils in clumps spaced throughout my beds. I dig a hole and put in 5 bulbs in a circle with 1 in the middle. I space them about 3 inches apart. Tulips come in early medium and late varieties. I mostly use the early varieties. When they are finished blooming I remove the dead flowers and let the foliage die back to feed the bulbs. I pick one spreading annual --usually petunias and I plant 3 or 4 of them around--not on top --of where my bulbs are planted. I cut off the dead bulb foliage when it's brown and the petunias spread over where the bulbs are and you never know they are there in the summer. The bonus is that if you have to dig up the bulbs in the fall for some reason you know exact;ly where they are.