Locating planted bulbs

[SouthernGardening]

Does anyone have suggstions for locating established bulbs in a mixed planting bed? One of my clients has perennials, annuals and bulbs all planted in the same general area under some oak trees. I hate digging up bulbs already in the ground when I'm planting annuals or adding more bulbs . Or worse, unearthing half a bulb.

[Atlantic Lawn]

I have always gone low tech, small sticks that are just barely above the mulch level marks my bulbs.I know this isn't much help now.Sonicgram would be very cool.

[SouthernGardening]

Thanks, Steve. Good idea for future plantings. And unearthed bulbs come spring.