Whoever told you that didn't know what they were talking about. I have all kinds of flowers and bulbs near my many bamboo and never noticed a problem. In fact, for aesthetic reasons I have had to weed out flowers when they were crowding around the bamboo clumps, so I think that tells you something.

Generally as rhizomes spread they are 4"-10" below the surface, so they simply go under the flower root system. I've never had a situation where a bamboo rhizome interferes in any way with flower growth. Unless you are planting flowers that need full sun and they are heavily shaded by masses of bamboo leaves you should be fine.

I do rhizome prune to control the spread of my bamboo and occasionally they grow through the root system of large grasses, so that makes removal of pruned rhizomes a little more work, but it doesn't hurt the growth of the other plant even when the roots are commingled. In short, the bamboo doesn't compete with the flowers or put out some mysterious deadly compound. Plant your daffodils and show your friend your lovely garden next year!

Thank you Kudzu!! I couldn't imagine the rhizomes being so obstructive as to strangle the little bulbs but, what do I know? I have about 100 bulbs I'd like to put in the planter around the base of the boo.

If you have your bamboo in a small-ish planter, at some point it may start to get crowded in there with rhizomes, and this might make it hard to dig down deep enough to plant bulbs. If the planter is pretty big, I don't think it would be an issue for a long time.

It's over five feet wide and about 20 feet long.

Then I think you're good for a long time...