Three inches of mulch is okay for most bulbs to grow through, it would be helpful to know what kind of bulbs you have growing and what material you are using as mulch. If the mulch is a coarse heavy texture the plants will have a more difficult time getting through to the surface.

In my garden chopped up tree leaves from my lawn mower piled up 8 - 10" in spots and the daffodils are sprouting and growing through it without any problem. One of these days I need to get out and distribute my mulch a little more evenly!

Your bulbs will grow without any problems if you keep mulch as is, or remove some of it - if it were me I would just keep an eye on your bulb sprouts and if any are struggling take some mulch off of them. My educated guess would be to just leave them alone, they will be alright!

Hi and thanks for the response.

We have Delphiniums, Double Hollyhocks, Dwarf Lupines and some other various bulbs in these beds.

I'll just keep an eye on things.

Thanks again.

HU, none of the plants you name are bulbs. They're all hardy perennials and they'll all come up through mulch.

For future reference don't tag 'Ask the Yard Doctor'. A bizarre quirk of Houzz means that nobody entering this topic via Gardenweb can comment if you do that. So you don't get replies from people who are most likely to be knowledgeable and helpful. I had to reenter via Houzz and pretend to be in the USA in order to answer your post.