I don't think that is a big problem with mulch on top of the soil. You can always throw a little fertilizer with nitrogen a couple times a year. Or blood meal for example or cottonseed meal and several other hi nitrogen sources. A little bit is all you need.

A great place to ask is the Soil, Compost and Mulch forum here on Garden Web. It's a lively and informative group!

Here is a link that might be useful: Soil, Compost and Mulch forum

There isn't a problem with BARK mulch. The bark has very little cellolose which is the primary factor in nitrogen tie-up. Use it without any fear at all. That's why we can use it as an amendment in our potting mixes and soil.

WOOD chips, even if fresh, don't present much of a problem, as stated by Louisiana, if used as a mulch (top dressing). The larger the pieces, the less likely for problems. If the fresh wood is sawdust sized or mixed into the soil, then nitrogen immobilization is likely to occur.

There's no reason to limit yourself to one material, one time. I add a lot of different materials to beds at various times, whenever it presents itself, like bagged grass from the mower, leaves, "old dirt" from repotting potted plants, got a load of trimmings from the shrubs around the bank across the street once, DH's Mom wants pine needles raked occasionally, so over here they come, a few bags of peanut shells here'n'there... Anything that doesn't need to be composted first, it's easier to just spread it around, IMO.

Whenever I've bought mulch to be used AS mulch, it's always been shredded hardwood. I've read material warning about tanic acid from large quantities of oak leaves, but not shredded hardwood mulch. I like the way it breaks down quickly, moderates moisture excellently, the dark color, and inexpensive price.

We live close, jacksonville nc, and use hardwood mulch and found it breaks down great. I use my old mulch mixed in with topsoil for the next years growth when I renew my mulch. I love hardwood. I found pinestraw way cheaper than mulch though but I hate pinestraw.

my hostas LOVE the hardwood mulch, mine is the shredded type.

my house is surrounded by oak trees and pine trees and both have caused nothing but problems for me as oen corner of my yard fills with them both and must have ffor years before we lived here because nothing not even grass will grow there and my soil tests for that area were horrible.