Nice idea, these items will surely add some nice eyecandy to certain levels. But most people whoare aware of styles won't use this in SMB3 levels, as nothing here is actually SMB3 styled, like you claim it is (I presume since you have the SMB3 in the title).
Your shading is rather inconsistent: The wooden items look round (on the z-plane which isn't shown in 2D graphics) due to their diagonal shading (which isn't necessarily bad but I'm not used to
convex wood), the bush doesn't really have any noticable shading, the flower stems receive their light from the floor and the petals are pillowshaded.
Here are some suggestions which, in my opinion, could make this set more viable:

My shading on the bush is too strong, but you get the idea.