Those were ID'd as Weigela florida - note the opposite arrangement of foliage. Very different from any Spiraea sp. that you'll ever run across.
The little tree is a Sweetgum seedling Liquidambar styraciflua, NOT a Maple. Again - note the arrangement of foliage. The leaves occur alternately along the stem, rather than opposite as in all things Acer...
Again - you can post pictures of dormant plants from which contributors here can help confirm the identity of your plant. You can even prune off a stem, bring it indoors on a countertop, and take some closeup images that way.
There are a number of dwarf selections of Weigela florida which have the dense congested stems as you've described. I've got one that I planted ten years ago that is not more than two feet tall - Wiegela florida 'Minuet'.