Hi Fagopher:

Tree 6 is a weedy mulberry (Morus alba). They are difficult to get rid of because they keep sprouting from the stump if you cut them down.

Plant 7 is a spurge (Euphorbia). Not sure if it is native or exotic.

Plant 6 is another tree weed, tree of heaven (Ailanthus altissima).

Plant 1 is Lily of the Valley (Convallaria).

Plant 5 is a Peony.

Plant 4 is a dwarf Spirea that will have pink flowers soon.

Plant 8 looks like a lilac but I'm not sure.

Plant 9 looks like a gooseberry (Ribes).

Thanks for the info. That is a great start!!

Hi!
2. This might be a perennial geranium. They have purple flowers.
3. yes, allium, ornamental garlic of some kind.
7. This looks like Siberian Wallflower. Are the flowers orange and frangrant? If you like it, that's great. If you don't pull them out before their slightly swelling spine-like leaves swell and pop open with seeds. The seeds will go everywhere. It's a biennial. It looks a lot like dianthus in the beginning (at least to me).
Heidi in Nebraska

Tree 1 looks like Burning Bush, identifiable by it's unique stems. Bright red foliage in fall.
Tree 2 looks like Redbud, identfiable by it's heart-shaped leaves. Blooms in early May.
Tree 3 appears to be lilac, blooms in May
Tree 7 - maybe an ornamental cherry of some sort. The shiny bark with white lenticels are an identifier.
Plant 7 is spurge a.k.a. euphorbia
Plant 1 Lily of the Valley
Plant 5 Peony
Plant 2 is not geranium, but hard to from photo. Has it bloomed yet? That would be a good identifier.
Plant 11 Is it spiny? If so, could be barberry.