William Brown wrote:
I would suggest you wait until next year. This will give you a chance
to see what is already there, and to note any problems. Once you know
what you have, then you can decide what to keep. I have one tree, for
example, that is mediocre in the spring and summer, but is beautiful in
the fall; the only way to find out what you have is to give it a chance
to bloom.

I strongly third that advice. I was in your situation last year: first
time homeowner, first-time taking care of a yard, plus new to the area
and not knowing the plants. I didn't even mow for a while, because I
wanted to see what was there. Turns out there were rose and crape myrtle
bushes that had been mowed over by the previous owner's drunken
crackhead lawn guy, and needed time to recover and be beautiful again.
Plus, an entire hedge of nandina that had either gotten the same
treatment or sprouted up from the neighbor's seeds. I was ready to fill
in a hole in the front yard, and it sprouted canna. If I'd been too
quick to slash and burn, I'd be out at the garden center now purchasing
these plants which I would have never known that I'd had.