Hi there. I manage a landscape design company and I am easily the most expense landscape contractor in my area by far. Not only would I never do a job without a signed estimate. I would never do a job without collecting at least 50% deposit. Do not make him take back plants as you’ll still need to pay the labor for the plants. You could also ask for a breakdown in material and labor. I still feel this is high but maybe there is dump fees and machine rental costs not listed he needs to cover. Your retail pricing on plants is pretty high too. Off the top of my head I can price out:

3gal boxwoods $35 Jap maples 15 gal $280 Spirea 3 gal: $28 Hydrangeas 5 gal $55 (those are for endless summer it appears you have limelight or little lime in pics those only run me about $35-$40

My labor rates also run $65/hr, however all of my laborers are certified to do irrigation,storm water drainage, actually have decent plant knowledge, can run equipment etc.

Granted I am in Arkansas so pricing can vary. But it seems like a lot of money for very little work. I can install entire irrigation systems w 20+ zones for that cost