These days, it is a lot easier than it used to be to make ecologically responsible choices by growing native plants that are not wild collected. I know of no better place to do this than New England Wild Flower Society. There are two locations, one at Garden in the Woods and the other in the western part of the state. The one at Garden in the Woods has the added bonus of being able to see mature specimens of the plants at the botanic garden, that also has excellent exhibits. They are about to launch a show by a great landscape architect-Gary Smith-and if you've never seen his work before, you're in for a treat. I was at the nursery today and picked up some fabulous shooting stars-and a sourwood that I had been coveting for a long time. I'm going to return for the big opening of the show in a couple of weeks, so I became a member of the organization which allows me to visit the gardens for free. I like that what I spend goes to support conservation.
Excellent source for hard to find natives. You can buy with confidence, knowing they are ethically harvested. My shipment came very promptly. Their on-line catalog has detailed germination requirements. I ordered hard to germinate stuff - so can't comment on seed viability.
They are well know in their area as being the best at what they do. With 35 years in landscape composition and hosting a radio show on that topic (including interviewing them) I am in a position to know of what I speak.