You can plant lilacs any time.......the earlier the better for them (and most plants) as this gives them a chance to grow and spread roots before the summer heat and drought. You could technically plant in summer.......but for some time the roots would be in the little area of the original pot......and this would dry out far faster/easier than the surrounding soil could replenish. Right now the days are cool, rain is (usually) more frequent (though you still need to water periodically), the plants have less leaves (= less water evaporating from the plant). I would definitely buy POTTED lilacs now. Bareroot plants only when completely dormant (e.g. winter).

Where in the state are you? Butterfly bushes can be invasive in some areas.....usually moreso in the south and Pacific Northwest, less so north. Here in central NJ I have not found them to be a problem. I used to get the occasional seedling but hardly often. One or two recent cold winters actually killed off my butterfly bushes and some in the neighborhood that had thick trunks too. I remember staying at a hotel near Ocean City years ago with some butterfly bush seedling in an abandoned lot next store (actually kind of neat!). By the way there are some smaller size hybrids out now and/or even sterile or near sterile hybrids so you don't have to worry about seedlings at all. BTW the butterfly bushes and lilacs have a very different growth and bloom pattern. Maybe that is what you want and that is fine.

Sounds like you have good soil. As long as the deer are not bad in your yard that gives you a TON of options for shade and sun. A lot of awesome Hostas and Heucheras for shade....add some bleeding hearts for the Spring, maybe Hellebores for winter/early interest. Sun you have even more possibilities. Get things that bloom all times of the year. Enjooy!

Woodnative I’m in southern Jersey shore just passed T.R.

Ty for all the advice much appreciated.

what types of lilacs do u have that grow great or ones that had large hype but didn’t work out well? Any suggested B.B.’s?

I wanted the alternating lilac, butterfly bush to give different heights, thickness & have blooms at more than one time. Love landscapes & gardens that have something beautiful going on as many seasons as the crazy weather here allows.

No deer to worry about, away from the more woodsy areas & all yards including mine have 6-8’ (some even 12’) foot fencing. Ours is a menagerie of heights due to property lines & exsisting fences we don’t own. We have inground sprinklers in the area where the lilacs & butterfly bushes would go so plenty of water but still nice drainage.

Just to add, alternating plants never looks good. Much better look is grouping them. And yes, Buddleia are invasive. Invasive means that they escape into the wild, not that they are all over your yard. A plant that wants to take over your yard is referred to as agressive.