How about a tree/shrub that hosts the butterfly larvae, like spicebush which hosts the spicebush swallowtail? You didn’t provide your location, but it may be native in your range. It may need to be pruned back as it grows to stick to your size requirements.

Location is RI

It sounds like you might prefer a shrub rather than something that dies back completely to the ground every year, correct? I have abelia on the east side of my house that attracts swallowtails. It blooms a long time for a shrub. I wish I could remember what kind of abelia it is. Sorry. I'm in zone six and if we have a cold winter, the top of it will die back part way. Last winter we had a night that got down to around 15 below so it only grew to around three feet tall but normally is more like 5 feet tall.

Christie this seems like a good fit. The area only gets morning sun, and I was looking for more of a Woody plant similar to a butterfly bush that will attract butterflies.

Clethra ruby spice I think would do great for you. it has a very strong perfume smell and literal clouds of pollinators when in bloom.

New Jersey tea (ceanothus americanus) would be a good choice for you. It's also native to your area I believe. Also, I noticed you didn't mention what type of soil you have (clay, sandy, etc). That should also be considered when choosing plants for an area.