>identified because they have that "crown" like blueberries

I think they mean that the fruit has a crown at it blossom end, similar to blueberries. I don't think it's refering to the plant. In the East, Service berries are vulnerable to Cedar Rust (Weather it's Cedar Apple Rust (CAR), or Cedar Quince Rust, I don't know). They are actually related to Pome fruit (Apples/Pears) and have an almond taste.

I think even biologists have trouble differentiating the species of Juneberries/Serviceberries (which are the same thing - unless you were looking to have Sorbus (which also known as Serviceberries or Rowan).

From the Wikipedia entry, the nursery trade is using the various species names interchangeably and don't always know what they're offering.

Here is a link that might be useful: Wikipedia Serviceberry entry