Purchased trees, wait till fall to plant, or get in ground ASAP?

Purchased trees, wait till fall to plant, or get in ground ASAP?

Hi, friends. I perused the topics, but didn't see an answer to this specific question. The local nursery recently had a huge 50% off sale and I bought a flowering plum tree, a red-twig dogwood shrub, and several firethorns at a great deal. I know this isn't an ideal time of year to plant, so I was wondering if it's better to keep them in their pots, in a cooler area of the yard, and well watered and wait till the fall, or if it's better to get them into the ground as soon as possible, maybe planting them in the evening on a cooler day? (I'm in Boise Idaho, zone 6a and our weather has been in the 80's-90's and looks to be staying that way in the near future). Thanks, everyone!
My first seedlings!

My first seedlings!

Future Domestic

Future Domestic

A little of my garden

A little of my garden

Painting my walls.

Painting my walls.

Hello!

Hello!

Bored at work…so I’m posting pictures!

Bored at work…so I’m posting pictures!