if it were me...

i would get a bag of professional potting medium ... a peat perlite mix... and a bag of mini bark chunks .... and mix them together ... wet it.. then plant the trees in pots ... and then put them in very bright shade, but not sun ... when you water them.. you want the water to drain out the bottom almost as fast as you put it in ...

and then plant them in the fall after the other trees lose their leaves ...

then go dig your holes ... and redig them every few weeks until then .... so that the soil is well broken up by fall ...put a nice blanket of mulch over the holes .... and it should be great planting in October ...

i would add no amendments to the hole ...

after you dig the hole ... pour 5 gals of water in ... and see if it drains from the hole ... most pines HATE wet feet .. and like the sand they were growing in ... if you soil is so clayish that water pools for an extended time .. you will need to do a new post on how to plant them above ground ... on a mound ...

or just stick them in the ground.. mulch them .. and water them properly .. and dont give it another thought.. lol ..

good luck .. ken

I also have thick clay soil. When ever I have a bare root tree in the heat of the summer I plant them in a pot of good draining potting soil (I use Miracle-Gro potting mix) keep the soil very moist for several days to reduce shock (because they will go from water to soil) then you can ease off of watering when they start growing water feeding roots in a few to several days in the soil. and keep them in the pots until they start to show a little growth on the twigs. When you see a tiny bit of growth then plant them out in the ground. Don't leave them in a pot for long because they will become root bound which is not good for the tree. You can plant a potted tree any time of the year as long as the ground is not frozen. I think in a pot for a few weeks would be good then plant them, defiantly before fall comes so they can grow some roots in the ground before the winter cold and freezes. When you plant the trees out, dig or till a large wide hole 3 to 5 times as wide as the pot (but not deep, just deep enough for the root ball, this will help the roots to spread easily and establish) and plant the top of root ball about 1 inch above the ground so the root ball will not drown in the slow draining clay. Don't add soil amendments the tree will adjust fine from the root ball to the clay soil and also don't pound the soil around the root ball when filling the hole back in just lightly press the soil down with your hands around the tree while watering and adding the soil back. Then finally mulch the area with 2 to 4 inch layer of organic mulch to insulate the roots, retain moisture and to also give the soil nutrients. Keep the mulch off the trunk.

Recommend you plant them in soil or pot as mentioned above immediately. Too much time in a bucket of water can be a killer for a lot of conifers. "Well-drained" is a key word with most conifers and sitting for days in a bucket of water does not meet that definition.

I have planted some pines,they are about 1 to 2 feet tall. I was told to use fertilizer and then read not use it at all for 2 years so that the roots grow more than the top.
What is the best some are blue spruce and others are a very short needle pine.
Thank you