All bare root trees, raspberry, blueberry plants should be started indoors. These are dormant plants and will not have leaves. No leaves no sun needed. The sun will dry out the stock and kill the plant. So plant them indoors ( unless you have a spot that never sees sun, a spot that is much cooler than the sunny part of your yard) for the first two weeks or until you see leaves develop. It has to have growth before you decide to transer.. The plant cannot protect itself or use the sun without leaves. Slowly acclimate the plant to the sun and not take it from 70 degrees to full sun in one day. It is hard on the plant and will struggle to survive. The plant is trying to establish a new home in the soil and it doesn't need direct sun for at least 3 weeks. If you purchase during the summer I would recommend planting out of the sun during the summer or until you start to see new growth from them being planted in the new soil.
Lets talk about your soil! 30% sand and do not keep your soil moist. Moist soil will kill the feeder roots. It is like us being in the hot tub to long and your fingers get waxy. The same thing happens to the feeder root. As they are trying to get established, the moist soil kills off the new roots trying to develop. If you see no growth or have further questions do not hesitate to call 919-696-0328.
The reason they will not start to grow is usually a moisture issue and most of the time the soil was kept moist. So please watch your moisture. A plant that arrives stressed does not need to be watered every day. Just good soil with a little moisture in a comfortable place to grow.