Usually this means too dry or too wet. Sometimes it can also indicate a nutrient deficiency, as when hollies are making new growth and an excessive amount of existing leaves yellow and drop at the same time. There is not enough nutrients present to sustain a full top so some of the oldest leaves are lost in order for the new growth to live.

If your new trees cannot live in your existing soil in your climate then you will have to provide a different soil. A common way to do this in a simple way is to acquire more suitable soil, dump that on top of the existing soil and plant in the new soil. Where there is not a suitable situation for mounds or berms of topsoil then another possible solution is to excavate and replace the existing soil with better soil. This requires being able to remove and dispose of the existing soil. With trees quite a large area of existing soil needs to be dug out, preferably one as extensive as the entire potential rooting area of the trees.

Never dig out a small hole or pit of soil and plant long-lived subjects like trees and shrubs in liberally amended or completely replaced backfill soil. On damp clay soils in particular there is a likelihood of the modified backfill causing the planting hole to collect water during wet conditions. This is due to the difference in soil texture between the soil within the hole and the soil around it.

When plants are sitting in pockets of coarser material surrounded by less coarse natural soil there can also be a marked attraction of water to the finer soil during dry conditions. This is one of the reasons bare-rooting at planting time has begun to be advocated. Plants installed in natural soil with intact potting soil root-balls can be quite difficult to keep moist during dry weather, until they root into the natural soil.

thanks for the information. The trees look dry all the time I'm not to water them too much and I don't know how often the nursery watered them. silly question but what is the right amount of water that they should be getting?
As far as the ground we did soil to amend the planting area with. what is a good ratio in which to plant? SHould it be 50/50 or something else?
I appreciate any help you can provide.

"...what is the right amount of water that they should be getting?"

That depends on many factors like soil type, drainage, and weather and climate conditions. The best way to determine when to water is to stick your finger down into the soil and see if it's moist. The soil surface should be allowed to dry out in between waterings, but the soil 2" to 3" down should remains moist (not wet). Check the soil in AND around the rootball unless your tree was bare root when planted (probably wasn't). In some cases, the rootball can dry out even though surrounding soil remains moist (due to differences in rootball soil and native soil, surrounding the planting).

"As far as the ground we did soil to amend the planting area with. what is a good ratio in which to plant? SHould it be 50/50 or something else?"

It is almost always best not to amend the soil when planting shrubs and trees. Doing so greatly increases the chances of drainage problems and may impede proper root growth out into native soil.

Here is a link that might be useful: Planting a Tree or Shrub