Question
We have just planted three Norway Spruce trees (about 15' tall) and am wondering how much water these need and how often.  We are in Iowa and have adequate rains right along but it is mid July now and not the frequent rains of before.  I might add the soil was very wet where they were planted, even muddy.  Give me any advice please, thanks.
Also planted one river birch at the same time and wonder how much water it needs too and how often.  It was planted in a low spot with also very wet soil when planted.  The tree leaves have turned yellow and most fallen off but new buds are coming and getting larger each day.  We were hesitant to let the nursery plant these big trees but with all the rains around here they began planting anyway.  Do you give them much hope of growing?  Thanks Dale

Answer
Tow things going on here--this large a tree planted this late in the season will drop foliage due to the fact the roots system is much smaller than the foliage area and can not support the needs of the leaves so the tree drops its leaves. Also sounds like they got too much water. Too much water will cause the trees to drop leaves the same as too little.
I would check the soil around the trees before you add any water and see if it is dry down to about an inch deep. If so you can water but if it is predicted to rain I would let "mother nature" water. If the soil is dry and it is not going to rain I would water with 1 inch of water per week. Place a pan under the tree and turn the sprinkler on and when the pan has 1 inch of water in it stop, This is called deep watering and will cause the roots to grow deeper. If you have not done so mulch around the tree with not more than 3 inches deep of organic mulch not piled up on the trunk. About three feet around is good.