Question
Good morning and thank you for your help. Please bear with me and my scientific background if I give you too many details: Three weeks ago, I planted five 2-ft-tall, healthy T. orienthalis (Arborvitae aurea nana variety) in Dallas, Texas. The shrubs were planted in (but near the edge of) a lawn where St. Augustinegrass grows, about 3 ft. from the asphalt street that limits the lawn. Mulch and root stimulator were applied (the latter perhaps 3-4 times more generously than the label indicated). The arborvitaes receive almost full sun, but watering may not have been optimal, as it has been unusually hot here and the sprinklers barely reach the edge of the lawn where the shrubs are planted. Two adjacent shrubs have developed brown (dried) leaf tips, spanning about 3-6 mm from the tip into the branch. I have seen no obvious infestation or fungal infection signs and wonder if the watering has just not been enough, but I am intrigued by just the tips of these two arborvitaes bearing the problem and not the entire set of shrubs, or even broader parts of each plant, if dehydration is to blame. Thanks.

Answer
Sounds like a couple of things--when a plant is first planted it is under a great deal of stress and it sometimes will wilt. The wilting will be on the ends of the branches. Watering properly will lessen the effect of stress.
Normal watering means that soil should be kept evenly moist and watered regularly, as conditions require. Most plants like 1 inch of water a week during the growing season, but take care not to over water. The first two years after a plant is installed, regular watering is important for establishment. The first year is critical. It is better to water once a week and water deeply, than to water frequently for a few minutes.
For new plantings water every week with 1 inch of water (place a pan under the tree and turn the sprinkler on and when the pan has 1 inch in it stop) do this only if it does not rain.
If you have not done so mulch around the trees with not more than 3 inch deep of organic mulch (pine straw works well). This will help hold moisture.  Do not pile the mulch up on the trunk of the tree. Do not fertilize for the first year.