Answer: Arborvitae (eastern white cedar) is one of the hardiest evergreen landscape plants there is, but it does best where soils are moist. It's cold hardy to zone 3 once it's well established. Transplanting is pretty traumatic to most landscape plants, so they need extra TLC during the first growing season in order to settle in and be strong enough to make it through hard winters. Weekly watering is necessary when less than an inch of rain falls. An 8' shrub needs quite a root system to support all that topgrowth, so bone meal or other phosphorus-rich fertilizers that promote root growth should be applied to the backfill at planting time. Smaller shrubs don't have such an imbalance of top to root, and often adjust better to transplanting.
Continue to water into the fall, since dry winter winds literally suck moisture from plants, and when roots are dormant in winter, they can't replenish that moisture. Fall watering ensures that the foliage has plenty of moisture to spare. You may be able to save your shrubs - have the nursery that sold you the shrubs assess their health, and make a plan for recovery. Hope this helps!
Q&A Library Searching Tips