Answer: Arborvitaes are known for changing color in the winter, usually they turn what is called a bronze color. In spring they eventuallty green up again. (The first time I grew arborvitae I thought they were dead by spring, but they were not dead at all!) Some people consider this seasonal change attractive while others do not. Depending on the variety you planted, yours may or may not do that because some of the newer types maintain a good green year round.
Arborvitaes are also known for developing browned foliage each fall, this time at the interior of the shrub. This is also a normal part of their development and growth as long as it is limited to the interior portion of the plant.
Arborvitaes grow best in full sun. If they are planted in a shady area, they will eventually grow thin and sparse and look poorly.
The best way to assure success with newly planted arborvitaes is to plant them in full sun with adequate spacing between them, mulch with several inches of organic mulch year round, and water as needed to keep the soil evenly moist like a wrung out sponge for the first year while they become established. After, that, water during dry spells as this is a plant that dislikes dried out soil. Provide a wind break the first winter or two if they are in a windy location. Be sure the soil is damp in the fall so they are well hydrated going into winter when the ground freezes.
Take care not to overfertilize, it is a moderate to slow grower and excess fertilizer will not improve that. I hope this helps.
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