To care for an "Emerald Green" arborvitae, leave 2 to 3 feet of space between the tree and other plants, and make sure it is located under full sunlight. Plant the tree in well-drained soil with a 10-10-10 fertilizer, and prune only the sides of the tree.
Planting "Emerald Green" arborvitaes 2 to 3 feet apart allows space for proper maturing, prevents root crowding and reduces competition for water and nutrients between neighboring plants. The plant thrives in direct sunlight, so plant it in a location with little to no shade. Full shading and lack of sunlight causes the arborvitae to brown and eventually die.
Use a well-drained soil, and thoroughly water the plant. The arborvitae is an evergreen that must be watered often as it is not resistant to drought conditions, especially during the growing season. During droughts, be sure to water the plant more frequently.
A 10-10-10 fertilizer contains equals parts of nitrogen, phosphorus and potassium to boost the plant's growth. Use the soil in early spring, and then repeat the fertilizing process after the summer heat is over, during mid-fall. Do not fertilize the tree when it is being planted.
When pruning the tree, focus on the sides where stray branches have grown out too long or dead stems are hanging out. Avoid pruning the top of the tree so the plant can keep its naturally pointed shape, unless the height of the tree needs to be controlled.