What Can You Do to Make Thuja Giants Grow Faster?

Planting Site

• Although Green Giant and other cultivars of arborvitae are quite tolerant of a wide array of soils, they all grow better and faster in crumbly, fertile soils that are moist but well-drained. All soils benefit from being amended with organic matter to improve porosity and fertility. Locate the Green Giant arborvitae where it will bask in six to 10 hours of direct sunlight daily. Too little sun reduces photosynthesis and slows the growth rate, as well as creates a nonuniform habit. Grow it in U.S. Department of Agriculture plant hardiness zones 5 through 8a.

Irrigation

• An evenly moist soil year round ensures the Green Giant's root system is robust and healthy. Watering the root ball of a newly planted arborvitae is vital to keeping the plant alive and promoting root growth outward into the garden soil. As long as the soil isn't frozen, irrigating to supplement natural rain or melting snow prevents any growth disruption from drought stress. However, do not over-water, creating a soggy soil, as it leads to root rot and fungal problems. Disease can kill roots and leaf tissues, further slowing growth.

Mulch Benefits

• Maintaining a 3- to 4-inch layer of organic mulch over the soil and root zone of the Green Giant arborvitae provides many benefits. The mulch decomposes to supply trace nutrients to roots for better growth. Mulch also shades the soil in summer to keep it cooler, conserves moisture and prevents weeds from growing and competing for resources. Keep the mulch 4 to 6 inches away from the arborvitae's trunk. This ensures there's good air circulation at the trunk so fungal diseases or rot don't occur.

Fertilizer Insight

• Because the Green Giant arborvitae already grows quickly when experiencing ideal growing conditions, relying on fertilizers isn't mandatory. Slow-release granular fertilizers are more important to use on sandy soil types, as water leaches the nutrients more quickly than in loam or clay. Do not rely on water soluble "liquid feed" fertilizers. Scatter well-balanced fertilizer granules in very late winter and again in late spring to promote lush, healthy branches and foliage. Avoid over-fertilizing, since the salts in fertilizer products can burn roots if in the soil in excessive amounts.