How to Revive Green Giant Arborvitae?

 Thuja green giant arborvitae turning brown is part of the plant’s normal growth cycle. The green coloration typically returns in the following growing season. However, if trees remain green, and green-colored needles fall off, that may indicate a problem.

If green giant arborvitae remains green and green-colored needles do not fall off: 

Watering green giant arborvitae frequently with water such as rain or tap water (if you use fertilizer on your green giant arborvitae tree make sure it is suitable for green giant arborvitae trees) give sufficient water to green giant arborvitae. 

If the Green Giant Arborvitae tree is planted in full sun, it should be given supplemental irrigation if rainfall is less than 1/2 inch per week during its first two or three years after planting. After that period, green giant arborvitae trees are established and can tolerate drier conditions without additional irrigation. 

Watering the green giant arborvitae root ball when green giant arborvitae is planted assists green giant arborvitae in establishing a healthy root system. If green giant arborvitae trees are not watered, the green giant arborvitae root ball dries out and this may be harmful to green giant arborvitae health. However, green giant arborvitae should never be over-watered.

If green giant arborvitae tree remains green but green-colored needles fall off: 

Fertilizer requirements for green giant arborvitae vary depending on where it is grown. Green giant Arborvitaes require less fertilizer in acidic soils compared with alkaline soils, so green giant arborvitae may require little or no fertilizer when green giant arborvitae is grown in acid soils. Green giant arborvitae is sensitive to nickel, so green giant arborvitae needs less nitrogen in the soil if green giant arborvitae is grown where there is low nickel content in the soil. Green Giant Arborvitaes do not require additional fertilizer if green giant arborvitae trees are fertilized every year with a slow-release, balanced fertilizer that contains micronutrients. Application rates of slow-release, balanced fertilizer for green giant arborvitaes varies by product and should be followed on the label, but rates typically range from 3 – 9 lbs per 100 sq. ft.

Green giant arborvitae green needles turn brown and green-colored needles fall off:  

If green giant arborvitae remains green but green-colored needles on green giant arborvitae turn brown and drop from green giant arborvitae trees, the following may be factors:

• Root Problems – If green giant Arborvitaes have been recently planted or transplanted they may suffer from root problems. Root rot due to soil damage from construction equipment can also cause those symptoms below ground, and this should be considered if your green giant Arborvitae were newly installed.       
• Pest Damage – Gall adelgids produce a substance that results in green-colored needles turning brown and dropping off green giant arborvitae.
• Cold Damage – If green giant Arborvitaes were recently planted or transplanted, green-colored needles may fall off green giant arborvitae

If green giant Arborvitae tree remains green but green-colored needles turn brown and fall off:   

• Supplemental irrigation can help green existing foliage after transplanting if trees are planted during warm periods. Fertilizing the green giant arborvitae root ball assists green giant arborvitae in establishing a healthy root system. After roots have developed so that green giant arborvitaes can tolerate drier conditions without green giant arborvitae showing damage, green giant Arborvitaes should not require additional irrigation.

Yellowing of green-colored needles on green giant Arborvitae trees may be caused by the following: 

• Cold injury– resulting in green giant arborvitae needle yellowing and premature dropping is common on green giant arborvitae that is newly transplanted or recently dug up for transplanting. This causes only temporary damage to green giant Arborvitae trees, but if green Giant arborvitae was recently transplanted or recently dug up, it should be watered regularly until green giant arborvitaes can develop a healthy root system so this does not become an issue.
• Insects – green-colored needles on green giant Arborvitae turn yellow and green giant arborvitaes scratch the underside of green giant arborvitae leaves to show signs of green-colored needle insect problems. Green-colored Needle Insect Problems – If green giant arborvitae begins scratching green-colored needles under green Giant Arborvitaes is not a sign that those green-colored needles are falling off but rather, green color indicates damage from the feeding of small insects or eggs laid by those insects.
• Fertilizer burn – If green giant Arborvitae turns yellow after fertilizing it has suffered fertilizer burn, which causes discoloration and leaf drop, in green giant Arborvitae. The green color of green Giant arborvitae in green-colored needle insect problems is not the same as the green-colored needles burning and turning yellow after fertilizer use.
• Root rot – If green giant arborvitae turns yellow or green colored needles fall off green giant arborvitaes that are planted or recently transplanted, roots are damaged, causing root rot symptoms that indicate trees should be dug up to determine the extent of the damage.
• Fertilizer Problems – When green Giant Arborvitaes turn yellow it may be due to over-fertilizing or applying high rates of nitrogen-rich fertilizers, which often causes leaf drop. Green-Colored Needle Insect Damage – green-colored needle insect problems can be caused by green Giant Arborvitae gall adelgids that irritate green giant Arborvitae needles, causing green-colored Needles on green arborvitaes to turn yellow. If green Giant Arborvitaes scratch green-colored leaves under green Giant Arborvitaes, leaves may turn yellow and drop off green giant arborvitae due to irritation from feeding damage by small insects. Over-fertilizing – If green giant Arborvitae turns yellow after recently being planted or recently transplanted it has suffered fertilizer burn which discolors foliage in Green Giant Arborvitae, causing slow growth near the tips of stems, stunted branch development.