Why is my Arborvitae bush drying out?

May 26, 2022 Ask the Expert

Question:

I have an Arborvitae bush, about five feet tall, that was planted last fall.  Since the snow has melted, I’ve noticed that it is drying out. The most notable area is at the bottom of the bush, but it seems to be creeping up. I want to save it and need to know what to do. I have been putting about 4 gal. of water on it, per day, and have applied Miracle Gro twice during this season. It is planted in a dirt space that divides my asphalt driveway from my neighbors. It gets 2-4 hours of strong sun each day.

Answer:

Rebecca Long, Sustainable Agriculture and Horticulture Professional

With the proximity to your driveway, salt damage is definitely a potential cause. Arborvitae are moderately to highly sensitive to salt spray and salt in soil. You can protect bushes from being splashed with salt by wrapping with burlap, but to avoid salt damage through the soil you would need to switch to another deicing option for your driveway.

Damage like that can also be caused by strong spring winds drying out needles when the ground is still frozen and the plant can’t take up sufficient moisture. Lastly there are some fungal pathogens and insects that can cause damage to Arborvitae.

I would not add any more fertilizer, as fertilizer can contribute to salt issues in soil and make plants more attractive to certain insect pests. Any damage that is done cannot be reversed and you also want to avoid overwatering the plant and causing root rot. A few gallons of water per week should be sufficient, and only necessary when there is no rain.

If you continue to see more damage develop and you suspect an insect or disease, you can always send samples to our labs: insect diagnostic lab, plant disease diagnostic lab. Otherwise, I would give the plant some time to recover without too much further interference and maybe plant some flowers around the bottom to cover the most unsightly bits.