Holly-Tone does mention evergreens in their product label. However, they also mentioned that the formula of the fertilizer works best for acid-loving plants. As mentioned by the manufacturer on their website, you should opt for the Plant Tone since arborvitaes and Boxwood are not acid-loving evergreens.

What is the best fertilizer for arborvitae?

Best Fertilizer For Arborvitae

We recommend using slow release fertilizer that has 50% nitrogen and has a high first number, like a 12-6-4 or 10-8-6 mixture. Granualized fertilizer works the best because it helps prevent the roots from burning and allow you to only fertilize once per year.

Is Holly-tone good for Green Giant arborvitae?

Arborvitae are not acid-loving trees and the use of Holly-tone on Green Giants is not recommended, sice it boosts the acidic level of the soil. Organic Plant-tone is recommended instead. ... If it is between 6.0 and 8.0, your tree will do fine.