What is best type of fertilizer for techny arborvitae which is in 2ft. of black dirt

Asked August 19, 2016, 9:08 PM EDT

Hi- What is best type of fertilizer to use for techny arborvitae which is in 2ft. of black dirt and that dirt is on top of clay soil? I have received conflicting recommendations from Bachmans about this...can you help? Thanks, Charles

Hennepin County Minnesota

1 Response

Thank you for the question. The best indicator of whether fertilization is necessary is a soil test. A tree or shrub that has good color, is growing well, and is free of disease or pest problems probably doesn't need fertilization, especially if it is growing in a landscape with turfgrass that is fertilized regularly. A soil test will tell you exactly what is needed and here is how to do it: http://soiltest.cfans.umn.edu/

If you decide not to do a soil test, use a general fertilizer with a ratio of three parts nitrogen, one part phosphorus and one part potassium. Do not fertilize now because new growth may be stimulated that won't have time to harden off before winter. Spring is the best time.


Thank you for contacting Extension.