I have Leyland cypress, roughly 15-20 feet tall. They are starting to brown this spring after Superstorm Sandy blew through this past October. What could be the cause and solution?
The Gardener’s Answer
Hello, Ray in New York: As spring weather arrives the truth will be told about landscapes subject to Superstorm Sandy. Since your evergreens are just starting to show signs of stress they may be salvageable. It really depends on how much salt they were exposed to; some plant species are more tolerant of higher levels of salt than others. The good news is that once established, Leyland cypress (Cupressocyparis Leylandii) are tolerant of salt spray. Unfortunately, in most cases once the foliage on an evergreen turns brown, they do not put on new growth to replace the lost. The fear is that the increase in salt levels has dried out the roots. I assume these were happy established plantings before the storm hit, so at this point it is important to find out why the foliage is turning brown. You can have your soil tested for soluble salt levels through the Rutgers soil testing lab. You can visit them at http://njaes.rutgers.edu/soiltestinglab. You can also call your County Cooperative Extension Service to see if they offer this service as well. It would be beneficial to know the salt levels and if this is the reason for the decline in your cypress. If so, gypsum can be effective in removing salt from soil. I realize you are in New York but there is an informative publication provided by the Ocean County Extension Service in New Jersey on landscape plants after the storm: http://ocean.njaes.rutgers.edu/documents/copingwsaltwtrNov28.pdf. It is never a bad idea to have a certified arborist come out and take a look at your cypress just to make sure you are not dealing with any insect or disease issue.