I have around thirty, 30 year-old Cypress Trees in my backyard that provided me with good privacy. I asked the advice from a landscaping
person and was advised that they needed to be killed and replaced with other plants for privacy. He informed me that if I would like to keep them trimmed they will not look good anymore and will remain brown. Can you advise if I really have to have them replaced? I would like to keep them and install drip irrigation for watering and an addition of compost to fertilize them. Please advise. Thank you. Will the 30 years old Italian Cypress trees still survive trimmings?
If they are basically healthy and just need light trimming, then yes, they can tolerate a moderate height reduction and shaping which can be done aesthetically by a good tree service. But if you top or side prune/shape too heavily then the interior dry foliage will be exposed and the branches may not regrow and may die back more severely.
Browning can be related to water deficit, drought stress, but also Italian cypress are susceptible to pests and fungal disorders that can only be controlled with pesticides, or sometimes even that is not effective.
If the problem is browning from water deficit, then deep watering right away may save them. Installing irrigation and a compost mulch as you suggest, will benefit them and may stimulate new growth.