Do ultrasonic deer repellants work?


Do ultrasonic deer repellants work? We have a string of arborvitaes which the deer love to munch on in the wintertime. Is fencing the only other alternative? We have tried sprays and clip on deterrents but nothing like that works.


Jonathan Foster, Special Projects Assistant

The short answer, in my experience, is that none of the products marketed for this purpose, or the truly ingenious ideas gardeners and homeowners have come up with over the years to deal with browsing deer, are effective in the long term. Deer are voracious, persistent mammals who eventually adapt to just about everything other than physical separation from the plant you want to protect. There is evidence to suggest that some deterrents can mitigate the feeding damage, but they wash off easily and must be reapplied frequently and thoroughly; even then, they won’t be 100% effective. The other thing you can do, moving forward, is to select deer resistant plants so as not to attract them to your yard. Obviously, that won’t help with your arborvitae, but it’s good to keep in mind that you have deer when purchasing other plants or doing landscaping. Fencing (including possibly electric) is the only sure fire way to keep the deer out of your yard and garden.

Read more in this great resource from the UNH Extension.