Deer are a big problem for gardeners in many areas of the country. While there are a plethora of home and commercial remedies and deterrent methods available, it can be hard to differentiate between them and know the best overall strategy to use.
One group that has been researching deer damage on its property for more than 20 years is the Institute of Ecosystem Studies in Millbrook, New York. The institute's mission is to create and disseminate information on maintaining healthy ecosystems. Deer browsing is having a detrimental impact not only on gardens, but on forest ecosystems as well.
The Institute has been monitoring deer damage on almost 2000 acres to determine preferred plant species and the effectiveness of various home and commercial products and methods for deterring deer. They've found that deer change their diet seasonally, eating broadleaf evergreens (such as rhododendrons) and conifers in winter, but ignoring them in summer in favor of more succulent plants, such as hydrangeas, weigela, and mock orange.
They've found that scent-based repellents work best when used before browsing begins and when used in abundance to overwhelm an area with a scent. The most effective approach is to combine scent and taste deterrents, however if your area is experiencing a combination of drought, poor tree nut production, and high numbers of deer, you're likely to find deer damage no matter what you do.
For information on controlling deer damage, types of fences to use, and perennial and woody landscape plants least likely to be browsed by deer, go to: Institute of Ecosystem Studies.