Holly Tree Care
We purchased a home in Fayette Co with two 25 foot Holly Trees. One is shaped perfect, the other is not. It has not been shaped or trimmed. Do we need both trees to produce berries? What is the best way to trim or should we cut down? Both produce berries currently and continue to grow. How long do Holly trees live? We are guessing they are 40 years old or so.
Fayette County Kentucky
Thanks for your question to Ask Extension. You may wish to start with reading about the differences between English holly (Llex aquifolium) and American holly (Llex opaca) in this link: http://landscaping.about.com/cs/winterlandscaping1/a/holly_trees_2.htm About 10 paragraphs into this link is described a technique for pruning called 'hat racking'; it takes about 3 seasons to accomplish and is pretty aggressive yet reshapes a holly and fills it in. Additional pruning information can be found in HO-59, Pruning Landscape shrubs: http://www2.ca.uky.edu/agc/pubs/ho/ho59/ho59.htm . Be sure to click on the figures of interest to open them.
For the females to produce berries, a male tree must be available and within about 40 feet. Since both of yours are producing berries, look around for the male...in a neighbor's yard?
Please look at information on the Holly family at: http://dept.ca.uky.edu/PLS320/Lecture9Aquifoliaceae1.pdf . There are some good photos of holly cultivars and a section on the American holly (probably the one you have).
The holly genus is slow growing and some suggest Llex aquifolium (English holly) can "live to 500 years, though most don't live beyond 100". Kentucky's state champion American holly was a seedling in the early 1900's and is now 54 feet height with a trunk more than 7.5 feet around: http://www2.ca.uky.edu/KYWoodlandsmagazine/Vol_4_No_1/Big%20treepg%2016.pdf .
I hope this helps and if you have follow up questions, please let us know!