Most of us have heard the saying "variety is the spice of life".  When it comes to the landscape, this saying also applies. If you look at a farmer who plants thousands of acres of all one crop, commonly called a monoculture, they can have major outbreaks of either insect pests or diseases. Research has shown that a landscape with diversity in its plant material has fewer problems because beneficial insects can do a better job of keeping everything in balance and therefore under control.

So, when you are planning to put in another tree or shrub you may not want to go with something that you or your neighbor have already planted. Dr. Ed Gilman, a specialist at the University of Florida, recently wrote an article in the Florida Arborist talking about this same topic. Dr. Gilman mentioned in his article that in his mind there is no question that our native Live Oak is over planted in Florida. He goes on to state that this same type of situation was responsible for disasters of catastrophic proportions in other parts of the county. For example, our native American Elm was over planted in the late part of the 19th century and the early part of the 20th century in North American communities from coast to coast. In the decades following the appearance of Dutch elm disease, nearly all elms in most communities were wiped out. More recently, the ice storm in Montreal and upper New York one year ago taught some more hard lessons. More than 70,000 of the 130,000 street trees in the city were severely damaged. The situation was made worse because "72% of the street tree population was comprised of only 4 tree species" according to Michel Labrecque, Curator of the Montreal Botanical Garden. He noticed that in areas where street tree populations were diversified, damage seemed less severe. I have also heard reports of a fungal wilt disease that is killing many of the large Live Oak trees in Texas.

In a recent issue of the Journal of Arboriculture there was a paper written on Assessing and Managing Street Tree Biodiversity. In their abstract they mentioned that due to compacted soils, impervious surfaces, heat irradiation, pollution and other stresses that urban trees have an average expected life span of 10-25 years. Many times when planning a landscape many jurisdictions rely on "approved tree" lists which rarely ever mention diversity as part of the document.

The results of this study suggests that no more than 30% of any one family, 20 % of one genus or 10% of one species should be present. This study was done looking at the street trees within a city but you could also use this recommendation for any subdivision, street, yard or even within an entire county.

If you are wondering about some other large trees that can be planted in the place of a live oak here are some suggestions: Southern magnolia (native), Florida elm (native), sugarberry (native), sweetgum (native), winged elm (native), and the Chinese evergreen elm. Now, don’t forget there are a number of other great trees that are medium or small in height. So, its really not too hard to get variety in your landscape when you look at all of the choices.

Do some research and learn the specific information on each tree such as height, spread, flower color, and light, pH & water requirements and you'll be ready to make a wise choice.