Plant Profile: Citrus

By Craig Huegel

Reprinted from The Understory, Aug.–Sep. 1998

Although the early Spanish explorers brought oranges, limes and lemons to Florida, there already were trees here from the citrus family. Our native citrus, however, were much different trees and their familiar relationship to oriental citrus varieties likely escaped their notice. Most noticeable was the lack of succulent fruit. Citrus native to Florida produce hard dry seeds enclosed in a papery sheath. They would never be cultivated for human food. Regardless of this fact, our native citrus do have great value in the landscape and should be considered as potential candidates in a landscape plan.

One attribute shared across family lines is that native citrus provide larval food for one of our most spectacular butterflies, the giant swallowtail. Giant swallowtail larvae, known also as "orange dogs," feed voraciously on the new leaves of all citrus family trees, and on nothing else. A citrus tree is a requisite of any butterfly garden designed to include the presence of giant swallowtails. All citrus also share the attribute of having highly resinous oil glands in the foliage. Crush the leaf of any citrus and you will be greeted by aromatic oils. Finally, most citrus also are thorny. Both the oils and the thorns are designed to protect them from browsing animals.

In this region of Florida, we have three species of native citrus that can be included in the home landscape. Other species, many of them quite rare, are native to extreme south Florida and the Keys. Below is a brief description of the three species native to central Florida.

Photo by Gil NelsonWafer ash (Ptelea trifoliata). Wafer ash is a small deciduous tree that rarely exceeds 20 feet in height. This is a most unique tree in many regards. As its scientific name implies, it is easily recognized by its 3-parted or trifoliate leaves (somewhat similar to the leaves of poison ivy). The leaves and even the bark are especially strong scented, being rather musky and not "citrusy" s might be expected. Wafer ash gets its common name from its fruit. They are samaras, similar in size and shape to those produced by maples and ash trees, but rounded and without the long tail. This tree is native to rich woodland habitats across northern Florida to central Florida. although not native to Pinellas, it does occur sporadically in counties at our latitude. If you wish to use this plant in your landscape, do not plant it in full sun and make sure that it gets a little extra nutrition.

Photo by Shirley DentonToothache tree (Zanthoxylum clava-herculis). Toothache tree or Hercules-club is a very adaptable and fascinating tree for the right landscape setting. Tardily deciduous, this tree is easily recognized by its exceedingly spiny trunk, general lack of side branches and its tuft of deep-green shiny leaves on top. Its common name comes from the practice of native Americans and early settlers to use it as a toothache remedy. To see how this works, take a new leaf and chew it. In just a few minutes you will find that your lips and gums have gone numb, deadening for the moment any toothache pain. This tree is native to north and central Florida, generally in well-drained uplands. Given really poor drainage, it will either die to the ground or die completely. However, toothache tree will tolerate a wide ariety of soil, sun and drainage types. It is also salt tolerant. Its unique shape and character make it an interesting accent plant in the landscape. Just don't use it in an area where its spines will cause you trouble.

Photo by Allen BoatmanWild lime (Zanthoxylum fagara). Wild lime is an evergreen tree that may reach 30 feet in height. This is a wide spreading tree, much like a live oak, but on a much smaller scale. Its foliage is normally yellow-green in color and the leaves are composed of rounded leaflets. Although wild lime is not as spiny as its cousin above, it does have many small hooked thorns along the branches. Wild lime is more common in hammocks of south Florida, but it does occur naturally in our latitude. It may suffer some cold damage in temperatures in the low 20s, but otherwise it does well in Pinellas. This small tree makes an interesting accent plant in the landscape or blends in well in a mixed woodland setting. It is very adaptable and will grow in the conditions described above for the toothache tree.

Published on  07.30.2012