March 2013 Plant of the Month: Eucalyptus

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Submitted by James Newburn, Assistant Director, UT Gardens, Knoxville

 Our plant of the month for March is actually appealing all year long. That is because Eucalyptus neglecta, commonly called Omeo Gum, is an evergreen that maintains its foliage year round. It also has the familiar blue-green eucalyptus foliage with round- to oval-shaped leaves and the delightful, distinctive fragrance. These features make it ideal not only as a specimen tree but also as a source for cut branches that can be dried and used in arrangements. 

Native mainly to Australia, many of the eucalyptus species do not tolerate frost, much less a freeze. Eucalyptus neglecta, however,is a hardier species and is listed as being winter hardy to zone 7. The specimen in the UT Gardens, Knoxville, which is in zone 6b, has been in the ground for six years and is thriving. It has reached a height of 16 feet in that short time and is considered a fast-growing plant. It does well in full sun but will tolerate partial shade. 

To add to the attributes of this beautiful tree, let’s take a look at the species name neglecta. Any plant whose name implies it doesn’t need much care is a winner in my book. At the UT Gardens, Knoxville, we have certainly found this to be the case. Omeo Gum can tolerate many soil types including our heavy clay soil.Once established, it is considered a water-wise plant needing little supplemental watering in our region. It’s ideal to use in a xeriscape landscape or in an area where irrigation or the hose does not reach. 

Although the Omeo Gum does have a white flower, the blooms are so inconspicuous that you may not even notice them. However, the foliage is striking. Not only does it have the beautiful leaf color, but the leaves and stems of the new growth are tinged with shades of pink. Speaking of leaves, eucalyptus trees have juvenile and adult leaves. Until the plant reaches about 12 to 15 years old, the leaves are the round shape we associate with dried arrangements. As the tree further matures, new foliage will be narrow and strapped shaped and equally appealing. As a fast grower the tree can reach a height of 20 to 40 feet in 15 to 20 years and can ultimately reach a height of 60 feet. As it ages the bark becomes another an outstanding feature, peeling off to give the tree a shagbark appearance. 

Eucalyptus has long been valued for its aromatic properties and has been used medicinally as an antiseptic and for respiratory ailments. The leaves are popular for use in potpourris and flower arrangements and wreaths as well as for extraction of their essential oils. Even if you never use the cut foliage, the many fine characteristics of Eucalyptus neglecta warrant its use in the landscape and earn it the title “Plant of the Month” not for one month but for all twelve.  

James Newburn is assistant director of the UT Gardens, Knoxville. The UT Gardens located in Knoxville and Jackson are part of the University of Tennessee Institute of Agriculture. Their mission is to foster appreciation, education and stewardship of plants through garden displays, collections, educational programs and research trials. The gardens are open during all seasons and free to the public. See http://utgardens.tennessee.edu/ for more information.

Contact: James Newburn, UT Gardens, Knoxville, 865-974-8265