There are approximately 700 known species of eucalyptus, the majority of which are native to Australia and are therefore best suited for tropical climates, though some cultivars might be able to survive in USDA zone 7. Growing eucalyptus in pots is an option to consider if you live outside of the eucalyptus hardiness zone. Some types of eucalyptus can also be grown as annual plants.
Characteristics of Eucalyptus
Also known as gum trees because of the resinous sap they ooze when cut, eucalyptus are fast-growing evergreen plants. Some eucalyptus are towering trees capable of reaching 200 feet in height, while others grow as shrubs. The leaves of eucalyptus plant are extremely fragrant due to the high oil content of their leaves. The oils are used medicinally as well as in beauty products. The presence of oil in eucalyptus leaves can potentially make these plants a fire hazard.
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Growing Eucalyptus in Zone 7
Some eucalyptus cultivars have showed an ability to survive cold temperatures outdoors in USDA zone 7, including the Angus eucalyptus (Eucalyptus nicholii 'Angus'), a cultivar of the willow-leaved peppermint eucalyptus, and the Big O eucalyptus (Eucalyptus neglecta 'Big O'), a cultivar of the omeo gum.
Another option for growing eucalyptus in USDA zone 7 is to treat the plant as an annual. A few silver-leaved eucalyptus species make great annual plants, including the Silver Drop eucalyptus (Eucalyptus gunnii 'Silver Drop'). This cultivar of the cider gum, considered one of the hardiest eucalyptus, is a compact option that achieves a height between 2 and 3 feet in a single growing season.
The silver dollar gum (Eucalyptus perriniana) and the argyle apple (Eucalyptus cinerea) are also well-suited for growth as annuals because of how quickly they grow. In fact, when grown from seed, these trees can reach a height between 6 and 8 feet within a few months.
Growing Eucalyptus in Pots
In zone 7, you can also grow eucalyptus in containers. Given the size of these plants, it is important to use a large container capable of holding the shrub as it matures. The containers can be kept in a sunny outdoor location in the summer and transferred inside before the first frost of the fall. Both the silver dollar gum and the argyle apple can be grown in containers.
Eucalyptus perriniana is sometimes kept as a houseplant. If you go this route, you'll want to keep your eucalyptus plant near a window where it will receive six to eight hours of direct sunlight a day. When choosing a location for your indoor eucalyptus, note that the ideal temperature for these plants during the growing season is 65 to 75 degrees Fahrenheit. Eucalyptus plants need a lot of water, especially when grown in pots, so it is important to provide consistent moisture during the growing season.
In the winter, prune your eucalyptus indoor plant in order to maintain a bushy appearance. However, be warned that even with regular pruning, a fast-growing eucalyptus plant, like the silver dollar gum, can easily outgrow its container in a short amount of time. In the winter, hardy varieties of eucalyptus must also undergo a dormant period with reduced watering and temperatures between 45 and 50 degrees Fahrenheit.
- Missouri Botanical Garden: Eucalyptus cinerea
- Missouri Botanical Garden: Eucalyptus perriniana
- University of Arkansas Division of Agriculture: Plant of the Week: Hardy Eucalyptus
- Better Homes and Gardens: Eucalyptus
- New York Botanical Garden: Eucalyptus Houseplants
- Wilson Bros Gardens: The Most Cold Hardy Eucalyptus Tree Varieties For Growing Outdoors
- The United States National Arboretum: USDA Plant Hardiness Zone Map
- Avant-Gardening: United States Frost Zone Map