Silver Dollar Tree
Botanical name: Eucalyptus cinerea
Family: Myrtaceae (Myrtle)
Origin: New South Wales and Victoria, Australia
Height: 6 to 40 feet
As familiar a sight as eucalyptus branches preserved or fresh are in flower shops, I had never seen a plant growing in any of the gardens I'd visited. Then a few years ago, I found the seeds offered in a mail order catalog. I ordered a packet and, to my delight, produced a plant for my yard.
Because eucalyptus isn't hardy in our climate, it must be used outdoors here as an annual. And although the plant naturally wouldn't reach full size in one season, its growth rate is still so rapid that specimens produced from seeds started indoors in mid to late February should reach heights of 6 feet or more. That's enough to enable them to function as shrubs through the summer.
On a visit to the U.S. Botanic Gardens in Washington last summer, I was intrigued to find eucalyptus trees included in a special patio display. Planted in 24-inch terra cotta pots, they showed off to great effect.
Eucalyptus seeds should undergo a cold period for best germination. An easy way to provide that situation, says Holly Shimizu, a horticulturist and assistant acting executive director of the gardens, is to put the seeds in the refrigerator, planting them in 2 1/2 -inch pots in moist commercial potting soil and encasing the pots in plastic storage bags. Don't let the soil dry out.
After 6 weeks, remove the plastic and set the pots under fluorescent lights hung about 14 inches above them, or in a very sunny window. Raise the light tubes as the plants grow taller. In late April, plant the seedlings in the ground. Eucalyptus can stand a light frost, Ms. Shimizu says, but would need protection under an overturned pot or bushel basket if conditions were more severe.
To stimulate rapid growth, nourish plants once a week with a 10-20-10 liquid-type fertilizer applied at the recommended rate. Otherwise, a once-a-month dose is sufficient.
Eucalyptus loves hot weather, Ms. Shimizu says. At summer's end, when other plants are fading, it's in its element.