GInkgo trees may be the oldest species in the garden, but they won't likely be the fastest growing one. Ginkgoes (Ginkgo biloba) have been around since the dinosaur days and are beautiful, resilient specimens. During their maturity, they can grow as fast as 1 to 2 feet per year.
The term "unique" is overused when it comes to garden trees -- but it applies with full force to ginkgoes. Fossils establish that the species has been around for some 300 million years, virtually in the same form we admire today. The ginkgo's fan-like leaves, green in summer then canary yellow in fall, are unlike those of any other tree. The smelly fruit borne by the female ginkgo is also one-of-a-kind. Ginkgo trees grow best in U.S. Department of Agriculture plant hardiness zones 5 through 9.
Size and Growth Rate
Make no mistake, species ginkgoes are tall trees, growing up to 90 feet in height with a 60 foot spread. If you want a small, shrubby tree, you'll need to look for a dwarf cultivar. The trees can live well over 150 years, and some still alive today are over 1,000 years old. Over that long lifetime, the growth rate varies. Compared with other landscape trees, it's safe to say that the ginkgo has a modest growth rate, which averages between 1 and 2 feet per year.
Growth Periods in Ginkgoes
The years after planting constitute an establishment period for the ginkgo. During the first five years, it's likely to grow very slowly, as it spends its energy putting down roots. After the tree is established in the landscape, the growth rate speeds up. From that point until it reaches about 40 years of age, it may grow 24 inches a year. Female trees start bearing seeds at sexual maturity -- between 20 and 40 years old -- and their growth rate declines while they use their resources for seed production. This does not occur with male trees, and these are the ginkgoes with the fastest growth during their first century or so. Both male and female trees slow down after their first 150 years.
Stress-Free Ginkgoes Grow Fastest
Ginkgoes grow fastest and live longest in proper growing conditions free from stress. They prefer to grow in full sun in warm, moist, well-drained soil ranging from neutral to slightly acidic. Although the species is touted as tolerant of urban pollutants, the trees grow fastest where the air, soil and water are free from toxins. Likewise, despite their drought-tolerant reputation, ginkgoes develop faster if they have access to regular water during the growing season.