How To Grow And Care For Ginkgo Trees
Roger Foley
One of the oldest tree species on the planet is the ginkgo (Ginkgo biloba). This deciduous tree is called the maidenhair tree, a conifer living fossil. Though these trees once grew wild in North America, they are now native only to a few parts of China. Buddhists beautified their temple gardens for centuries with ginkgoes, some of which are over a thousand years old. Admired worldwide, individuals plant these slow-growing trees to showcase their fan-shaped leaves that turn bright yellow in the fall. In some cases, Ginkgo trees are used as supplements for memory improvement. There can be adverse effects when interacting with specific drugs, so you should always consult medical advice. Female ginkgo tree seeds are toxic to humans and pets, causing gastrointestinal issues.
Plant Attributes
Common Name: Gingko, Ginkgo, Maidenhair
Botanical Name: Ginkgo biloba
Family: Ginkgoaceae
Plant Type: Perennial, Tree
Mature Size: 50-80 ft. tall, 30-40 ft. wide
Sun Exposure: Full, Partial
Soil Type: Loamy, Sandy, Moist, Well-drained, Clay
Soil pH: Acidic, Neutral, Alkaline (5.0-8.0)
Bloom Time: Spring
Flower Color: Green
Hardiness Zones: Zones 4-9 (USDA)
Native Area: Asia
Toxicity: toxic to pets, toxic to people
Ginkgo Tree Care
Ginkgoes are versatile and resilient. They are street trees that can train to be bonsai. Female trees have foul-smelling, fleshy seeds, so choose male selections. What began in 1929 as a scientific experiment became something breathtaking. Dr. Orland E. White, the first director of the Blandy Experimental Farm in Boyce, Virginia, wanted to sprout seeds from a single tree, knowing ginkgoes can be either male or female.
He theorized a single tree's sprout seeds would have a one-to-one ratio of male-to-female saplings. Dr. Orland E. White and his students used seeds from a ginkgo tree on the University of Virginia campus in Charlottesville to germinate and plant more than 600 saplings at the Blandy site. Dr. White was right, and now 300 trees remain—America's most extensive planting of ginkgoes for research in The Ginkgo Grove.
Light
Plant Ginkgos in an area that receives at least four hours of direct sunlight daily. These trees thrive in full to partial sun.
Soil
Ginkgo trees grow in various soil types, including a pH range of acidic to alkaline, loamy, moist, rich, clay, and sandy soils. These trees prefer moist, well-drained soils and grow best in sandy soil. They are also tolerant of compacted soil making them a good choice for urban areas. Ginkgo trees are suitable for coastal areas but also grow well as street trees since they are resistant to air pollution.
Water
Fairly drought-resistant once established, Ginkgos should keep moist soil during its first few years of growth—water a few times a week.
Temperature and Humidity
Avoid planting Ginkgos in consistently hot, dry climates. These trees need proper watering to thrive, especially when establishing roots. Areas with a temperate climate—not too hot in the summer or cold in the winter—are best.
Fertilizer
It's best to fertilize the planting hole before growing a new Ginkgo tree. Plant these trees in the spring for the best results. A balanced, slow-release fertilizer will help encourage new growth, but mature trees don't require anything.
Types of Ginkgo Trees
'Autumn Gold' grows 30 to 50 feet tall and wide, making it an excellent choice for a significant impact.
'Gold Spire' grows 15 feet tall and five feet wide in a more columnar shape, which is better for tight spaces.
'Jade Butterflies' grow in a V-shape about 12 feet tall and 10 feet wide.
'Troll' is a dwarf variety best for container pots as it grows three feet tall and wide.
Pruning
Ginkgo trees only need pruning once a year during their dormancy in late winter. Remove competing branches with a sharp garden shear. Since these trees mature to have large canopies, you can choose to narrow their shape. Alternatively, Ginkgo trees can also cultivate into Japanese bonsai.
Propagating Ginkgo Trees
Propagating Ginkgo trees is most straightforward when using stem cuttings. Here is how:
Start by cutting the tip ends of growing branches in the summer. Use a sharp knife or pruner to cut a six to seven-inch long branch. Remove stems from male trees as the female trees produce foul-smelling seed sacks that won't yield good results.
Place branches in a container filled with loose soil or rooting mix. Make sure there is at least two to four inches of soil.
Add a rooting hormone to the soil mixture for additional support.
Water cutting, so the soil remains moist, but also use a system that has proper draining. The soil should not be too wet.
Continue watering for six to eight weeks until new growth takes root.
Plant in an area with partial to full sunlight in the spring.
How to Grow Ginkgo Trees From Seed
Since female seeds can complicate the growing process, using male cuttings to start new growth is recommended. It is still possible to grow Ginkgo trees from seeds, but it is a more advanced process. Here is how:
Start with Ginkgo seeds from an existing tree dropped fruit, or a gardening supplies store seed starting packet.
Seeds need exposure to cold temperatures before planting so germination can occur—Place seeds in a refrigerator or moist, sandy container pots outside during the winter.
Remove seeds and place them in a horticultural soil mixture containing sand or sand and perlite. Additional soil options include peat moss or vermiculite.
Plant seeds in a few inches of soil. Cover and keep in a warm location with moist soil for one to two months. You can remove seeds once you see sprouts.
Finally, plant new growth in its final location or continue to grow in a container.
Overwintering
Ginkgo trees are winter-hardy trees and should survive in moderate temperatures.
Common Pests & Plant Diseases
Mature Ginkgo trees are relatively resistant to pests and diseases. New growth's bark is susceptible to snails, slugs, mice, and other problems, but appropriate insecticides can help manage it.
Additionally, trunk disease, such as Neofusicoccum parvum, is a fungus that you can treat with appropriate fungicides if it infects your trees.
Common Problems With Ginkgo Trees
Root Problems
Common root problems like root-knot or root rot affect Ginkgo trees. Root-knot nematodes are tiny worms that prevent this tree from absorbing all the necessary soil nutrients. If you see this issue, add more soil nutrients, such as compost or peat moss, to the soil to help make up for some of the deficit. The soil-borne disease, root rot, can also happen when mismanaging soil nutrients or watering habits.
Problems with Fruit
Female trees drop fruit described as having a foul, sickly-smelling odor about the size of a cherry. To avoid dealing with this, choose male species of Gingko trees that do not bear fruit.