Ginkgo trees are beautiful and amazing trees. These trees (Ginkgo biloba) are native to Asia and can be extremely long lived, as in over 1,000 years! In fact the ginkgo species existed at the same time as the dinosaurs. Ginkgo trees are also called the Maidenhair tree and have fan shaped leaves. In the fall the leaves turn an amazing golden color. In the span of a single day all the leaves will drop and litter the ground with a carpet of gold.
Ginkgo trees grow beautifully here in Tennessee. One day last fall I was dropping by my daughter’s school and saw the ginkgo tree out in the front of the school had dropped tons of seed all over the place. Ginkgo trees are either male or female (this is called dioeceous) and you need both for fertile seeds. Most of the time landscapers and horticulturalists recommend only planting male trees as you won’t end up with the messy and smelly fruit. As a gardener and plant propagator I look at that advice and think that’s a missed opportunity to make more trees!
How do you know if you have a male or female ginkgo tree? Male trees will produce a cone structure to send out pollen. This is because ginkgo trees are actually a gymnosperm (conifer). The female trees will produce the fruit which is basically a coated seed. It takes about 20 years of growth before you can tell if a ginkgo tree is male or female. As an odd quirk of the species some ginkgo trees can actually change their gender!
Collecting the Seeds
I collected the seeds which when I did resembled little nuts. The fleshy coating had already been removed by weather and time. This may be the key to good germination. Often growth inhibitors are in the flesh that surrounds various seeds. I can’t say for sure if this is the case but many people report that Ginkgo trees are difficult to grow from seed but I found a good germination rate in my first experience with growing them from seed.
Cold Stratification
When I brought the seeds home I placed them in a small plastic bag with a small amount of peat based seed starting mix and a little moisture (water) in the refrigerator. That’s where the ginkgo seeds stayed until I was ready to plant in the late winter. The process of storing in the refrigerator is called cold stratification and is meant to mimic the natural course of the seasons to help trigger good germination faster.
Starting the Ginkgo Seeds
I started the ginkgo trees about the same time as I started my tomato plants: about 8 weeks before the last frost date in our area. I used large plastic yogurt cups where I had cut a large hole in the top to leave a ring. I used a sterile seed starting mix for the medium, wet it down, then planted about 8 seeds in the pot. When sowing the seeds I sowed them at a depth about equal with the size of the seeds. I covered the pot with plastic wrap then used the ring to cover the container.
The Waiting…
After all that I put the newly planted ginkgo tree seeds on the plant shelves in my garage and waited. I use heat mats on my plant shelves (Am. Aff.) for better germination and because I need some kind of heat for starting my tomato and pepper seeds. Bottom heat is great for seeds as well as cuttings to help encourage the roots to grow. From here on out I checked every few days to make sure the moisture in the pot was good. With the enclosed environment of the yogurt cup I never needed to add more water until after germination when I removed the plastic from the cup.
Here you can see how well the ginkgo tree seeds germinated:
Potting Up the Ginkgo Seedlings
I gave the seedlings a few more weeks to grow with the plastic removed in the seed starting yogurt cup to get better roots and to see if any other seeds would germinate. I ended up with 4 seedlings total. Then I potted the seedlings up into individual pots. I used a potting soil mix I had and mixed that with with about 50% of composted wood chips. The wood chips add drainage and addition organic matter that will slowly break down.
In a week or so I’ll add some fertilizer to the pots to encourage some good branch and leaf growth. I will probably use some fish emulsion fertilizer and bloodmeal. I tend to stick with organic and natural fertilizers.
Softwood Propagation of Ginkgo Trees
This summer I hope to try taking some cuttings of another ginkgo tree. It’s a tree at my mom’s house that she and my dad planted several years ago. He passed away in 2011 from Cancer. While he was alive he planted a number or trees including oaks, maples, pecans, and a ginkgo. I would love to have a couple trees started from ones he planted to plant on our future home property as memorials to him.
My plan for propagating ginkgo trees is to take 4-6 inch softwood cuttings of ginkgo trees from terminal shoots in the early summer. (A terminal shoot is the end of a branch or a tip cutting.) Clear off all the leaves except for the top two. Dip the cut ends in rooting hormone and place in a damp medium. Cover with a cloche (I generally use a plastic bottle with the bottom cut off) and keep humid for 6 to 8 weeks. To keep the cuttings humid I’ve used the combination of the cloche and bottom watering in a closed hole (no hole) 1020 flat (Am. Aff).
If you have identified a tree as being male you can attempt to graft it onto seed grown ginkgo trees to make the new seedlings become male trees and avoid the future smelly seed production issues.
I’ll make it a point to visit my daughter’s school about the same time next year and see if I can gather more seeds and try this again this fall and next spring.
I am really excited to see these new ginkgo trees grow into strong trees that will out live me and will probably out live many generations of our family. There is something extremely special about planting a tree that will endure the test of time and be there for people to enjoy for many years to come!