@Paulpash - Ginkgo will back bud on very old wood if cut back below existing branches. But you are correct, there is a strong tendency to sprout from roots. If you remove root sprouts immediately, a few more will sprout on old bark.
This ginkgo was harvested from a weedy lot in Milwaukee back in 2010 or so. It was over 10 feet tall, and had no branches below about 5 feet tall. The seedling was at least 25, maybe 35 years old. I counted rings from another slightly smaller one harvested at the same time. Unsexed seedling from a female tree planted in the 1920's. It was dug and chopped in early spring before leaf sprouted. It takes quite a while for dormant buds under bark more than 5 years old to sprout. It was chopped in March, the first buds opened to leaves in middle of July. For that reason I suspect chopping in August (mid-summer) would not result in buds sprouting that year, but rather the following spring. Protect from extreme cold the winter after the chop.
I took possession of this one in 2016. Really have done almost nothing. As you can see, back budding was sparse, but there were at least 4 buds that became branches. A couple had sprouted from the roots, those were removed right away.
@cbroad - Most named ginkgo cultivars are propagated by grafting. Cuttings take as much as 9 months to 24 months to fully root. Because cuttings are slow, and require a ''trick or two'' all commercial nurseries propagate them by grafting. So if the ginkgo has a cultivar name it is grafted except where the advert specifically says cutting propagated. Brent at Evergreen Gardenworks does root cuttings of Chi-Chi. You can root cuttings yourself, but they will take time, my % success was zero for 20+ cuttings, taken in batches of 5 or more in 3 different years. It is not an easy species to root from cuttings. Brent is a genius and has specialized mist beds for rooting cuttings.
Grafted ginkgos, more so than maples, will heal grafting scars to the point where they are no longer visible. Especially for normal size and semi-dwarf cultivars the graft union will disappear entirely with time. This bodes well for using grafted female ginkgo clones as bonsai. Some dwarf and miniature ginkgo the growth rates will be different enough that the scion will become obvious as the understock will grow faster than the scion. But grafted trees are pretty much the only source for named cultivars.
I might have the exact measurement wrong, but I think I'm pretty close to accurate on the measurements below;
Semi-Dwarf trees grow less than 10 inches per year
Dwarf trees grow less than 6 inches per year
Miniature trees grow less than 2 inches per year.
So there is nothing wrong with using a grafted ginkgo for bonsai.
Female ginkgo.
I had the opportunity to eat boiled ginkgo nuts, as is and used in soups, stuffing for chicken, and in a gravy for beef. They are delicious. This got me fired up about raising a ginkgo for nuts, and or using a female ginkgo as bonsai. Imagine one inch diameter nuts hanging in a shohin size ginkgo. I was disappointed when I realized that like the North American hickories, Ginkgo need to be over 30 years old from seed before they begin flowering. As bonsai, even if you have a tree of sufficient age, they tend to need to be fairly large trees before they will flower. You ''never'' see photos of ginkgo with seed hanging. Even from China, where commercial ginkgo seed production is common. Two reasons, both the Chinese and Japanese consider the odor of ripening fruit obnoxious, which is really only a problem when you have a tree with thousands of nuts hanging. The odor from just a few should not be an issue. Second it is very likely that female tree rarely fruit when container grown and pruned to bonsai size, even larger bonsai sizes don't seem to be large enough for nut production.
So I am not trying to be a ''Debbie Downer'' but it is unlikely you will get a ginkgo to fruit and produce nuts in a container. But DAMN IT, I'm still trying. Thirty years is a long time to wait for unsexed seedlings, but I intend to live long enough.
There is always the chance of finding a precocious seedling that will bloom at an age less than 30 years. Named varieties of other species of nut trees were selected for this trait. So who knows, with enough seedlings and grafted female trees, someone might get lucky.
