When to Prune Ginkgo Trees in the UK

The ginkgo, Ginkgo biloba, is the oldest thing I work on by a margin I can’t really get my head around. Fossil leaves more than 200 million years old are almost identical to the ones that blow across London pavements every November, and the tree has no living relatives left at all. Most people know it as the maidenhair tree, after the fan-shaped leaves that look like the fronds of a maidenhair fern. It came to Britain in the eighteenth century, and one of the very first, planted in 1762, still stands at Kew as one of the garden’s “Old Lions”. Like the monkey puzzle, it’s a living fossil, though this one has ended up as a London street tree.

As a certified arborist in London working for London Tree Surgeons, I see more ginkgos every year. Councils plant them along roads because they put up with pollution, poor soil and nearly every pest going, and there’s a fine mature one beside the old brick wall in Broomfield Park, Palmers Green, which is the tree in the photos on this page. Here’s the awkward thing for a pruning guide, though. A ginkgo hardly needs pruning. So this article is as much about when to leave the saw in the van as when to pick it up.

Best Time to Prune Ginkgo Trees in the UK

If a ginkgo does need live wood taken off, the best time is late winter, in January or February, while the tree is fully dormant and before the buds begin to swell.

Why late winter?

1. You can see what you’re doing: With the leaves down, the whole framework is on show, the long main branches and all the stubby little side spurs that carry the foliage. It’s far easier to pick the right cut on a bare tree than through a wall of green.
2. The tree is resting: Nothing is being asked of it in January. A cut made now is followed within a few weeks by the spring growth that starts to seal it, so the wound isn’t left sitting open for half a year.
3. You’re ahead of the birds: The main nesting season runs from March to August. Get the work done in winter and that whole question never comes up.

Arborist’s Tip: Dead, broken or storm-damaged branches are the exception to all of this. They can come out in any month, so don’t wait for winter if something is hanging over the path.

Worst Time to Prune Ginkgo Trees in the UK

The worst time to prune a ginkgo is spring, from about March to May, as the buds break.
A ginkgo comes into leaf in April and May, and everything it stored over the winter goes into that first flush. Cut it then and you’re throwing away growth the tree has only just paid for, on a species that is slow to make it back. You’re also working in the thick of the nesting season. Under the Wildlife and Countryside Act 1981 it’s an offence to intentionally damage or destroy an active bird’s nest, so anything done between March and August needs a proper check first.

Autumn is the other one to skip

People plant a ginkgo for about a fortnight of the year. Some time in late October or November the whole crown turns a clear butter yellow, and then, often after the first sharp frost, it drops the lot almost overnight and leaves a yellow carpet underneath. Pruning in September means cutting off the show you’ve waited all year for. It also leaves fresh wounds sitting through the wettest months with no growth to close them.
Arborist’s Tip: Whatever the month, don’t prune in a hard frost. Frozen wood tears instead of cutting cleanly, and a ragged wound takes far longer to seal.

How to Prune a Ginkgo Tree

The RHS entry for Ginkgo biloba has three words under pruning, “No pruning required”, and after years of working on them I’ve nothing much to add. A ginkgo builds its own shape. It starts out narrow and a bit gawky, then broadens and loosens with age into something that looks different on every tree. Nearly all the pruning I do on them is for the benefit of the people living underneath. Use clean, sharp, sterilised tools whenever you do cut.

Formative Pruning (Young Trees)

A young ginkgo is an awkward teenager. It’s all elbows, with a few long branches sticking out at odd angles and big gaps between them, and the temptation is to tidy it up. Mostly, don’t.

• Keep one leader: If a second upright shoot starts competing with the main stem, take it out while it’s still thin enough for secateurs. That’s the one cut on a young ginkgo that really matters.
• Leave the spurs alone: Those short, knobbly stubs along the branches look like dead twigs in winter. They aren’t. They’re the spur shoots that carry the leaves, and on a female tree the fruit, and they can stay productive for decades.
• Don’t tip the long shoots: Shortening the branches to make the tree “bushier” doesn’t work on a ginkgo. The gaps fill in on their own, given time.

Maintenance Pruning (Mature Trees)

On an established tree the list is short enough to do from memory.

• The three D’s: Take out anything dead, diseased or damaged. On a healthy ginkgo there’s rarely much of it.
• Crossing branches: Remove a limb that’s rubbing against another before the two wear a wound into each other.

Crown Lifting (Paths, Drives and Pavements)

This is the job I’m asked for most. As the lower branches of a ginkgo lengthen they start to hang, and sooner or later they’re brushing heads on a footpath or scraping the roof of a van. A crown lift takes those lowest limbs back to the trunk, or to a decent side branch, and gives you clearance without touching the shape of the crown above. It’s a late winter job like any other live cut. If yours has reached that stage, our tree pruning team can lift it properly and leave it looking as though nothing was done.

Reducing a Ginkgo That’s Too Big

I’ll give the ginkgo this, it is very hard to kill. Six of them were growing close to the centre of the atomic blast at Hiroshima in 1945, and all six came back into leaf and are still alive today. So yes, a ginkgo will re-shoot if you cut it hard. The trouble is what it re-shoots with. Top one and you get a fistful of stiff, bolt-upright shoots from each cut, on a tree slow enough that you’ll be looking at them for the next ten years. I’ve seen a few done that way and none of them ever looked right again. Where a ginkgo has really outgrown its space, a qualified arborist can shorten selected branches back to natural growth points, in line with BS3998, and keep the outline. For a small garden the better answer comes earlier. There are narrow, upright forms and proper dwarf varieties such as ‘Mariken’, and choosing one of those saves all the bother.

Common Diseases and Pests of Ginkgo Trees in the UK

This is the shortest disease section I’ve written for any tree. The RHS lists the ginkgo as generally pest-free, and in my experience very little that troubles other London trees shows any interest in it. What follows is the little there is.

Honey Fungus (Armillaria spp.)

The RHS says a ginkgo may be susceptible to honey fungus, and then adds the word “rarely”. I’ve never had to take one down because of it. The signs are the same as on any other tree, a crown that thins from the bottom up, and a white sheet of fungus with a strong mushroom smell under the bark at the base. There’s no treatment. If you find it, get someone out to look before you plant anything else nearby.

Slow Establishment and Drought Scorch

Most of the “sick” ginkgos I’m called to are young and simply sulking. A newly planted one can sit for three or four years doing next to nothing above ground, and in a dry summer the leaf edges go brown and crisp. That’s thirst, and there’s no disease involved. A deep soak every week or so through dry weather and a mulch over the roots will do it more good than anything else. Once it gets going, it tends to look after itself for the next few centuries.

The Fruit on Female Trees

It isn’t a disease, but it’s the one real complaint anyone has about a ginkgo. The trees are either male or female, and a mature female sets round, plum-like seeds that ripen yellow and fall in autumn. The Broomfield Park tree is a female, and you can see the green fruit among the leaves in the close-up above. As the flesh rots it gives off a smell that Kew describes, kindly, as rancid butter. The flesh can irritate bare skin, and the RHS notes the seeds are toxic to pets, so wear gloves and keep the dog away while you clear them. Pruning won’t stop a female fruiting, and you often can’t tell which you’ve got until the tree is twenty years old or more. If the smell is more than you can live with, the lasting answer is to replace the tree, and our tree planting team can source a named male variety that will never fruit.

6 FAQs About Pruning a Ginkgo Tree

When is the best time to prune a ginkgo tree in the UK?

Late winter, in January or February, while the tree is fully dormant and before the buds start to swell. With the leaves off you can see the whole framework, and the cuts are made just ahead of the spring growth that seals them. Dead or broken branches are the exception and can come out in any month. Most mature ginkgos never need more than that.

Can I keep a ginkgo tree small by pruning?

Not really, and I’d talk you out of trying. A ginkgo will re-shoot after hard cutting, but it answers with clumps of stiff, upright shoots that spoil its shape, and it grows slowly enough that you’ll be looking at the result for years. A light reduction back to natural growth points is possible on a tree that has outgrown its spot. If what you want is a small ginkgo, the honest answer is to plant a dwarf or narrow variety in the first place.

Is a ginkgo the same as a maidenhair tree?

Yes. Ginkgo biloba is the botanical name and maidenhair tree is the traditional English one, given because the fan-shaped leaves look like the fronds of a maidenhair fern. You’ll also hear it called the fossil tree, since leaves found in rocks more than 200 million years old are almost identical to the ones on the tree today. It has no close living relatives at all.

Why does my ginkgo tree smell, and will pruning stop it?

If it smells, it’s a female. Ginkgos are either male or female, and in autumn a mature female drops fleshy, yellowish seeds that give off a stink of rancid butter as they rot. Pruning won’t prevent it, because the seeds form on short spurs all through the crown and you’d have to strip the tree bare. Clearing the fallen seeds promptly, with gloves on, is the practical fix. Replacing the tree with a male one is the permanent fix.

How fast do ginkgo trees grow in the UK?

Slowly, especially at the start. A newly planted ginkgo can sit almost still for several years while it roots in, and only then does it settle into a steady pace. The RHS gives it 20 to 50 years to reach full height, which can be well over 12 metres. That slow growth is one reason a ginkgo so rarely needs pruning. It’s also why any mistake with a saw takes so long to grow out.

Do I need permission to prune a ginkgo tree?

Possibly. If a Tree Preservation Order (TPO) applies you need the council’s written consent before any work, and in a conservation area you must give six weeks’ notice under a Section 211 notification. Plenty of London’s older ginkgos stand in exactly those places. Check the tree’s status before anyone cuts anything. Our guide to TPOs and protected trees in London explains both routes.

Article written by: Mike Fielding (Certified UK Arborist – Level 4 Diploma in Arboriculture)

Article source: When To Prune Ginkgo Trees UK