Many gardeners spend a lot of time watering their shrubs and edible crops, often forgetting about the needs of their landscape trees.
Lots of trees do just fine with receiving moisture from rainfall alone, but it usually isn’t optimal – especially if it’s a ginkgo.
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Ginkgos have a lot going for them: ornamental appeal in the landscape, a decent resistance to pests and disease, and a history of existence that spans back over 200 million years.
You can learn more about the history of these trees and how best to cultivate them in our guide to growing Ginkgo biloba.
These aren’t the thirstiest of plants, as they do tolerate some drought once established.
However, optimal irrigation is definitely one difference between a good ginkgo and a great one. But how to water it the right way? That’s what we’ll cover in this guide.
Here’s what we’ll be talking about:
The Importance of Proper Irrigation
It goes without saying that plants need enough water, but it’s fun to know why.
Chemically, the vast majority of a plant is water. So as you can imagine, moisture is vital for all kinds of plant processes.
At the cellular level, cells need water to elongate, divide, and sustain themselves.
Plus, it is a key ingredient in photosynthesis, the energy-producing process that plants use to make glucose and oxygen from carbon dioxide, water, and sunlight.
After roots absorb moisture and nutrients from the soil, nutrients travel via transpiration up to the shoots. Without water, this nutrient transport can’t happen.
In addition, plants suffering from too much sun and high temperatures use water at an increased rate to stay cool.
Without adequate moisture, overheated specimens develop scorched, crispy leaves, and may eventually die.
Plant cells contain large, fluid-filled sacs which contain water and other liquids. When full, these vacuoles provide structural stability, kinda like inflatable building blocks.
It’s not like the trunk itself will sag and flop over without enough water, but the foliage definitely will.
And a tree with droopy leaves – that aren’t supposed to be, anyway – is definitely unattractive.
When to Water
This guide will discuss watering specimens that you’ve already got growing in your landscape.
If you’ve got seedlings or transplants that aren’t established yet, you’ll need to keep the soil around the roots evenly moist. At all times. You want the soil to feel like a well-wrung-out sponge, not waterlogged and not dry, either.
You’ll know that your tree is established once it starts putting out new growth at a consistent, steady rate – comparing pictures or your mental snapshots can help you identify when this occurs.
For established specimens, a more moderate amount of water is ideal.
These trees do best when they receive irrigation whenever the top three to six inches of the soil is dry. This keeps the soil mostly moist while eliminating the risk of oversaturating it.
The best time of day for watering is in the early morning, before the sun has significantly risen in the sky.
This supplies the trees with enough moisture to make it through the day’s heat, allows for the water to percolate through the soil and reach the roots before it evaporates, and gives any surface moisture time to evaporate before nightfall.
Why is nighttime moisture less-than-awesome? Well, damp surfaces are prime spots for harmful microorganisms like fungi to grow and develop.
Add the nighttime humidity of a summer night – I’m looking at you, Missouri – and you could end up with a gnarly disease-causing pathogen or two.
Be sure to pay attention to your local weather forecasts and coordinate your waterings accordingly. No use irrigating your landscape when a rainstorm is an hour away, y’know?
Cease watering by your area’s first fall frost date or whenever air and soil temperatures are consistently below 40°F, whichever occurs first.
After the final frost of spring or whenever temperatures are consistently above 40°F again, resume your watering.
How to Water
A ginkgo has a much larger root system than your typical herbaceous perennials do – its roots can span two to three times the width of its already wide canopy!
You should water the roots from at least six inches away from the trunk all the way out to the “drip line” of the tree, i.e. the widest-spanning ends of the branches. Or even several feet beyond the drip line, if you can.
To irrigate your tree optimally, you’ve got a couple of options.
First, you can use a long soaker hose to cover the area of soil that you’ll be irrigating, setting it in a spiral pattern. Once you turn the hose on, it’ll provide a pretty even coverage of water over your intended area.
You’ll need to leave the hose going until the moisture has percolated down at least 12 inches – you can check this with a soil moisture meter or any long, thin bit of metal such as a tent stake. This may take an hour or longer, if you have a large specimen and the ground is very dry.
Alternatively, you can use a hose and irrigate your trees by hand, or perhaps leave it in place on the ground and move it around as needed.
A slow, even flow of water is much better than blasting the ground and potentially disrupting the soil surface, so be gentle with your irrigation. A sprinkler attachment where you can switch to the “shower” or “soaker” setting may be helpful for you, too.
Deep and infrequent watering is much better than providing shallow-soaking sips more often.
Grow That Ginkgo With H2O
Now that you know how to irrigate your ginkgo trees correctly, you can maintain their lush and vibrant growth.
Thankfully, their drought tolerance makes them pretty forgiving of forgetful waterers.
Still have questions, or something you’d like to say? Let us know in the comments section below!
And for more information about growing ginkgo trees, check out these guides next:
