New Shrubs/Trees – Watering

arborvitae: how often to water new trees

Q: I planted 5 Green Giant arborvitaes in my backyard along a fence to provide a hedge in the future. The space gets full sun. We mixed in soil conditioner with the red clay when planting them. The trees are six feet tall and seven feet apart. We have looped several soaker hoses around the trees in an oval pattern. How often and for how long do I need to water them?

A: As the disappointed owner of three arborvitae shrubs that I failed to water properly, I appreciate your concern.

The right answer is “Water enough to keep the rootball constantly moist (not soggy) for the next six months.”

That’s easy to say but hard to accomplish.

Here’s what I’d do: for the first month give each plant a dousing of 10 gallons of water every five days in the absence of rainfall. Pour the water slowly and directly at the base of each plant so the rootball is thoroughly wet.

Roots don’t expand very quickly, so the plant depends on the rootball having the water it needs…and I don’t think a soaker hose can accomplish that.

That said, the soaker hoses are a good idea because they keep the surrounding soil moist so water from the rootball doesn’t quickly migrate outward after you pour it on. To that end, run the soaker hose an hour every third day so the soil around the rootball is kept moist but not soggy.

As summer cools into fall, the plants won’t need quite as much water….but a hot, dry spell in October can change things in a hurry. Never let them go more than ten days without direct rootball watering from now (August) until December.

A product that really helps with this is a TreeGator. The 20 gallon size can be filled once per week. Otherwise, use a 5 gallon bucket to deliver water. I don’t recommend a hose because it’s so hard to know when it has delivered the right amount of water. If mosquitoes are biting when you’re watering, the trees will be lucky to get 5 gallons of water.

Remember, it will take at least six months until they can get along without maintenance.

Yes, this looks like a pain in the patoot….but you spent good bucks for your 5 plants and there’s no sense wasting it.

Use the reminder function on your smartphone to tell you to water each week.

You can fertilize next spring. They will really take off after a year of establishment.

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