Winter Watering for Evergreen Trees in Ohio

Most of the evergreen damage I see in March on Central Ohio properties didn’t happen in February cold snaps. It happened the previous November and December when the trees went into winter thirsty and stayed that way. I’ve been working on landscape and tree care across Pickaway, Franklin, and Fairfield counties for more than ten years, and winter watering is probably the most underappreciated thing a homeowner can do for an evergreen tree or shrub in this climate.

Lawn Harmony Landscaping handles evergreen care as part of regular property maintenance. This is what I do on my own property and on the client properties where we manage trees and shrubs through the winter.

Do evergreens really need to be watered in winter in Ohio?

Yes, and the most important watering window in Central Ohio is mid-October through mid-December, before the ground freezes solid. Evergreens keep their needles or scale-like leaves all winter, and they lose moisture through those leaves every day there’s wind or sun. If the root zone is dry going into winter and stays dry through a mild stretch in January or February, the tree can’t replace what’s lost above ground, and the needles brown.

The damage is called winter desiccation, and it shows up as brown, dry, dead foliage on the windward side of the tree, typically the southwest or west exposure in our climate. By the time you see it in March, the damage is done. The tree may recover from light desiccation, but heavy damage kills branches or the whole plant.

Per OSU Extension horticulture guidance, evergreens in our zone benefit from supplemental watering anytime the soil at root depth is dry and the ground is not frozen, regardless of the calendar month.

On a Bexley property I service, the homeowner has three boxwood balls flanking the front walk that have struggled every spring for years. Last November we ran a soil moisture probe and found the root zone was bone dry six inches down despite normal rainfall the previous month. Two deep waterings, two weeks apart, before Thanksgiving, and the boxwoods came out of last winter looking better than they had in four years.

When should I do my last deep watering of the year?

The target is to get one deep watering in within about two weeks before your average first hard freeze, which for Central Ohio is usually the second or third week of November. That gives the water time to soak deep into the root zone and reach equilibrium before the surface freezes.

A second watering in early December is worth doing if November has been dry and temperatures are still mild enough that the ground isn’t frozen. I usually pick a day forecast to stay above 40 degrees for at least 48 hours, run the hoses in the morning, and let the water soak in through the warmest part of the day.

Once the ground freezes solid at root depth, watering stops being useful because the water can’t get to the roots. But Central Ohio winters often include mild stretches in January and February when the top several inches thaw. Those are bonus watering opportunities if you can take them. Even one extra deep watering during a January thaw can make a real difference for stressed evergreens.

How much water does an evergreen need?

The rule of thumb I use is 10 gallons per inch of trunk diameter for a tree, applied slowly over the root zone, not in a single splash. For shrubs, 5 gallons per foot of height for the first watering of the late fall and a bit less for follow-ups.

A 4-inch caliper Norway spruce gets about 40 gallons in a single late-fall watering. A 6-foot arborvitae gets about 30 gallons. A foundation row of three 3-foot boxwoods gets about 15 gallons each.

That’s more water than people usually picture. A standard garden hose at moderate pressure delivers roughly 5 to 8 gallons per minute, so a 40-gallon watering takes 5 to 8 minutes per tree at the base. If you’re using a soaker hose or a slow drip, plan on 30 to 60 minutes per tree because the water needs to soak in rather than run off.

On a Lancaster property where we manage a row of twelve emerald green arborvitae along a property line, I do one deep watering with a 100-foot soaker hose in mid-November and let it run for about three hours total. The hose moves down the row over the course of the morning, soaking each tree’s root zone in turn. Same setup repeats in early December if the weather cooperates.

Where should the water actually go?

Not at the trunk. The water needs to reach the feeder roots, which are in the outer two-thirds of the root zone, generally extending from about a third of the way from the trunk out to slightly beyond the drip line of the canopy.

Set your hose, soaker, or sprinkler so the bulk of the water lands in that ring, not right against the bark. Watering directly against the trunk wastes water on roots that aren’t actively absorbing and can encourage trunk rot on some species.

For young trees less than three years old in the ground, focus most of the water within a 24-inch radius of the trunk because their root systems haven’t spread far yet. For established trees, work the full canopy drip line.

What’s the right way to measure if my evergreens need water?

The best tool is a long screwdriver or a dedicated soil moisture probe. Push it into the soil at root depth, somewhere in the active root zone, not right at the trunk. If it goes in easily for the first 8 to 10 inches, soil moisture is reasonable. If it stops at 2 or 3 inches against resistance, the soil is dry and the tree needs water.

For homeowners who’d rather not poke around with a screwdriver, a quick visual check works. Look for needles that are slightly dull or losing their luster compared to the deeper green of a healthy specimen. On arborvitae and yews, look for foliage tips that are slightly curled or dry-feeling between your fingers. None of these signs are foolproof, but combined with rainfall totals from the previous month, they give you a decent read.

The Ohio Department of Natural Resources maintains drought monitor data that’s worth a glance in mid-November. If the previous 60 days have been classified as abnormally dry or worse, your evergreens are nearly certainly underwatered and you should plan a deep fall watering even if your yard looks fine.

Which species need winter watering the most?

In rough order of how prone they are to winter desiccation in Central Ohio:

• Arborvitae (very prone, especially exposed plantings)
• Boxwood (very prone, especially on south or west exposure)
• Yew (moderately prone)
• Holly (moderately prone, evergreen species)
• Norway spruce and Colorado blue spruce (somewhat prone when young, less so once mature)
• White pine (moderately prone)
• Eastern red cedar / juniper (least prone but still benefits from late fall watering)

Newly planted evergreens of any species are at the highest risk because the root system hasn’t expanded into the surrounding soil yet. Any evergreen planted within the last three growing seasons should get a deep late-fall watering as a default, no exceptions, unless the property is on automatic irrigation that’s been running through the fall.

What if my evergreens are on an irrigation system?

Most residential irrigation in Central Ohio is winterized and blown out by mid-October, which means automatic watering stops well before the critical late-fall window. If your system is winterized and your evergreens haven’t had significant rain in the last two weeks, plan a hand watering even though the system is offline.

A few clients in Upper Arlington and Bexley run their drip lines into November on a manual schedule before winterizing. That’s a good approach if you have the discipline to remember the drain-down before the first hard freeze. If you don’t, blow it out earlier and hand-water once or twice.

What about mulch?

A 2 to 3 inch ring of hardwood mulch around evergreens does two important things for winter survival. It moderates soil temperature so the freeze-thaw cycles aren’t as extreme, and it slows evaporation from the root zone.

Refresh or top off mulch in late October or early November on any evergreens that look thin or have bare soil showing in the ring. Don’t pile mulch against the trunk. Pull it back an inch or two from the bark to prevent rodent damage and rot.

On a Pickerington property where we manage a foundation row of green giant arborvitae, a 3-inch mulch ring extended to the drip line cut the supplemental watering need by about a third compared to a similar planting next door with no mulch. Same trees, same exposure, very different soil moisture readings into December.

Common winter watering mistakes

• Watering once at a trickle for 30 minutes and assuming it was enough (it wasn’t)
• Watering only at the trunk where the roots can’t absorb
• Stopping all watering on October 15 because the calendar says fall is over
• Skipping young evergreens because they look fine in November
• Watering after the ground is already frozen solid (water just runs off)
• Ignoring south- and west-exposure plantings, which need the most water

Want help with evergreen care and winter property prep?

Lawn Harmony Landscaping handles tree and shrub care, mulching, and pre-winter property walks across Central Ohio. We’re owner-operated, locally based in Circleville, licensed and insured, with a 5.0-star Google rating.

For a free written quote, call 614-425-9789 or email Lawnharmonyohio@gmail.com. You can get a fast residential estimate at quick-mow-quote.emergent.host. Commercial properties can request a walkthrough at /quote/commercial.

For more on protecting trees and shrubs this winter, read our companion pieces on anti-desiccant spray for Ohio evergreens and the mid-November property walk for Ohio owners.

Service area: Circleville, Columbus, Grove City, Bexley, Upper Arlington, Pickerington, Canal Winchester, Groveport, Lancaster, Baltimore, Chillicothe, Washington Court House, and Jeffersonville.