Watering is the lifeblood for new trees and plants

July 01, 2008

Plants need water. It's a basic fact, yet many gardeners are unsure as to how much and how often to water trees and shrubs. So, let's cover some basics.

New plants need more water to get established. Whether you're planting a shrub or tree, you want to encourage roots to grow deeply. Slow, deep watering is the ticket to healthy trees and shrubs.

Use one of several methods for a deep watering. Stretch a garden hose to the plant's base, placing the nozzle a few inches from the trunk. Turn the water on so that the hose delivers a slow trickle.

The time you water depends on the size of the plant. Water a shrub for about 30 minutes. Water a tree for an hour. Again, the idea is to soak the entire root ball to encourage the roots to grow deep and strong.


You can also use a soaker hose. Made of recycled tires, soaker hoses seep water slowly. Wrap one loosely a few times around the base of a tree or shrub (away from the trunk). Because they drip water more slowly, double or triple the watering times above or follow the manufacturer's recommendations.

Tree Gators make watering new trees easier. A watering bag that wraps around the tree, Tree Gators have tiny holes that let 15 to 25 gallons of water trickle slowly into the root ball. Easy to fill with a hose, Tree Gators are available online and at garden centers.

You can make your own slow-watering device with two 5-gallon buckets. Use a nail to make small holes in the bottom of one bucket. Place it at the base of a tree. Fill it with water from the other bucket and let it slowly water your plant. Move the bucket around the tree as you refill it to water the entire root ball.

Avoid two common ways to water: a sprinkler and a dumped bucket of water. Sprinklers water lawns well, but don't water deeply enough to be helpful to a tree or shrub. Water dumped from a bucket runs off quickly and doesn't soak in.

How often should you water? New trees and shrubs should be watered twice a week, whether it rains or not. Most rains we get don't deliver enough water to saturate a root ball or are "gully washers" that dump rain too quickly to be absorbed.

Newly planted trees and shrubs need to be watered for a full year to establish well. I know that's a lot of work. But good watering equals good health. It is the single most important factor in determining whether a plant survives and thrives. It's also the best way to protect your investment.

You get the winter months off, but you need to keep up your watering schedule for an entire year. Whether you plant a tree or shrub in the spring or fall, water it through Thanksgiving. Then, start watering again in March.

Some locations require more water. Trees and shrubs dry out faster in windy spots or on slopes, so they need more water. Overhangs block rain, so plants tucked under them need extra water, too. Keep a good gardener eye on these special needs plants.

You can cut down on the amount of watering you need to do by planting in the spring or fall. Plants planted then need less water to become established. A 2- to 4-inch layer of mulch spread over the root zone also helps plants retain water.

Once trees and shrubs are established, they generally don't need to be watered. Mother Nature takes care of that for you. The only exceptions are in a drought or in a dry, windy winter when all plants appreciate extra water.

If it hasn't rained for several weeks, established trees and shrubs benefit from a monthly watering. Your goal is to soak the feeder roots which run about a foot deep and as wide as the plant. Use the slow watering method you prefer and move the hose or bucket to drench the entire root area.

Watering well gives new shrubs and trees their best start. It builds strong, healthy roots and lays the foundation for a lifetime of good health.

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