By Dan Rahn
University of Georgia

Much of Georgia has been dry this spring, and the outlook calls for more of the same. So when you plant new container-grown trees or shrubs in your landscape, you'll have to water them often. You know that, of course. But you may not know how critical it is.

New container-grown plants may look like the older plants in your landscape, but they're not.

"In a very important way, they're still container plants for the first few weeks," said Jim Midcap, a Cooperative Extension horticulturist with the University of Georgia.

Think about how they grew before you bought them. "Container plants are grown in a mixture of bark and sand," Midcap said. "That's because those mixtures drain so well."

The bark-sand mixtures help nurseries avoid the root rot problems they might have with potting mixtures that hold moisture better. The only problem is that they also dry out fast.

Oops

"And once the mixture gets really dry, the bark is very hard to get wet again," he said.

Nurseries water their plants every day or every other day to keep the mixtures from drying out. If you don't keep that in mind when they reach your landscape, your new plants might not survive.

"If you let the root ball dry out," Midcap said, "you may think you're watering enough. But because the bark is so hard to rewet, the plant really isn't getting enough moisture to survive."

It's vital to give new trees or shrubs proper planting holes that make it easy for their roots to grow into the surrounding soil. But even if you do, he said, all of the plants' roots are still in that original potting mixture for the first four to six weeks.

Water the 'pot'

"That's what you need to water," he said. Until the roots grow into the surrounding soil, the plant still depends for moisture on the bark-sand mixture in the root ball. "Water it as if it were still in the container."

And keep watering it at least two to three times a week for the first four to six weeks. "On very warm or windy days the original bark mixture can dry out thoroughly in 24 to 48 hours, even though the backfill soil around it stays wet," Midcap said.

If you delay planting a container plant, water it several times a week, he said. Water it two to three straight times before planting to make sure the root ball is thoroughly soaked.

If the root ball still feels dry, he said, soak it in a bucket for a while just before planting. Don't plant it if the root ball is dry.

Watch the 'lid'

In a clay soil, Midcap said, keep the top of the potting mix exposed. "If you cover it with a clay soil it can seal it up so moisture can't get into that sand-bark mixture as readily," he said.

In sandy, well-draining soils, it's hard to water too much. But be careful not to overwater in clay soils and areas that don't drain well, Midcap said. Overwatering in clay soils can kill plants just as surely as not watering at all.

If a new plant starts wilting or its older, inside leaves begin yellowing, he said, don't give up on your plants.

"All you need to do is get that root ball wet again and keep it watered properly," he said. "When it dries out, the root system shuts down. And then a little later, the top begins showing stress. Give it enough water to get the root ball wet again and the plant will start regenerating absorbing roots to take up the water."

Then keep up the faithful watering. "Frequent watering of newly planted container shrubs, without overwatering, is crucial to their survival," Midcap said.

(Dan Rahn is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.)