Watering woes are not over yet

Mary Meyer did something last weekend that she's never done this late into the year. The University of Minnesota horticulture professor bought a hose -- not because it was an end-of-the-season sale, but because she needs to use it now.

"Actually, it wasn't on clearance," she said with a laugh. "It's the third hose I bought this year. I don't have an automatic irrigation system in my yard, so I need to do all the watering by hand."

After making it through a summer drought that has worn out hoses -- and the people who wrestle with them -- there's an urge to assume that because fall has arrived, we can cut back on yard maintenance. But don't be so quick to store that gear, experts say.

We've just come through the second-driest September since the state started keeping records. Figures released Thursday showed that 96 percent of the state is in moderate to extreme drought. Even though the weather is cooling off, trees, grass and plants still are stressed and need help.

"You absolutely shouldn't stop [watering] now," said garden writer Deb Brown. "If you want to have any hope of your perennials, shrubs and trees making it through a harsh winter, you need to keep watering."

Grass

Even if it appears that your grass has shut down for the season, it will keep growing -- and keep needing water -- until the ground temperature falls below 40 degrees.

In fact, those problems could be even worse, Meyer said, because the lawn will lack the reserves it needs to withstand the winter harshness.

"You don't want your lawn to go straight into winter under stress," she said.

The Extension Service also is advising homeowners not to aerate or dethatch because it will add further stress to the lawn. "Normally we recommend two fertilizings in the fall, but this year it's just one," Horgan said.

Trees

Unlike plants that wither quickly when they run out of water, drought damage in a tree might not show up for two to three years, warned Peter Moe, operations director at the Minnesota Landscape Arboretum.

But there's also a limit on how much help you still can provide them. "If the leaves have started to change color or have fallen off, the tree won't be able to take up the water," he said. "If the leaves are still green, the water will move up the tree as part of the process of photosynthesis."

However, even if all the leaves are gone, give the tree a drink. "At least the roots will be able to absorb some water," he said. And give extra water to young trees and those that are not native to the area.

Bulbs

The drought shouldn't stop you from planting fall bulbs, Meyer said. "You just have to water them really well after you plant them," she said.

Mulch

"Dry soil will freeze sooner, and the frost will move down more rapidly," he said. "Plus, with an absence of moisture, the soil has the potential to freeze deeper," although that also is a factor of the temperature.

The Climate Prediction Center recently forecast that the drought will continue into winter, which is good news for snow shovelers but not for perennials, shrubs and young trees that depend on a layer of snow as insulation. That lack of protection could be a problem even if the temperatures this winter are as mild as they were last year.

"It's often not the cold that kills the plants," Brown said. "It's the changes in temperatures -- it freezes and then it warms up. An insulating layer of snow protects the vulnerable roots from temperature variances."

Along with other experts, she's advising gardeners to mulch liberally around plants and shrubs, especially newer ones. If the forecast was wrong and we get buried in snow, at least you know that you were doing the smart thing.

"It just means that you have an extra chore to deal with in the spring" -- removing the mulch, she said. "But it's probably worth it."