June 6, 2007 | By: Carol Lea Spence
LEXINGTON, KY.

Spring has been especially cruel this year, teasing gardeners with unseasonably warm weather in March, slapping them down with a hundred-year freeze in April and now drying them out with below-normal precipitation. The question in many people's minds is, if it's this dry this early, what's the rest of the summer going to be like?

Since the first of the year, the southern part of the state has seen seven to eight fewer inches than normal precipitation. The northern counties are behind in their precipitation by two to four inches. But gardeners don’t need to know those numbers. All they have to do is run a shovel into their soil. Its cracks and dust have an August-like quality. 

Tom Priddy, meteorologist with University of Kentucky College of Agriculture, says that much of this trend has to do with a developing La Niña system in the Pacific.

“What that means for Kentucky is that it would continue the trend of dry conditions through the summer months, but it would enhance the tropical Atlantic hurricane season.”

Remembering the active hurricane season of 2005 when “we had remnants of four different tropical systems dump rain on Kentucky,” Priddy said that La Niña can be a “double-edged sword.”

“We don’t want to see that above-normal hurricane activity because of all the damage it causes to other parts of the U.S., but in the past that has helped us significantly in the state of Kentucky with La Niña in the summertime,” Priddy said. 

Let’s face it, though. When it comes to the weather, anything could occur. And in the meantime, our flower gardens are gray with dust and our newly planted vegetable beds are looking worse for wear. So what’s a gardener to do?

Perhaps Kentuckians can take a tip from other parts of the country that have learned to deal with extended periods of drought. The method, known as xeriscaping in drier western climes, is to understand the nature of the site and the region. Don’t fight the conditions. Select native plant material. It is quite likely that the current conditions have occurred before, so native plants must be at least somewhat adapted to deal with these situations.

Remember, a particular site has its own characteristics, so don’t try to go against what nature has provided. For instance, if the site gets strong afternoon sun, don’t plant thirsty shade plants. In most cases, it’s wasted energy and results in more work and more outlay of resources such as water, fertilizer – both of which mean money – and time. 

Take a discerning look at nature in the area and follow her advice. Group plants that have similar needs, putting heat-loving, drought resistant plants together in areas that receive full sun, and less hardy plants in semi-shade and nearer to a water source.

Placing plants according to sun and water requirements will only go so far in drought-proofing the home landscape. Of utmost importance is soil preparation. Making sure the soil has a healthy proportion of organic matter will improve its ability to take in and retain moisture.

Rick Durham, UK extension consumer horticulture specialist, recommends improving the soil by mixing in organic matter, but says it takes more than just shoveling some compost onto the site.

“It’s probably best not to just put compost straight on the surface of the soil,” he said. “What we find is it tends to crust, so when you do get a rain, it’s going to be harder for the water to soak through. If you use compost, it’s good to mix it into the top several inches of soil.”

What Durham does recommend putting on top of the soil is mulch, an important weapon in the battle to conserve moisture during hot spells. He recommends bark-based mulches, such as pine bark and pine bark nuggets, because they tend to break down more slowly than other types. Though he says hardwood mulch can be a good choice, it tends to decompose faster than bark-based mulches and in doing so, ties up the nitrogen in the soil.

“Basically, what it’s doing is composting right there on the soil surface. Because there’s not a balance there of carbon and nitrogen, it’s going to bring in nitrogen from the soil,” he said. “If you’re fertilizing regularly, you probably won’t notice it. But for people who don’t add very much extra nitrogen to the soil, it can tie up the nitrogen (that is already there) and make plants look stunted or light green –the symptoms of nitrogen deficiency.”

As for vegetable gardens, those thirsty plants, too, can benefit from a two- to three-inch layer of mulch.

“Straw is probably one of the preferred mulches to use in vegetable gardens. Grass clippings can be used, as well,” Durham said. “We typically stay away from some of the woody-type mulches in vegetable gardens because of that nitrogen issue.”

So what plants fit the bill for a potentially hot and dry Kentucky summer?

“Some annuals that would do really well in heat would be the Celosia or cockscomb, and the Gomphrena, which is globe amaranth,” he said. “Some of the verbenas, they’ll survive the heat. They may not flower as much when it’s hot and dry, but typically they’ll survive and then once we get rain, they’ll come back and put another round of flowering.”

Of the perennials, yarrow, Rudbeckia or black-eyed Susans, and many sedums can help the garden beat the heat. Some of the smaller asters do well also.

Finally, watering methods are very important. Rather than turning the sprinkler on in the middle of the day, when much of the water can evaporate before it soaks into the ground, Durham suggests directing the water low to the ground with soaker hoses or hand-watering devices.

For more information about drought-proofing the home landscape, contact your local Cooperative Extension office.

Contact: 

Rick Durham, 859-257-3249, Tom Priddy, 859-257-3000, ext. 245