Ann Million is thrilled about her daughter's change of heart for her wedding plans. The vows are still on for October, but they'll be exchanged in a church and not the family's backyard in Crestwood, as planned.

"I'm so glad she switched because this is the worst year my garden has ever had, and my yard was the worst it's ever been since we moved in our house 31 years ago," she said.

She said the pre-emergent her lawn service applied in spring took care of the crabgrass, but the outbreak of nutsedge this summer and toasted grass left her at wit's end.

Treating the sedge "killed the surrounding grass wherever we sprayed it," Million said. "The brown patches might have been fungal activity, too, but I think we applied it in too hot weather and that killed the grass."

The summer's heat wave not only left wedding planners perspiring, it wrecked plenty of lawns as well.

Though daily highs had their typical run of the 90s, the average overnight low temperature is what wreaked havoc with turf grasses. The overnight lows averaged the warmest since the National Weather Service began keeping official records in 1870.

"That's the single-handed worst thing that can happen to grass," turf specialist Glennon Kraemer said. "As the name implies, cool-season grass can't handle 85-degree nights like we had through July and August. So that's what put the stress on grass, to allow weeds, disease and insects to move in."

Kraemer said homeowners often unwittingly contribute to the problem by not watering deeply enough and mowing too short, in effect encouraging shallow roots.

Nutsedge, or nutgrass, has been particularly prolific this season, reflective of the increased number of inquiries received by the Horticulture Answer Service at the Missouri Botanical Garden.

Chip Tynan, who heads the service, said: "Last year, I don't think the nutsedge was as much of a problem; it certainly was present, but last summer was cooler. This summer, it's been much, much warmer. And the combination of the abundant moisture during those times and the heat, it's just been perfect growing conditions for nutsedge."

The grasslike plant tends to be bright green and is noticeable because it grows much faster than the surrounding grass. The plant reproduces by seed and underground tubers, or nutlets.

Often, those nutlets are left behind when the plant is pulled, promising even more sedge.

Ron Egan, crew manager for Dunn Lawn Service in north St. Louis County, said: "Nutsedge has been insane this year. Even with the yards we treat, we've had to spot-spray quite a bit more than usual."

Kraemer added: "Sedge doesn't wake up until Mother Nature wakes her up. And when she did, she kept going. We had the fourth-warmest summer in history, and what made it worse was how abnormally cool it was last year."

This summer's daily average temperature was 81.7 degrees, compared with last year's 76.6. The average nighttime low this year was 72.6 degrees, more than 4 degrees warmer than a typical summer. "Grass doesn't forget that," Kraemer said.

Several brief rains only worsened the problem because "the water acts as a magnifying glass and burns up grass tissue," he said.

Kraemer said many residents were lulled into a false sense last year that their yards were in good shape after the mild summer. "Last year at this time, we were kind of loafing. We take a year off, and that compounds the problem because we felt safe and did nothing. It's what we do in the fall that leads to the health of the grass in the coming year."

Kraemer stressed core aeration and reseeding at this time of the season to get lawns back in good form.

Egan recommends that homeowners water only once a week. "A lot of people water every day, and then the roots don't go deep enough that when we hit that heat and drought, it kills them," he said. He recommends watering three hours once a week, "and every one I get to do that, their yard makes it."

He said as the weather warms up, the height of the service's mowers is adjusted from 3¼ inches to 4½ inches. "The higher you cut, it helps most of the time when the heat hits," he said. "It holds in the moisture in the morning, and the sun doesn't seem to stress it as quickly."

He suggested that homeowners use a water timer to assure their lawns get the proper irrigation.

Million said the logistics of holding a garden wedding prompted her daughter to switch plans actually before the garden and yard had gone south. "But this garden isn't going to look like much on Oct. 22, so it's a good thing, I think," she said.