HOUSTON — The co-owner of a landscaping company here called Garden Guy turned down a job in October by sending an e-mail to a man who had requested an estimate for work on his yard:

“I am appreciative of your time on the phone today and glad you contacted us,” Sabrina Farber wrote. “I need to tell you that we cannot meet with you because we choose not to work with homosexuals. Best of luck in finding someone else to fill your landscaping needs. All the best.”

Floored, the recipient of the e-mail, Michael Lord, and his partner forwarded the message to dozens of friends. Within days, the e-mail had spread across the Internet to bloggers, the homosexual press, and online gardening forums from Seattle to Washington, D.C.

Ms. Farber and her husband, Todd, who’ve owned the landscaping company since 1991, were bombarded with profane phone calls and e-mails. Their online forum flooded with outraged posts.

“It blackens my mind to think that an alternative version of the KKK is alive & kicking in the USA,” read one of the milder comments.

The Farbers, declining interviews, released a statement saying they “do not hate homosexuals” and “did not refuse service with malicious intent. … We meant to uphold our right as small business owners to choose” their clients. “We are humbly sorry for the hurt that it has caused.”

Mr. Lord and his partner, Gary Lackey, also declined to be interviewed.

The episode was a jolt to many in Houston, where gays and lesbians have enjoyed increasing acceptance over the years. Despite the city’s conservative reputation, there’s been a significant shift in support of gay rights here, said JackValinski, executive director of Pride Houston, a gay-rights group.

“The e-mail was an aberration. People may want to discriminate, but they’re not blatant and public about it like they were before.”

Gay and lesbian activist Carol Wyatt said she’s “not surprised by homophobia but that this woman thought it was socially acceptable to write about it in an e-mail. We’ve come a long way in Houston in terms of tolerance and acceptance. For this to bubble up is embarrassing for a lot of people who care about this city.”

There have been no threats of legal action, and both sides seem content to let the matter die. But Mr. Valinski said activists may push for an anti-discrimination ordinance that prevents businesses from rejecting customers based on sexual orientation.

The Farbers are clear about their convictions in a “Learn About Garden Guy” page of their Web site: www.garden-guy.com. “The God-ordained institution of marriage is under attack in courts across the nation, and your help is needed,” reads a tagline above a link to nogaymarriage.com.

The president of the Tupelo, Miss.-based American Family Association, Tim Wildmon, defends the Farbers.

“It shouldn’t come as a shock when a guy who takes his faith seriously says ‘I can’t support this,”‘ Mr. Wildmon said. “He doesn’t need to be persecuted for his actions.”

A few posters on the now-defunct Garden Guy forum agreed.