SUN CITY -- The weeds that poke through the rock lawns here were more than just a nuisance Saturday morning.

Those weeds, removed by hundreds of bare and glove-covered hands, were a way for more than 200 young men and women from Southwest County Mormon churches to give back to their community.

At a home in the 25000 block of Sun City Boulevard, Colby Griffiths was piling weeds on a shirt, which he dragged along behind him as he made his way across Bill and Harriet Mosteller's rock lawn.

Bill Mosteller -- in a wheelchair that was being pushed by one of the Mormon youth, 16-year-old Mike Carle -- thanked Griffiths, a 29-year-old host parent who lives in Winchester, for his service.

"Every time we help someone it brings us happiness," Griffiths said. "We enjoy it. That's why I'm so glad to be here; we get to give back."

"This is phenomenal," Mosteller replied, looking at the beehive of activity on his lawn. "Bless your hearts."

After meeting at the Church of Jesus Christ of Latter-day Saints on Bradley Road here, the youths, divided into workteams of 6 or 12, fanned out across the city, visiting 40 homes to help seniors with household chores, including weed-pulling, window-washing and minor repairs.

Each year, the area's Mormon youths gather for a weekend conference, said Lesa Sobek, of Menifee, one of the host parents and the church's public relations officer.

Friday, a day off from school for many of the teens, featured team-building exercises in the morning and a carnival with games and prizes at night. On Saturday night, a dance was scheduled. Sunday is the day for worship and spoken testimonials, said Sobek's husband, Jim, who was cleaning up the eastern edge of the lawn.

Saturday morning and afternoon were reserved for charity. In past years, the youths -- ages 14-18 -- have helped stage a Special Olympics event and repair a Temecula home for women and children, Lisa Sobek said.

This year, the church partnered with Sun City Concern, a nonprofit organization that stages bingo events, offers free in-home visits for seniors and operates a call center that checks in with seniors each morning.

Lee Tankesley, president of the Concern board, said Saturday morning marked the first time the group has teamed with the church, which sent workcrews to the homes of 40 seniors who quickly signed up for the free housekeeping.

The vast majority of the homes in this planned community of almost 20,000 residents feature rock lawns instead of grass lawns, a design choice made by the developer to lessen the home maintenance workload for seniors, Tankesley said.

While these lawns don't need mowing, weeds are still a problem.

Sun CIty Concern helps when it can, giving out free referrals to local landscape companies and handymen.

"It's one of the services we provide. Some of the seniors are not as self-sufficient and there are a lot that can't provide for themselves," he said.

Debbie Yokshas, of Lake Elsinore, 17, got a chance to talk with Bill Mosteller during a weed-pulling break.

She said the conversation, which included a story of Mosteller's battle with polio in the early 1950s, was one of the highlights of her weekend.

"Every year we go and do service," Debbie said. "Sometimes it's hard to get kids to do it but once you're doing it, you always enjoy it."

Mosteller, a retired chef who has lived in Sun City for 21 years, said it's easy to hear about the bad things that today's youths are doing.

"But you don't hear about things like this," he said.

Contact staff writer Aaron Claverie at (951) 676-4315, Ext. 2624, or e-mail aclaverie@californian.com.