By BETSY TAYLOR • Associated Press Writer As a Mormon planning a temple wedding, Jenna Gaal knew what she needed in a wedding gown: pure white, with sleeves and a conservative neckline and hem. She just couldn’t find it. ‘‘I tried on things that looked like nightgowns, floor-length with beads,’’ said the 23-year-old from Kansas City, Mo., who wanted something elegant as well as modest. Finally, she found her dress about a four-hour drive from home at Chatfields Boutique in the St. Louis suburb of Des Peres. Chatfields, which bills itself as ‘‘an unexpected wedding store’’ features modest, plus-size, eco-friendly, maternity and other specialty gowns. Its owner, Debbie Welcher, notes that not all brides are seeking a size 6 strapless couture gown. While those with unconventional — or very traditional — needs may have to do a little more homework, there are places where they, too, can find the dress of their dreams.