Outdoor design plans for Westfield Group’s $350 million mall expansion in Woodland Hills were unveiled on Monday, with the company adopting a style that pays homage to San Fernando Valley’s agricultural roots. The company said it is aiming to create an “idyllic, shaded destination of sophisticated charm” with a layout, landscaping and décor that recalls the region before it was developed and urbanized. The Westfield Village project, which will connect the Westfield Topanga and Westfield Promenade malls, will feature fire pits, hanging basket chairs, communal tables, trellises and canopies, and a play area with a climbing structure. Landscaping will include olive trees, Mexican fan palms, crape myrtle and pink trumpet trees, along with plans for plaza spaces and a fountain. “People come to the San Fernando Valley to escape the congestion and bustle of other Los Angeles County areas, and yet, the area has lacked an outdoor space where people can simply stroll, relax, and not be reminded of traffic,” said Stephen Hamilton, vice president of design, Westfield. “It’s our mission to help guests — both local residents and visitors, alike — rediscover the beauty of the area.” The 550,000-square-foot mixed-use development will features shops, restaurants and a Costco that is expected to have a more upscale exterior design. Construction has just begun, with a completion date of fall next year. Westfield Village will feature more than 325 retailers and is expected to generate $1.2 billion in sales and employ more than 3,000 people.