SECRET GARDEN: On Tuesday night, Louis Vuitton will transform its new in-store boutique in Saks Fifth Avenue’s flagship into a garden. Le Jardin Louis Vuitton will feature various vignettes exploring the craftsmanship that is signature to the 155-year-old house, amid abundant flora. Guests, including co-host Maggie Gyllenhaal, will be directed to an elaborate “wishing tree.” The in-store boutique is the first location within a leased department to carry the firm’s ready-to-wear, and it is also the first women’s concept store in North America. Cruise is being launched there, as well. “We are pleased to be able to hold the worldwide launch of the 2010 cruise collection in this exciting new boutique and to continue our long-standing partnership with Saks,” said Daniel Lalonde, president and chief executive officer of Louis Vuitton North America, who also is hosting the event alongside Saks chairman and ceo Stephen I. Sadove. In tandem with the event, Vuitton will make a donation to the organization Partners in Health.