HUNTINGTON BOTANICAL GARDENS: San Marino, Calif.; huntington.org or 626-405-2240 (for tours). Informal, walk-in tours available with admission. Tours requiring reservations include estate tours, $17; and "Tea & Tour," $49 (groups of four or more).

MIDDLETON PLACE: Charleston, S.C., middletonplace.org or 843-556-6020. "Camellia Walks" tours (free with admission) focusing on camellias; 11 a.m., March 13, 15, 17, 20, 22, 24; reservations required.

MISSOURI BOTANICAL GARDEN: St. Louis, Mo.; mobot.org or 800-642-8842. Guided walking tours (free with admission) offered daily at 1 p.m. Reservations required for tours of the park's Woodland Garden, Ottoman Garden, George Washington Carver Garden and more; fees vary.

MONTICELLO: Charlottesville, Va.; monticello.org or 434-984-9822. Guided tours of Thomas Jefferson's restored flower and vegetable gardens, tree grove and fruit orchards offered eight times daily April 1-Oct. 31 (free with admission).

SAN FRANCISCO BOTANICAL GARDEN AT STRYBING ARBORETUM: sfbotanicalgarden.org or 415-661-1316. Daily docent-led tours, family walks and birding walks (free with admission).

TOURS OF PRIVATE GARDENS:

ATLANTA: Gardens for Connoisseurs Tour, May 12-13, 10 a.m.-5 p.m., atlantabotanicalgarden.org or 404-876-5859. Tickets $30 ($20 in advance). Fund-raiser for the Atlanta Botanical Garden. Tour includes 11 private gardens, from a Japanese-themed garden to a woodland garden.

CHARLESTON, S.C.:

• Ashley Hall Tour of Homes and Gardens, April 21, 2-5 p.m. Tour of private dwellings and gardens in the historic district, to benefit Ashley Hall School, whose alumnae include Barbara Bush. Tickets, $35; 843-965-8454.

• Festival of Houses and Gardens, March 15-April 14; historiccharleston.org. Tours of private gardens in 150 historic houses in 11 colonial and antebellum neighborhoods.

• Garden Club of Charleston Annual Walking Tour, March 17-24, 2-5 p.m., thegardenclubofcharleston.com or 843-530-5164. Tickets, $40.

NATCHEZ, MISS.: Symphony of Gardens Tour, May 4-5, natchezpilgrimage.com. Thirteen town and estate gardens open to the public for self-guided tours, including Monmouth Plantation and Rosalie, an antebellum house owned by the Daughters of the American Revolution. Tickets $7 and up.

NEWPORT, R.I.: Secret Garden Tour, June 15-17; secretgardentours.org or 401-847-0514. Self-guided walking tour of private gardens in the Historic Point section. Tickets, $25 ($20 in advance).

VIRGINIA: Historic Garden Week in Virginia, sponsored by the Garden Club of Virginia, April 21-28, VAGardenweek.org or 804-644-7776. Thirty tours, ranging from private homes and James River plantations to the University of Virginia Pavilion Gardens, which were designed by Thomas Jefferson. Tickets $10-$40.