Wildflowers, redbud and dogwood will decorate the roads of Virginia when 200 private homes and gardens are opened for the state's Historic Garden Week from April 20 to 28.

Most of the houses, many dating to the 18th century and furnished with antiques, are grouped in tours of five or six, with tour tickets $7 to $12.Admission to individual homes and gardens is generally $2 or $3. There are 33 tours, from Albemarle and Alexandria to Williamsburg and Winchester.

All the homes and gardens open are described in a 194-page guidebook available free at Historic Garden Week Headquarters, 12 East Franklin Street, Richmond, Va. 23219; (804) 644-7776 or 7141. To get the guide by mail, send $1 for postage.