This postcard is probably from the late 1930's, when Lake Avenue south of Colorado was known as the Oak Knoll Shopping District and was served by the Pacific Electric Streetcars.
As you probably know, Lake Avenue turns into Oak Knoll Avenue south of California Boulevard, with a few shops still south of California, such as the very old French Laundry and the former Jurgensens Market, now Fresh and Easy. The stretch north of California to about Green Street was made up of residential dwellings, many converted by the 1930's into retail establishments, similar to what is seen on North Lake north of the freeway today going up into Altadena.
South Lake remained nearly only residential structures, with restaurants and retail in some, until 1947 when the fashionable Bullocks Department Store was built just south of Del Mar. With the opening of Bullocks, more and more purpose built retail came to South Lake, such as I. Magnin moving from their beautiful Beaux Arts Style Colorado and Madison shop location to a new Streamline Moderne Style building just south of Bullocks, this in 1949.
Still, South Lake had many old homes hosting retail and dining up until the 1960's, when the Union Bank project between Cordova and Del Mar was built, spelling the demise of the charming Oak Knoll Shopping District and ushering in the upscale South Lake Shopping District.
A Japanese Florist managed to survive in a Victorian Style home just south of Wells Fargo Bank up until the 1990's, when it was demolished and replaced with a modern building. The Magnolia Lounge Speakeasy Bar just south of the Mobil Station, 492 South Lake, is located in a bungalow which has survived, well worth a visit. Another large home survives in the middle of the block on the east side at 142 South Lake, the present home of the Williams-Sonoma store.
The White House Country Store looks so inviting with its old wagons in front and promise of antiques. What antiques may have been available in 1939? Perhaps a Wells Fargo strongbox or an 1849 gold panning dish? One can only imagine.