On April 23, 1981, the Postal Service issued a sheet with 4 stamps (Scott 1876 to 1879 ) depicting flowers that are typically found in American gardens.  The flowers, which are rendered in red or pink on a pink background, are the dahlia, camellia, lily, and rose.

Fleetwood created a handsome series of cachets for these 4 stamps, in its trademark colorful and attractive style. They also include a fifth cover with the block of 4 stamps on it; that cachet features a fifth popular American flower, the tulip. Each cover has text on the back that explains the stamp on the front. These 5 covers would be a fine addition to any first day cover collection, or as a gift to the gardener you know!

Check the scan for details.