Biographies of American Seedsmen and Nurserymen Michell, Henry F.–Philadelphia, Pennsylvania–was a Swiss immigrant who started a retail seed business, Henry F. Michell Co., in an attic on Philadelphia’s Market Street in 1890.  His brother, Frederick joined him in 1892 and by 1900 the business had grown prosperous with a five-story facility with seven product departments and a separate four-story warehouse.  In the 1920s, the brothers expanded into the wholesale market.  In the 1950s, Frederick’s grandsons, Henry F. Michell, III and Frank Michell, Jr., relocated the headquarters to King of Prussia, Pennsylvania.  The company now offers greenhouse supplies, structures, and equipment.  The company is now owned by Henry F. Michell, III and Henry F. Michell, IV.
Sources: GG