Look through botanical photo catalogs, source books, flower ads and collateral marketed to interior decorators, frame shop poster peddlers, and interior architects. You will find less than .01% of all floral images have an empty black background (I used to be in the business). If one asks for a critique, one should be prepared to see their work from a fresh set of eyes. My comments are well-meaning and intellectually honest. If the tulip guy wants to stay where he is at and get nit-picky about symmetry of stems and use the same type of lighting--basically the same technique, he will not grow as an artist/photographer. If he's interested in selling that type of work, good luck.