Katherine Jackson -- Lemme Sell You Some Flowers

Katherine Jackson's business portfolio is continuing to blossom -- TMZ has learned Michal's mom is designing floral arrangements especially for Mother's Da


Katherine has personally helped put together 6 different floral arrangements for a website called SendHerFlowers.com.

Sources close to Katherine tell us the deal is 100% legit -- and Katherine has been family friends with people involved in the business for years.

No word on how much cash Katherine is expected to rake in from the deal.

Don't expect the Michael Jackson estate to get involved in this endeavor ... the site never uses MJ's name or image ... and only features a photo of Katherine.

By the way -- don't forget to buy your mom something nice this year ... she brought you into this world. Respect!