No TDS. This is a contract for sale. You are not providing any raw material to the flower seller and neither are you selling to him any thing to manufacture the product and sell back to you.
However if you have following arrangement with him:-
1) You supply to him or provide him with a vase or basket and ask him to place the flowers in that and send back to you, it is a contract u/s 194C. In this case TDS is only on the service charge of placing the fowers in vase or baskets and not sale of flower if details are separate. However if breakup of charges and sale is not given then TDS is on entire bill.
2) You ask him to decorate the office with the flowers then again it is a contract and you should ask him to separate his service charges and do TDS only on the service charges. If no breakup, then TDS on the entire bill.
3) If the person comes to your premises and does Ikebana flower arrangements, it is better to have a separate bill for services and flowers as Ikebana comes under technical fees that attracts 10% TDS.
Do as applicable in your case. If you are simply buying flowers and the person is supplying it to you with office delivery as his responsibility there is no TDS. His activity is selling you the flowers and not the transportation as that is auxiliary to his selling activity. If there is a contract for any of the 3 instances above, get details separated in bill and deduct TDS accordingly.