The most important thing about referrals is the timing - asking when you have just blown the customer away with service, product, etc. That is when they will be most excited and feel the most obligated.
Are you using the FloristWare follow-up feature? This could be the place to work it in. When you follow up with a customer or recipient and they say you guys are great you ask them right then - they just volunteered how great you are and they are almost obligated to provide something just to appear consistent. You can also offer a credit, bonus points, etc. at that point without looking like you are buying testimonials.
