Yesterday I visited these guys - Alan Petravich, Koa Kanamee and their chocolate Lab Hoa at their home, called "the blue bottle cottage" on the grounds of Longwood Gardens in Kennett Square. Alan, who grew up on a dairy farm in Pennsylvania, and Koa, who's from Hawaii, both work at Longwood - Alan's a research assistant, breeding clivias, trialing plants, working to eradicate viruses on cannas and crysanthemums, and Koa works on specialty crysanthemum forms, such as topiaries. They both love blue bottles, and, as they say in the newspaper biz, they are not alone. The bottles are gorgeous. The couple has a collection of more than 100; quite a few decorate their bottle tree - a oddly-shaped yew - in the garden. It's not the typical crape myrtle or cedar tree historically used in the South, and it's a far cry from some of the metal ones now being sold by garden supply places and entrepreneurs. But it's striking in a winter garden, set against the brown and tan seedheads and grasses, and the snow. Since I began researching this story, I've kept an eye out for blue bottles. Conclusion: There aren't many out there anymore. Used to be, in the South, everyone used Milk of Magnesia. And there are still certain vodkas, reislings and waters sold in blue. But most "bottles" are plastic now, I don't drink vodka or reisling, and I don't buy expensive water. Alan and Koa are lucky. They have many antique bottles and friends give them others. I have a feeling I'll be on blue-bottle watch from now on, everywhere I go, on the lookout for a blue bottle - or two - to requisition.