Horticulture is an important source of naturalized plants, but little is known about naturalization frequencies and possible patterns of naturalization in horticultural plants. We analyzed a unique set of data derived from the detailed sales catalogs (1886-1930) of the most important early Florida plant nursery (Royal Palm Nursery) to detect naturalization patterns of these horticultural plants in the state. Naturalization status of these plants is based on the Atlas of Florida Vascular Plants (2006). Of the 1908 non native species sold by the nursery, 15% naturalized. Logistic regression indicated that the number of years a plant was sold was the strongest predictor of naturalization, followed by plant native geographic distribution and life form. Plants that naturalized were sold for an average of 15.5 years compared to 6.8 years for non naturalized plants. The naturalization rate was 70% for plants sold for 30 years or more. Plants with pantropical distributions and those native to both Africa and Asia naturalized were more likely to naturalize (42%) than plants native to tropical Asia (16%), tropical African species (9%), or tropical America (11%), suggesting that plants with large native ranges were more likely to naturalize than those with small native ranges. Naturalization rates also differed according to plant life form, with the most naturalization occurring in aquatic herbs (36.8%) and vines (31.2%). Naturalization of plants belonging to particular genera and families was also a good predictor of the propensity for other members of these taxa to naturalize in Florida.