Time and again, firms have shown that even though a market seems to be saturated, one can succeed by either doing better than the competitor and taking market share away, or simply by expanding the market. Moreover, this type of production may also be about the only way to compete with mass marketers. You must offer products they and others don't have. As a small business, you have the ability to change products fast, and should do so as others take them on. To render such, read all you can, attend all horticultural training sessions, become certified, and join professional organizations.
Bedding plants seem to show little or no limits to popularity, and do offer a great market choice.
However, production of high quality bedding plants generally requires a greenhouse. Another lucrative alternative could be perennial production. Many nurseries have enjoyed great market success with perennials, as this area has so many niches to choose from and specialize in. Success will be much harder to come by if you choose to produce and compete with nursery ornamentals. This commodity is now produced proficiently and economically by most local nurserymen.