I'd say go with your passion. No matter how good at something you are, if your heart isn't in it, you will never be truly satified by it!
Mix them somehow. Make what you love into what you do. Horticulture + Business = Manager of a floral design shop? Garden Landscaping specialist? Hydroponic Agricultural researcher? Sounds cool to me.
Could major in horticulture and minor in business...and start a business in tropical plants?
Isn't that what you love?
If you love something, you need to do it! My mum was in horticulture for a while, she loved it! I think you should follow your passions and what gets you excited, that is the most important thing; your happiness.
No problem, best of luck!
I didn't tell you what to go for, I gave you my thoughts to guide you to your own decision. ; )
Go to the local community college and talk to the guidance counselors, AND go to your local employment office and talk to one of the employment specialist about the fields you are interested in and then make a list of pros and cons for each field.