Apply to local nurseries and garden centers. Apply to local landscapers. Any of those will be hands-on experience. Join groups that you're interested in such as the Perennial Plant Association etc. Attend trade shows. Get on the mailing list for your local Extension Service. There are many grants available from groups such as the PPA for young professionals so be sure to check these out as they could pay your way to meetings. Talk to everyone in the industry you meet.

We had a young grad with a B.S. in biology working in a garden center where I worked before starting my own business. It did not prepare her for any of the work we had available and she had a strictly entry level job. I guess I am saying that you need to be prepared for the 'hands on growing plants' part of it, your degree may proved to be disappointing. There are other areas of the industry where it would buy you a professional position and good pay. Why did you decide to major in that, instead of hort? Would you consider going into a different sector of the business like an ag lab, seed or plant industry, inspection, sales?