Qualifications
Education and experience help with getting the better jobs in management and sales. Some sales representatives at large wholesale nurseries and factory growers that supply retail outlets may be more educated and experienced in sales than horticulture. Sadly, many sales representatives know very little about the plant material that they sell. Likewise, many members of management who are so proficient with managing things may not know how to get their hands dirty with a bucket of mud and worms.
Just like most other horticultural industries, those who're the actual "horticultural" aspects of wholesale nurseries are at the bottom of the heap. Even then, those doing the real horticultural work often lack experience or horticultural knowledge - they're hired to water plants and schlep shrubs, not be scientists. While this can make it easier to get a job, but it can be frustrating for those who got a B.S. in horticulture to watch somebody who didn't work nearly as hard get paid the same amount.