Try the school of hard knocks. When I hire, an applicant with education definately gets a second look but it is not the final decision maker for me. In this area nothing is required that I know of. A horticulture degree would definately be helpful.
Every big landscaper (over 1 mil per year in sales) that I know of has his or her knowledge gained from experience and luck(being at the right place at the right time). Schooling will not hurt, but I would hire somebody that has been working in this field for a while over a person with all these titles and degrees. Horticulture & even some types of farming degrees could apply to the landscaping field. The principles are the same.
The importance of education depends somewhat on the type of position in the landscape industry that you are interested in pursuing. This is definitely an industry where knowing the information is most important although a certificate or degree can make a difference at some point. A Bachelor's degree in horticulture is good for many jobs. If you are interested in job qualifications in classifieds, e-mail me and I'll try to put together a list of sites to visit.
Forgot about landscape architect degree. I think this degree could almost be better than Hort. (sorry Lanelle) I know I would love to have someone that is qualified to do designing on my staff. Probably couldn't afford the salary though.
While I appreciate the focus of most posts here, I want to take this opportunity to encourage any and all readers to achieve the highest level of education possible. Personally, I have a B.A. in Political Science. True, this is a liberal arts type degree, but its useful nonetheless. A four year degree of any type shows that you are educated, ambitious, and able to finish something that you've started. For younger (16-20) readers, I suggest going to college directly after High School if that floats your boat. Don't wait until later in life. Its much harder to finish later on, and while you are young, you can probably work your own business simultaneously. I firmly believe in this approach, and even for guys that aren't interested in turf or horticulture, I welcome them to my crews for summers, or part time if they are at local colleges. I have had guys study for masters degrees while plowing snow and cutting lawns.
The Hort degrees, LA degrees, some of the turf majors are all useful if you intend to specialize. However, don't rule out business and economics classes, accounting, or any other subjects. If you want to WORK in the green industry, especially for a large company, sure the degree will open some doors, but if you want to OWN a company, it may help to have wide open Horizons. For instance, down the road, my staff will have all of the necessary degrees as I determine to be useful. If you specialize, you will be locked in to those tracks. My point is that if you get a 2 year associate degree in turf or horticulture, what happens in 10 years when an opportunity comes along that requires a four year degree, or if you want to change careers. While the initial degree may be helpful, you will still be short a couple of years in the big picture.
I agree with SLS and would even broaden that. Every off season I take classes at the local technical college - I have a BSBA, with some engineering credits and Spanish cert, but take classes in winter including landscaping (different specialties), art, small engine repair, etc. Hope to find a welding class this winter. To be the owner of a small outfit, you have to be able to wear many, many hats, and education is key. You should always, 24/7, be looking for ways to gain more knowledge.
Now, to answer the question more directly, in WI nothing is REQUIRED. To call yourself an LA you have to be certified as such.
How many people do you know who are actually working in the same field as their degree? I don't know many. I agree that having a degree shows agressiveness and ambition but I don't neccesarily think it matters what field the degree is in. A degree shows that one has the ability to learn. One more semester of night classes will get me my BA in business. I have yet to actually use a lot of what I learned besides the major principles of econ and management principles. Do I think it was a waste of time? Certainly not.