DBA with the county and Liability Insurance is it. If you want to apply any chemicles like fert/weed killer your supposed to have that license. Some of the Big city area counties require contractor licensing for lawn care and landscaping but most dont. Ask when you file your DBA.
I'll tell you from experience the best thing you can do starting out is to get a decent accounting software and learn it. This way when tax time comes, you are all set. Plus you can do your estimates, and invoices on it, and it will always give you an accurate idea if you are making money or not. My company uses quickbooks online version, and it is the best thing that I ever did. (besides incorporating, which is easy by the way). Find a good quickbooks advisor (you can find on their website) go meet with them and have them set you up. I promise you will thank me. If you use Quickbooks online, and link it to your banking account, it will automatically import all of your credit card/debit transactions and match them up in the right departments for you.
If you don't incorporate right away, go to the bank and open a d.b.a. checking/debit account with your new business name. Go online with the state/irs and setup a sole proprietor business online, and they will give you a tax id number for your business immediately. (You probably have to do this before going to the bank) Get the liability, and worker's comp insurance, and away you go. We don't need any particular licenses in MA.
I know I strayed from your question, but I just don't want anyone to make the same mistakes that I made starting out.
keep it simple. Your solo for now. You dont need to be paying for workers comp. And many states dont require sales tax on services. I do work in western MA and I dont have to charge sales tax over there. If you dont have to DO NOT get a tax ID number!!! It will follow your business forever and expect you to send the gov money 4 times a year.
NO! If your services are non taxable you dont need an tax ID. Call your county clerks office to find out if maintenance is taxable. For me it is, unfortunately. The excavation guy that I use has no tax ID because its non taxable pretty much everywhere.
I just went through alot of this this past year. Feel free to send me a private message with any questions. I will help you out where I can. Big thing to remember about weed control and pesticides. YOU NEED THE LICENSE! If you charge to apply it, you need a lic. YOur customer can go into home depot and buy round up and spray it no prob. If you do it on their property and charge, you need a lic.