Overall looks pretty good. However I'd consider reversing the colors (make white part green/green part white) or at least adjusting the black on green font. Some people will find it difficult to read.
For SEO purposes your home page needs more content, even just a short paragraph describing the 3 main pages of your site would help. Your pages also need better headings (the landscaping and snow removal don't even have one) relating to your keywords.
Really like the request an estimate form on every page (I do the same), after all - the primary goal of a website is to get potential customers in touch with your business, everything else is secondary. That said you could use some kind of call to action (do you do any promos for new customers?). Also, you might want to consider requiring the property address, this can allow you to check out the property on google maps before you talk to the customer.