You'll want to take a look at the Google search results for keywords that best suit what you're trying to accomplish, ie "landscaping jobs" and then try to rank your hiring page to fall in to those results.
It's no different than any other page ranking strategies for specific keywords, but you're probably going for even more specific, less-trafficed words in [landscaping jobs in city] in what will probably be a very crowded first page of results (indeed, simplyhired, thumbtack, craigslist, etc will probably be on it). All depends on how competitive, or large, your city is.
I know lawn & landscape marketing, branding, and web strategy. I'm not anonymous, I just don't self-promote.