Here are my thoughts on hiring the right people. IMHO this should be done by at least two different people and three to be good with the third being you the one with the final decision. If they have made it to you they should already have a idea of what to expect by say your lead that did one interview and a up and coming laborer maybe.
1. Must access general knowledge of the industry. Test them...do not be scared to ask a million questions. Can they identify the different types of turf you care for, what about the plants?
2. Must clearly set and gather their hours of availability. Must be on paper and they and you sign. Make it clear...on the paper...you are hiring based off that availablity...they lessen it or refuse to work during those hours....it makes it easier for you in unemployment hearing.
3. Judge their looks. Not if they are good looking but do they take care of themselves? Did they do everything they could to present themselves in their best light? If they did not bother to shower to come to interview...do you think they are someone you want talking to your customers if they do not have that respect for themselves...they most likely will not have it for your company and its assets.
4. When explaining the typical day to them...explain the worst days. Make sure they are braced for it. Don't paint a rosy picture.
5. Try to interview them in the environment which they will be working. Maybe the shop? Ask them to show you how to operate a mower if they state they have experience...did they check the oil before starting the engine? If so they will take care of your equipment...if not they will assume that somebody besides them makes sure the equipment in ready. Ask them to demonstrate simple things like changing a edger blade or line on trimmer. You would be amazed of the horror stories I have heard of peoples bad hires over the years, which include the persons who are suppose to have experiance but can not do this basic task.
Hold the interview outside in the heat of the day. Did the applicant act like he was going to die during the interview? If so do you think he is going to make it through a 12 hour day in it.
6. Last but not least....check references ....not personal...that is crap...you want previous employers and their opinion.