This is why you don't ask for graphic design advice from people who are not qualified to give it.
As a graphic artist (I worked in print advertising for ten years), I see it all the time here (and elsewhere)...
"Hey, how does this look?"
"Looks great, but you should capitalize everything.
"Add a clump of grass and it will be PERFECT!
I could poop on a sheet of paper and draw a lawnmower next to it and JUST because there's a lawnmower there, LAWN people would say it looks "GREAT!"
I know this is coming off wrong. I don't mean to be a dick, but seriously, you aren't really expecting calls from "high end" clients with that flyer, are
You could use that same info and make a few small changes and it would make all the difference in the world, because, yes, as it is, it looks "childish" for lack of a better word.
OK. Now for constructive criticism:
I do like the smiling sun. It's casual, but it's "happy" and "positive". If you carry that image onto all of your promotional pieces, it gives you a consistent image that people will remember. I'm betting the ladies will key in on it, and I don't know about anyone else, but I work for a LOT of women. It doesn't "pop" as much in black and white, but that's OK.
The biggest issue with the images used are that there are three different "styles" of art - it looks like you just grabbed whatever you could find.
The sidewalk portion just needs to go. Period.
If you must use a tree, please find one that doesn't look like a drawing that has been photocopied ten thousand times. It's just a bad piece of art.
A good layout must always have an attention getter. That could be an image, a headline, whatever. Look at your flyer - there isn't one thing that is dominant - all the elements are fighting for attention.
Typical of almost every amateur "designer" is the placement of the business name at the top. With some exceptions, that is almost always the wrong place for it.
A HEADLINE/attention getter/call to action should be at the top.
with Signed Contract!
Let Us Take Care of Everything
Company info and phone number should be at the bottom.
The box around the phone number has no real purpose - remove it.
I would remove "Services Offered". It just sort of "floats there" and the services "offered" are pretty obvious without needing to "say" it.
Full Service Lawn Care
Mowing Edging - Line Trimming Blowing - Hedge Trimming -
Weed Control Select Pruning
New Design and Installation Annual Plantings Clean Outs
Sod Mulch Rock Soil Tree Pruning
Repair Yearly Maintenance Additions French Drain
Removal Trimming -Topping - Stump Grinding
Note that things like the "dash" at the end of a line shouldn't be there.
Also, broken "descriptives" should be avoided - keep them on one line. see: "French Drain Installation" above. If it's too long for the first line, bump the whole thing to the next line - don't break it up.
Hope that helps. I apologize if I'm coming off too harsh.
Good luck! The pizza box arrangement could be a really positive thing. I just hate to see you waste such a great opportunity by not putting in just a little more effort into promoting yourself effectively.