My first question is, is this shrubs or hedges?
My definition of the two is hedges are grown as a privacy fence and usually very tall 10+ feet high and sometimes very wide. They need not be that tall just yet, but they will, trust me. I saw some just yesterday that had an obvious stopping point of where they stop trimming to. My god they must have been 20+ feet tall - insane.
Shrubs are individual plants used as visual aesthetics.
Things to consider. Is this a regular customer of yours? Will they be having you do it yearly? Will you need a ladder? Do they want you to trim the neighbors side as well?
Q. Is it more work to trim an overgrown hedge/shrub than it is to trim one that was done every year? Not really. But really neglected S/H's may need some branches tied up to fill in bare spots and holes caused by low hanging heavy branches or branches damaged by heavy snow. So that time spent doing this must be considered in your price.
If they are a regular mow account, get them to agree to have you do it yearly automatically. This way you can schedule it. Explain the importance of yearly trimmed S/H's. Such as they grow healthier, fuller and less likely to succumb to damage of the heavy snow and wind. They are easier to shape and groom making for a real clean look when done. This is a selling point for the other side too. Lack of maintenance on the opposite side will result in poor growth and poor uniformity on either side. Plus this puts you in front of the neighbor and available for doing the rest of their S/H's also. I can't tell you how many times one S/H's job snowballs into doing a whole city block. Nobody wants to be that ass in the middle with the unruly S/H's when everyone else's looks so nice and groomed. (groomed - a word you should use a lot when communicating with the customer about S/H's. It creates a great visual and expectation for them unlike saying "...yeah we'll cut 'em back for ya...")
Ladder work is more dangerous and certainly more exhausting and this should influence your pricing. If I could do all my S/H's with two feet firmly placed on the ground, I wouldn't charge as much and I think I would actually enjoy it a little. This is the one time that overgrown S/H's pricing makes a difference. When cutting back an overgrown hedge from the top, you will find very large branches that your trimmer cannot cut. Either you need a chainsaw or some other pruning device. This takes more time and must be considered.
Bottom line. I charge an up-wards (sometimes more) of $2.50 a foot. Start adding in those other things like width and height and you'll be glad you did. Smaller areas and shorter S/H's I will charge more like $1.50 a foot. Consider the terrain also, will you be able to reach all those areas on top? Will the neighbor allow you to step foot upon their property to trim the top-side that you cannot reach from the paying side?
As far as actual shrubs, I have a sliding scale that is mostly based on time. It is hard for homeowner to justify paying $20 a shrub if it is 2 feet tall and 2 feet wide. I try to stick with the quick $1 a minute on those that just need to be cut back a little.
