How to: Prune your hedges properly

By JEFF RUGG

Contributing writer

Q: My landscape guy pruned a long formal hedge and I think it is odd that he made it look like a pyramid with the top cut off. It is not quite that bad, but the sides are sloped and the top is narrower than the bottom.

I thought it should have straight up and down sides with the top and bottom the same width, but he says the sloped sides are the proper way to prune a hedge. What can I do to fix the hedge?

A: You may have asked the wrong person, because I agree with your landscaper to a certain extent. He is right that the proper way to prune a hedge is to have sloped sides and a narrower top and wider bottom. This allows more sunlight to reach the bottom branches. More sunlight means more leaf growth all the way to the bottom of the hedge.

The real question is how much of a slope did he prune into the hedge? All that is needed is around half an inch to one inch per foot of height. A four-foot tall hedge would be about four inches narrower at the top on each side. For artistic reasons, a person could prune the slope to be flatter at two or more inches per foot of height.

Rules

The first rule of pruning is that the first person to prune a plant can turn it into any shape he or she wishes, even if the shape has never occurred in nature before.

The second rule of pruning is that every person pruning that plant in the future will go brain dead and prune the plant to retain the same shape as the person in rule one.

Rule three says that if an extraordinary person ever decides to change the plants shape, they may do so, but it will take a long time to do so. The exception to rule three is, if a mistake is made, then the change will be done quickly.

If your hedge was pruned with a narrow slope and you can get used to it, then I say leave it alone and thank your landscaper for doing a good job. If the slope is too wide, then it will take some time to repair the damage.

Repair

Just like a bad haircut, we fix it by letting the plant grow out. Eventually, the plant will grow again and need to be pruned again. The parts that are okay will get pruned to where they are now, and the parts that are too short will not get pruned at all or not as much, so they can grow back and fill in.

Normally, we want to let each branch on the hedge be allowed to grow from half an inch to one inch in length each year. This gives a healthy plant, and the new growth will fill in any gaps to make a denser-appearing hedge.

If you can allow the hedge to grow vertically, say to block a view, then the top doesn’t have to be flat. It can grow to a point, just like a pyramid, or it can be rounded off on top like a gumdrop shape.

Flat-topped hedges in northern climates can accumulate so much snow that they break. Rounded tops help prevent this problem. If the hedge doesn’t have to be formal, you could let it grow out more and prune individual branches to allow a more natural shape.

For those that do have a hedge that is pruned flat sided, you can start proper pruning the next time you prune the hedge. Just leave some of the new growth at the bottom of the sides a little longer and cut back the top of the sides a little more.

What to do

Hedges that are just a little wider at the top may still have good growth all the way to the bottom and are easy to fix. Cut the top back more and let the bottom grow more.

Hedges that are already bare on the bottom are difficult to fix. Bare spots come from the lower portions not getting enough light, but getting light there now is not a guarantee that the plant will send out new branches to fill the space. This can be from improper pruning or from other plants like perennials and annuals growing in front of the hedge.

If these plants are touching the front of the hedge, they will cause bare spots in the hedge. Move them farther out from the hedge so light can reach the bottom of the hedge.

(Email questions to Jeff Rugg at info@greenerview.com. To find out more about Jeff Rugg and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.)