Eric Brown and Sam Long know the best way to take care of overgrown junipers. Power up the chainsaw and cut them down to the ground. Many people attempt to shape overgrown spreading junipers but this is often a losing battle. When junipers cover up the front of a home or business, overtake the swimming pool, spread out into the street, cover up the sidewalk, or otherwise create problems, it is time to pull out the chainsaw.
When Eric and Sam finished the job, DH Surveys, Inc., on Chipeta, was visible from the street. You no longer had to crawl through the shrubbery to get to their office. And, the sign advertising their business was no longer hidden by the overgrown junipers they removed. Several trailer loads of brush ended up at the compost site due to their efforts.
There is a point beyond which you cannot prune back junipers. We call this the "dead zone" and once you cut into that zone, you are in trouble. These dead sections may never fill back in. Sometimes new growth from above can drape over these dead sections and mask the dead sections but that may take years.
Gardeners don't always take the mature size of plants into account when they select trees and shrubs. They forget those one gallon spreading junipers may have a spread of 25 feet and grow 12 feet high by the time they are mature. Everyone has seen walkways blocked by spreading junipers, spruce trees that have taken over the sidewalk and need to have a tunnel cut through to get to the front door. Some of the local landscapes I've seen remind me of TV documentaries showing explorers cutting their way through the jungle with machetes.
It is always best to remove troublesome plants and replace them with plants that don't outgrow the designated area when mature. If that is a strange concept to you then you should plan on replacing overgrown plants every few years. I would suggest you talk to your local nurseryman about the growth habit of the plants you are planning on buying. They should be able to tell you the mature height and spread of the plants they are selling.
Your nurseryman should also be able to tell you of any problems trees and shrubs are subject to. A good example of a problem is the basal suckering some crabapples experience. Most crabapples are grafted, i.e. a bud of the desired tree is grafted onto the root system of a different crabapple. Sometimes the grafts have problems and suckers grow from the base of the tree. Removing suckers from these trees is an annual process and if you miss a year or two of this task, the suckers will often outgrow the tree. There are sprays that are supposed to work but I haven't seen much success with these materials.
Cutting the suckers off is the best suggestion. An even better suggestion is not to plant these varieties in your landscape in the first place. Some varieties of crabapples are notorious for suckers and should be avoided. Planting trees too deep can increase root suckering. If you hire a landscape contractor, designer or architect, these troublesome trees should be avoided. When you end up with one of these trees in your landscape the best way to correct the problem is to tear out the tree and replace it with a tree that does not sucker.
Dr. Curtis E. Swift is a retired horticulture agent with the CSU Extension. Reach him at Curtis.Swift@alumni.colostate.edu or check out his blog at http://SwiftsGardeningBlog.blogspot.com. He owns Swift Horticultural Consulting and High Altitude Lavender.