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To root barrier or not to root barrier, panels or rolls, surround or lineal? What should we use when trying to protect our valuable hardscapes? I hope that this article will answer some of the questions that project owners, architects, landscape contractors and urban foresters might have about root barriers that are being used more and more each day in the rapidly evolving green industry. Should root barriers be used to protect hardscapes? There was a study done in California that many people have referred to placing a $70.7 million price tag on conflicts between street tree root growth and curb and gutter and/or sidewalk repair in 18 cities. The four most important mitigation and preventative measures sited and funds spent on each were to remove and replace trees in conflict with hardscape ($6.8 million), inspection and repair administrative programs ($5.9 million), root pruning ($2.5 million) and root barriers ($676,85). In reading this it seemed to that root barriers being the only pre planting preventative measure and the least expensive of the four measures it would make sense to install more barriers to decrease the later more expensive costs of removal and repair. Most of you probably know it is difficult to choose an effective product that is readily available and budget friendly in a constantly changing marketplace. To date there has been many different materials and applications used for root control and hardscape protection. Some of these include poured concrete trenches, prefab circular enclosures, rolled or plate steel and copper mesh to name a few. Dues to cost factors, effectiveness or availability these show up less and less every year. There are three types of root control that have risen to the top due to feedback from landscape architects, estimators, purchasers and field supervisors. The most widely specified products is a root barrier panel which is made from a polyethylene material at least .085 mil in thickness with vertical root deflecting rib 3/4 inch raised every 6 inches and male/female connections on each end. Panels come in various standard depths which include 12"(root pruning), 18" and 24"(most widely used size for new plantings), 36" and 48"(larger tree installation or maximum root protection) and sold in two foot lengths. The second root barrier is a lineal barrier which is manufactured from a polystyrene material at least .060 mil thickness with raised 1/2-inch vertical ribs every 6 inches and couplings which once glued are air and water tight. Lineal barrier comes in 12", 18", 24", 36" and 48" depths and is 20 foot long. This product seems to be more popular among contractors due to ease of installation and cost factors. The third root control product is very popular among architects and contractors due to its effectiveness, low cost and ease of installation. It is basically the 20-foot lineal barrier cut to certain lengths specified by the contractor. On a surround application the barrier is cut per tree size (15 gall, 24" box, 36" box etc.) With a connector pre glued at one end. So if you have thirty (24" box trees) your sent 30 precut barriers 24" deep and 108" long. Wrap the barrier around the root ball and insert the male end into the connector and glue this creates an air and watertight barrier around the root ball. Now that we have gone over the usefulness of root barriers and the different types of root barriers we should look at the most common application of barriers. While in the past and under certain circumstances with small planting areas a surround application has been common place. Most urban foresters, arborists, architects and contractors surveyed feel that a lineal installation is more desirable for the trees root system due to soil volume for root growth and stability of the tree. Also it is easier to install in most cases because its set inside the irrigation line trenches that are already excavated running parallel to your hardscape. Villa Landscape Products Inc., located in Placentia, Calif. has been manufacturing and supplying root barriers to many of the largest Landscape Contractors in the western United States. Specifications of root barrier products can be accessed at Or call 800-654-4067. hello

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December 10, 2019, 6:55 pm PDT

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