Tip Sheet: Air Pruning Method Helps Critsite Develop Superior Plants

Air pruned plants don't just survive, they thrive.

Plants grown in open-bottom or perforated containers develop differently than those grown in traditional solid containers. In traditional pots, roots continue to grow down and tend to spiral which can make the plant root bound. In severe cases, spiraling roots will strangle and kill a plant.

In air-prune technology, special pots are utilized by the producer. As the tips of the roots reach the opening, they are exposed to air. Once the root is exposed to air, the tip dehydrates and stops growing. At this point, secondary roots form that are more horizontal in growth habit. These secondary roots will have similar reactions, developing tertiary branching, and so on. Air-pruning simply encourages more roots to sprout. The end result is a healthy plant with a fibrous, 'ready-to-grow' root system that develops a mature root system earlier and top growth 20-25% greater than its traditionally-grown counterparts.

Although only 4% of the nation's growers use the air-pruning method, the system is an industry standard for some. Florida's Grades and Standards for Trees, adopted in 1998, requires culling any container-grown tree exhibiting spiral root patterns. Ironically, traditionally-grown plant might look good from the crown up but have spiralled roots and may not thrive. Additionally, installers might not take time to cut away those problem roots. This neglect contributes to the national 10-year average life expectancy for urban tree survival.

In studies, air-pruned trees' caliper girth averages a 15% faster growth and rooting out rate is typically 25% faster when stock is stepped up into bigger pots or transplanted into a landscape. Critical Site Products' deep cell plug format has a 2 X 2 X 5-inch root mass. On average, herbaceous perennial deep cell plugs develop into a full-size plant within 41 days. Critical Site Products' trees and shrubs are propagated for 2-years in APM formats prior to release for sale. During the first year, seedlings are produced in a 2 x 2 x 8-inch super cell plug. These are transplanted into 1-gallon, 2-gallon, 3-gallon, 5-gallon, and 10-gallon open bottom and side perforated containers for growth through various tree and shrub sizes. Research has indicated that APM stock averages 40% greater survivability in comparison with ball and burlap growing methods.

Critical Site Products believes in growing superior plants…from the roots up. All of our more than 500 native species are propagated using air-prune technology.