The tillandsias are secured to the cork with a double strand of 20 gauge coated steel wire. The wire is wrapped around the base of the plant and then twisted together on the back of the cork. You will need to drill two holes in the cork to get the wire to the other side. Twist and tighten the wire so the plant is held firmly. Be careful that you do not damage the plant when tightening the wire. Once attached to the tree the tillandsias are easy to water with a hose. All the moisture that the tillandsia receive will add to the humidity in tree canopy. The added benefit is that the plants will get plenty of dappled light and air movement, just as they would in their natural habitat. Your tree garden will do better with more plants than with fewer.