Rose trees do not exist naturally, but are actually rose bushes that are pruned and grafted to resemble trees. These "trees" have trunks that usually stand 3 feet tall, with a rounded mass of roses at the top. Floribundas and Hybrid tea are types of roses used for creating trees. Sometimes, however, harsh weather or fungal diseases damage these trunks. Immediate repair is required to restore health, so the rose tree continues producing healthy blooms for many years.
Prune off weak or unhealthy canes (stems) with a sharp pair of pruning shears to reduce the weight on the trunk. Begin with weak, diseased or unhealthy canes and prune all the way down to healthy buds.
View your rose tree to decide how many wooden stakes you need to drive into the soil around it, and their appropriate height. These stakes are essential for supporting the canes. Generally, you need one stake for every 3-inch trunk diameter. When deciding stake height, keep in mind that it should be higher than half the tree’s height after an 18- to 20-inch length is buried in the ground.
Insert a wooden stake into the ground with a stake hammer, a foot away from the trunk. Your rose tree will lean to the side due to the heavy weight it supports. Drive the stakes all around the tree.
Knot an end of polyurethane strip to the stake and extend it around the trunk. Wind another strip around the trunk and knot it at another stake. Do not knot the strips too tight, as the roots of the rose tree can be adversely affected.
Inspect the union of the graft--the point where the rose canes and existing trunk were joined to form a rose tree--for spongy, white, swollen growth that resembles a tumor. This fungal disease is called crown gall and it enlarges and turns dark with the passage of time, causing blossoms to wilt and leaves to discolor and dry out.
Remove the crown gall from the trunk of your rose tree with a pruning saw immediately. Slice it flush with the trunk and discard appropriately.
Apply Gallex to the exposed area. Gallex is an ointment formulated to treat plants infected with gall disease. Follow manufacturer’s directions for applying it with a paintbrush and layering it over the spot where the gall was growing, including the area around it on the trunk.