Thuja, also called arborvitae (Thuja spp.) Is a family of evergreen plants used frequently for hedges, accents and foundation plantings. The divisions are composed of sprays of flattened, scalelike leaves, accented by small, oblong cones. 1 well-known member of this group is oriental arborvitae (Thuja orientalis), which grows in U.S. Department of Agriculture plant hardiness zones 5 through 11, depending on variety. Though generally trouble-free, thuja may sometimes be subject to branch browning. Brown branches don’t necessarily mean the tree is dead.
Health Assessment
Prior to taking any action, identify if the branch or branches are dead or not. If the branch is dead, then it will snap off on your hands when you bend it. A living branch is flexible. Once you have ascertained if the departments or division in question are living or dead, start looking for other clues. In case lots of the branches at various places on the plant snap off, the thuja is probably dying or dead. If the problem is only in 1 part of this plant and most of the divisions are flexible, it is possible the thuja can be stored.
Climate-Related Problems
Hot, dry summers can cause thuja divisions to “flag” or turn brownish. Spreading a 2- to 3-inch layer of organic mulch around the roots and increasing watering until dry and hot conditions subside should help keep the rest of the branches green. Winter temperatures can be a problem too. If the winter is cold, leaf may turn bronze, brown or dark in reaction. Usually no action is necessary and the discolored leaf will turn green again as temperatures rise in spring.
Root Problems
Root problems may create parts of this thuja to turn brown. If the root ball’s shirt is well below the edge of the surrounding ground at planting time, then the thuja may fail because it is planted too deep. Similarly, if the young tree is root-bound at planting period, together with roots girdling the dirt ball, the tree will start to turn brown within its first year. Slice through circling roots and spread the roots out gently prior to planting to avoid this problem. Eliminate any burlap or twine from around the thuja’s root ball at planting or they may also prevent root development.
Thuja Treatments
A thuja that’s completely brown and dead should be eliminated and its root ball assessed for signs of problems. A soil test may help determine if soil variables were to blame. If death was caused by compacted dirt, a buildup of fertilizer, soil pH that is too low or root weevils, those conditions must be treated before you plant a replacement. If a herbicide was implemented nearby, and you think that may have murdered the thuja, wait until the following year to replant. If browned branches are caused by a treatable condition, prune them away, apply the right therapy and track the thuja closely for signs of recurrence. When pruning, use shears that have been wiped with a cloth soaked in rubbing alcohol. This helps prevent the spread of infection.