Certified GKH Gardening Expert
Is the tree showing any signs of a nutrient deficiency? Are there any fertilizers that are being added to other areas of the landscape (i.e. lawn) and, if so, how much? Many times, trees will tell you if they need more nutrients. A soil test will let you know for certain if anything is actually missing. In general, mature trees benefit from fertilization every two to three years. One way to fertilize a tree is to broadcast granular fertilizer evenly over the area under the tree, extending to the drip line. Be sure to apply the fertilizer to moist soil or water it in immediately after application to avoid fertilizer-burn damage to the roots. Use a specially formulated evergreen fertilizer when feeding your Thuja Green Giant, assuming this is the mature green gaint you are referring to.