She's on a mission to restore sickly magnolia tree to magnificence
Q: I have a magnolia tree that is looking quite sickly in the past six months. On our property where we planted the magnolia, we used to have three very large, very old pine trees that we removed for safety reasons. We had the three stumps ground, not very deeply however, and have since discovered a labyrinth of roots throughout the yard. We had a landscaping company come in and install the magnolia, which we purchased from them, and they were able to dig a hole large enough to plant it. For the first year, it looked beautiful, but this year it looks sparse and sickly. Are the dead pine roots poisoning our tree? If so, short of digging it up, traumatizing it more to transplant it, is there anything we can do for it? Gina DeMeo, Clearwater
Dr. Hort: After viewing your excellent pictures, a few scenarios come to mind concerning the lack of vigor of your tree. It appears that you purchased a Magnolia grandiflora "Little Gem," a relatively new dwarf Southern magnolia selection. When magnolias flower, the older leaves turn yellow, recycling nutrients back to the plant, before they fall. The heavier the flower show, the more pronounced the leaf drop, followed by the new spring foliage.
Another possibility is lack of water. Magnolias are happiest in a wet environment, and gauging by your photos that length of time would be approximately two to three years. I also noticed that it was planted on a hill shedding water. A crater would have been better for collecting water.
The last scenario has to do with planting depth. Plants for landscaping — especially trees — need to be planted with the top of the root ball even with the existing soil, or preferably 2 to 3 inches higher. It is a common mistake to plant large specimens too deeply, because of their weight, causing a slow death of the tree. Dig around the base of your magnolia with your hands in search of the first horizontal root, it should be right under the mulch. If not, keep digging. If your search finds you several inches below grade, the tree will have to be dug and placed properly. It would also be a good idea to move the mulch back from the trunk 1 to 2 feet. The pine roots are not a contributing factor. The case of the thinning magnolia will come down to natural causes or it was planted too high or too low.
Gina: Thank you so much, Dr. Hort. We are taking the steps that you outline (short of digging it up and moving it) and our fingers are crossed that it starts to perk up. Are there any fertilizers or soil boosters magnolias like? We will dig it up if it turns out it wasn't planted correctly. However, when we dug with our hands around the base of the tree, we did discover the roots started right under the mulch on most of the tree.
Dr. Hort: The root issue appears to be good news. With the information that you provided me, I believe the problem is insufficient water. The way it is planted on a berm, water is not staying in the root zone long enough for root absorption. You will need to provide supplemental irrigation.
Purchase a product called DripLine or equivalent with staples to pin it to the ground. It will be plastic tubing with a drip emitter every foot, which you will want to wrap in concentric circles 1 foot apart, starting at the trunk, to a diameter of 8 feet, placed under the mulch. The tubing can be hooked up to a water faucet and run every other day, if needed, to wet the soil to a depth of one foot, to encourage roots to grow out and down After your irrigation is in order, purchase an 8-2-12 fertilizer with micronutrients and 50 percent slow release nitrogen or equivalent and apply according to label directions. (In Pinellas County, Garden & Hardware carries the 8-2-12.) Once the magnolia roots reach the flat area of your landscape you should be in good shape, 1 to 2 years with your new watering scheme. You'll have the best looking magnolia in your neighborhood very soon.