Hydrangea Black Leaves
Zone 6a Planted (2) twist-n-shout hydrangeas on 5/27/17 on new berm with compost and topsoil mix. Fertilized at that time with miracle grow and then put down hardwood mulch. Fertilzed again on 6/19/17 with miracle grow. On 7/4, I noticed one of the hydrangeas wilting with some of the leaves turning black. The texture of the black areas are crispy to the touch. Watering has been about 1-gallon 3-days per week in the morning (hand sprayed). I stopped watering last week and haven't seen any improvement. What is going on?
This looks like transplant shock. I would continue with the TLC but instead of watering by hand place a hose with a slow flow at the base of your plants to thoroughly moisten the root ball. Since the plants are slightly elevated the water could be running off and not getting to the root ball. Also make sure the mulch is not touching the stems of the plants, there should be a 6 inch ring around the base that has no mulch. There could also be stress if the plants are receiving direct sun and they were in the shade previously.
Ok. Thank you. Should I fore go further fertilization this year? Also, how should I protect the plant during the Winter?
If the plant is hardy in your area there is no need for any special care. Do not prune the plant in the fall and wait until you see new growth in the spring before pruning off areas that may not have survived the winter. Yes, skip any further fertilization for now.