I am in Mississauga, Ontario and the leaves on my roses are changing colour starting at the tip. They are are planted in a sunny area.
Thank you for contacting the Toronto Master Gardeners about the leaves on your roses. Assuming that your roses appear to be otherwise healthy, I think what has affected the leaves is leaf scorch, which we have seen quite a bit of this summer. Prolonged high temperatures, hot and drying winds, and low rainfall are the most common reasons for leaf scorch. With these weather conditions, large amounts of water evaporate from the leaf surfaces, and the plant roots are unable to provide enough water quickly enough to replace what has been lost by this transpiration. Leaf tissue dies as a result. Typically, leaf scorch appears in July and August, first on the side or sides of the plant most exposed to sunlight and prevailing winds. Plants may lose some leaves as a result of leaf scorch, and it can weaken the plant, making it more susceptible to insect infestation and disease, but leaf scorch alone won’t kill a plant.
There are a few of things that you can do for your roses :
- Additional watering : Roses prefer well-drained soil, and it is important to keep them well hydrated (not soggy). Typically a thorough deep watering every week or so is sufficient, but supplemental watering is likely required during hot, dry weather. After watering, the soil should be soaked to a depth of at least one foot. Watering should be done when the top couple of inches of soil is dry.
- Mulching : Add about 2-3 inches of organic mulch to the surface of the soil around your plant (about 6 inches away from the base), if you haven’t already, to conserve soil moisture and reduce watering frequency.
- Fertilizing : Roses are heavy feeders and should be fertilized regularly to maintain plant health and vigour. Strong, healthy roots will provide optimal water uptake. Typically fertilization for roses is done in the early spring and then regularly until late July, based on manufacturer instruction.
Aug.20,2022