We are having a warm summer here in Oregon, with lots of days reaching the high 80’s to the mid-90’s. Yesterday was cooler, with thundershowers in the day time – refreshing, I thought. Today we are heading back to 90 degrees. I don’t recall a consistently warmer May-June-July, here in the Willamette Valley then we are having this year.
While mature peony plants are rather drought tolerant, we like to give them a nice, deep watering occasionally throughout the summer (unless we have some very good rainfalls). We water our baby peonies (1st and 2nd year plants) more often, as they are growing nice roots for dividing stock when they reach two years old. These field (ground) grown peony roots get deep watering and the soil will hold moisture around the roots for some time between waterings.
If you have peonies in containers that will be transplanted in the fall, they may need watering every couple of days in very hot weather, depending upon the size of the container. Nursery containers that are only 2 or 3 gallons will dry out rather quickly in 90 degree temperatures, while larger 5 and 10 gallon containers will hold moisture a bit longer. Water your containerized peony plants before they totally dry out. While potted peony plant roots are somewhat forgiving, they will suffer and become stressed from a lack of moisture. You can check the soil moisture with your fingers – you will feel if it is dry or moist. If the potted peony plant is very light to pick up, it is likely too dry.
While I generally like the soil in my container peonies to 'almost' dry out between waterings, I stress that they can dry out very quickly in ‘heat waves’ and consistently warm weather. Be sure to keep an eye out on both your container and ground plants (peonies and other garden plants) this summer and give them a good drink of water before you think they REALLY need it.
For more tips on watering plants (checking moisture levels, how much water to put in a container, potting soil mixes, etc.,) check out Container Gardening Expert, Kerry Michaels article What Should I Know About Watering Plants in Containers.
While keeping cool and hydrated in hot weather is essential for people, it’s also a must for plant health. Her descriptive information on watering container plants is easy to read and useful for all levels of gardeners.