Do dormant perennials need water in winter?
Hello. I have large planters outside, one of which is partially under roof overhang. I have planted dahlia and chrysanthemum in that area and would like to know if they need supplemental water during winter. Some rain does blow in there and 3/4 of the area is open to the rain, so I don't know what to do with that back area. Thank you. I am in North Willamette Valley at about 400 feet of elevation.
Yamhill County Oregon
Hi, water does't just go straight down in soil, it spreads sideways as well. The plants' roots will actually survive winter freezes better if the soil is moist instead of dry. Why don't you check periodically this winter to see if the soil under the roof is dry. If it is, then you can water perhaps monthly or every 6 weeks.
Dr. Linda Chalker-Scott from Washington State University Extension wrote an interesting paper on the water needs of dormant perennials which you might find interesting and helpful. https://s3.wp.wsu.edu/uploads/sites/403/2015/03/winter-watering.pdf