I recently purchased a 'Royal Purple' smokebush, despite the fact that I have...

Asked September 13, 2013, 2:10 PM EDT

I recently purchased a 'Royal Purple' smokebush, despite the fact that I have read online that this variety is only semi-hardy in MN and that the roots will survive the winter but there will probably be considerable stem dieback, resulting in the plant having great foliage color but never blooming or reaching its full size. However, during a recent visit to the MN Landscape Arboretum, I noticed a very large smokebush labeled 'Royal Purple'. It's near the annual garden with the fountain. The bush is huge and in full bloom. My question is: How did theirs get so big and how did the flower buds survive the winter? Are they doing something to protect it from winter injury?

Ramsey County Minnesota smokebush horticulture

1 Response

Thank you for the question. For such specific questions about how the Arboretum overwinters its Royal Purple smokebush, please call their Help Line 952-443-1426, or visit their Yard & Garden Help Desk in the Visitor Center, staffed Saturdays and Sundays, 10 am-4 pm. I have read that the Arboretum cuts their smokebush down to the ground each year and if it shows pink blossoms by the end of the season, it would be considered a success since growing it in Minnesota is slightly "iffy "due to its marginally hardy status here. For best results, make sure your plant is in a protected, full sun spot, water well until the ground freezes and then cut it off 1 foot from the ground. It can't hurt to heavily mulch the roots, and remember, the buds don't survive the winter, instead the plant will flower (hopefully) on new wood next year. Read this publication from the University of Minnesota Extension. Scroll down to "Planting on the edge/Growing the Unmentionables". Good luck! http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-Sept0199.html