Another successful year in the garden is usually punctuated by an abundance of new, healthy growth on perennials and shrubs. In many cases, shrubs such as Buddleia may have outdone themselves and require pruning to maintain shape and size. Buddleia davidii is a summer bloomer and often will push blossoms well into late summer and fall. This is your indicator that pruning should not occur until well after flowering. The correct timing depends on your region of the country, relative to climate conditions. Basically, prune the shrub once the temperatures have dropped sufficiently so that no new growth is encouraged to start. November, for the most of Canada, is ideal, as the weather isn’t to miserable for you to be outside pruning, yet the shrub is already entering dormancy.
Buddleia will blossom on the new wood therefore a ‘hard’ pruning in the late fall or very early spring will result in more new wood and typically larger flowers. The term hard pruning is rather a matter of opinion but generally speaking, you can remove the growth down to about 30 cm (12”) from the soil surface. Timid or perhaps first-time pruners, may opt to leave more top growth, however, the results the following season will help make the pruning decision easier for the following year. Understanding that sunlight should reach all portions of the shrub should dictate that leaving larger, heavy wood particularly towards the centre of the plant is not a good idea. In the event that the shrub is quite mature and hasn’t been pruned for some time, you may choose to pace the pruning over a couple of seasons. Initially, remove the heaviest wood to within 30cm (12”) of the soil leaving the next largest branches until the following year. This scheduled removal will not harm the shrub and will maintain some semblance of shape and size to balance your landscape. Personally, I prefer to “re-work” the shrub by removing all the old wood on a mature specimen and in the following season(s) shape the shrub to suit my landscape.
Buddleia is often cited as a “deer resistant” shrub (if there really is such a thing) and a tremendous attractant for butterflies and other nectar seeking creatures. As this shrub may provide blooms well into late autumn, don’t be too anxious to begin pruning as these creatures may depend on it as a food source. This is one shrub that is known to over produce, so when deciding where to plant your Buddleia consider that they can grow easily up to 3.5M (10ft) in one season with a girth of roughly the same. Foundation planting in the landscape is definitely out, unless you chose dwarf varieties. It is important to plant your Buddleia(s) in a sunny location with ample room for them to spread out. The current emphasis on attracting pollinators to your landscape as well as other beneficial creatures has leveraged a strong demand for Buddleia for commercial as well as home landscapes, so make your choices and purchases early in the season to avoid disappointment.
Many varieties of Buddleia exist, with new introduction occurring annually One variety that I think is great is Lo and Behold® a marvellous dwarf member of the Butterfly Bush family. This specimen mounds to approximately 1M (3ft) and will spreads to roughly the same; a great addition for the smaller, urban garden. Tutti-Frutti is a gorgeous pink Buddleia that tends to grow a little taller and compliments the deep blue of Lo and Behold beautifully. Look for the varieties “White Profusion”,” Royal Red”and “Navaho Blue” to add to your collection of easily grown and maintained shrubs.
November 12th, 2017