Some gardeners have good luck with cutting
oriental poppy (Papaver orientale) to the ground
immediately after flowering. New basal growth
appears and remains to fill in the space through the
summer, rather than leaving a void for much of the
summer, which happens if plants are allowed to
mature and die back, and then are cut down. I have
pruned back poppies right after flowering for
several years now but have not had good luck. In my
garden the new growth doesn’t appear until
autumn—which is the same time it appears when I
don’t cut the plants down right after flowering, but
allow them to die down naturally and then prune
them. Besides, not cutting them down after
flowering allows me to enjoy the ornamental
seedheads that develop.Summer-flowering perennials
Summer-flowering perennials differ from the spring-flowering types in the
amount of cutting back that is required after flowering. Some plants look best if
cut to the ground, or to new basal foliage, whereas others require a cut by half or
a third, and still others need 6 in. left on top. Here individual needs come into
play. As with other pruning techniques, the cutting-back requirements of
perennials is greatly affected by the age of the plant, weather conditions, and soil
conditions. First-year plants may be vigorous and may flower most of the
summer without any cutting back, though in subsequent years they usually
demand it. If the weather has been extremely hot and dry, as in southern regions,
the plants are going to show more wear and will benefit from a trim to bring
some fresh new growth to the garden.
The degree of cutting back is also specific to each species. Looking at a few
plants from the genus Geranium gives us a good picture of just how individual
the plants can be in their needs. Geranium endressii ‘Wargrave Pink’ looks
unsightly in our hot summers if all the old stems are not cut back to the ground
where new basal foliage is forming; the closely related Geranium ×oxonianum
‘Claridge Druce’ and ‘A. T. Johnson’ need to be treated in a similar fashion. But
Geranium macrorrhizum and Geranium ×cantabrigiense ‘Biokovo’ require nothing(clockwise from top left)
Evergreen candytuft with
deadheads; evergreen candy-
tuft can be cut back by
grabbing a handful of stems
at a time; evergreen candy-
tuft after being cut back.
110 PruninG Perennials