Have you ever wondered the best way to cut back your perennial flowers in spring? If so, you might want to watch the video I made of the general process. You’ll be surprised how simple it is!
In the video, I cover when the best time of year to cut back your perennial plants, how high to cut them during spring cleanup, and how to deal with perennials that have already started growing.
Here’s the basic information I cover.
The best time of year to cut back perennials along Colorado’s Front Range is February and March.
It’s good to cut back perennials after the severe cold of winter has passed, but before they start growing rapidly. That tends to be in February and March along the Front Range.
This year, because we’ve had so many intermittent spring snow storms, it’s been difficult to get everything done in February and March, so it’s okay to get to it in April. Most plants haven’t started growing rapidly just yet. However, they’ll start growing quickly once the weather warms up for a few days in a row, so getting to it soon would be great!
If a perennial hasn’t yet started growing, it’s best to cut last year’s growth the ground level.
Last year’s growth of herbaceous perennials is totally dead and will never regrow. This year’s growth comes up from the crown at ground level. So, it’s best to cut off as much of last year’s growth as possible so the plant looks green and healthy all the way to its base. There’s no reason to leave some of the brown stems if you can cut them off without damaging the new green leaves growing at the base of the plant.
If a perennial plant has already started growing, cut off the stems of last year’s growth right above the new green leaves.
Lots of perennials green up early, before it’s practical to cut them back. In this case, it’s fine to leave some of last year’s growth on the plant to avoid cutting the new growth.
Last year’s stems and leaves will not do the plant any good this year since they’re dead, but they won’t do any harm either. On the other hand, if you cut the new growth during spring cleanup, it makes the plant look overly trimmed and strange for a while- just like when people get strange haircuts. They have to produce new leaves and stems to look normal.
To avoid cutting the new growth, I usually cut the old stems 1-2 inches above the new leaves. In a few weeks, the new growth grows over the old stems and hides them from view for the year.
See how easy it is? So get out there and cut back your perennials this weekend!