By early Fall, or maybe even late summer, my Day Lilies are spent. ...Tired. ... Done.
And they look bedraggled and messy.
When I prune them back by about half, I often find new wee buds lurking below the dead leaves. Especially on Stella d’Oro lilies. When I trim them back and remove the dead leaves, the sun can reach those struggling buds and give them another flush of flowers. Besides, it really tidies up the garden and leaves room to plant bulbs beneath the spent leaves.
If you cut back Sedum, Salvia, Phlox, Echinacea, Monarda (Bee Balm) in late May or June this will give you shorter, thicker, bushier plants with more blooms on sturdier stems (because these perennials bloom later in the season)
You can cut back each clump a different height to give more definition to your garden. They may look a bit naked for a few days or a week afterward, but before long, they will fluff up and produce more stems, and more flowers.
This is a clump of White "David" Phlox - Phlox paniculata in mid-May
...this is the same Phlox plant after having the stems cut in half. Last summer I did this, and the plant was fuller and the flowers more abundant. Keeps the stems strong and more able to hold the heavy flowers. This way, you can leaves some plants to grow their full height, and others can be cut by half, or a third. This gives variety of height in the garden.
so prune your perennials - especially in Spring for more, lush growth.
In the photos below, we cut back the sedum by half around the end of May. Here is what it looked like before and then see what we did with the clippings.
Here you can see we just stuck the cuttings in the soil in some leftover planters we had. No rooting, just stick them in... trust me, they will grow.
Here are those same cuttings the middle of August. .. Really ...
The Sedum about to bloom is tall.... almost 3 feet.... the short ones to the left, not yet ready to bloom (the bloom heads are still green) are the Sedum I cut back. This is a good way to get different bloom times, as well as different plant heights in a rather flat bed.
Here you can see the differing heights... this shorter Sedum in the front was also cut back in May and is a different colour than the others.
You could also vary the height in one plant by cutting back the front of it and leaving the back taller. It would give the illusion of depth in a small garden.
So be brave, be daring .... Pruning perennials works. It’s rather like deadheading annuals. It promotes more flowering and fuller plants. If you are a bit hesitant, and have more than one clump the same, prune one and leave the rest and see what happens. I am certain that next season, you will be pruning the others.
It is different than pruning roses, though.