6 Perennials You Should Not Cut Back in the Fall

Fall always makes me want to clean up my garden.

Once the flowers start fading and the garden begins looking a little messy, it’s tempting to grab the pruning shears and start cutting everything back.

But I’ve learned that not every perennial should be cut back in fall.

Some plants are still green and actively storing energy for next year. Others provide food and shelter for wildlife during the colder months. And with certain plants, pruning at the wrong time can actually mean cutting off next year’s flowers.

I took a walk around my garden to see what I’m leaving alone this fall. Here are six perennials I’m not cutting back yet, and why.

1. Hydrangeas

Hydrangeas are one plant where I’m especially careful about pruning.

I actually don’t prune my hydrangeas as part of my fall garden cleanup because the right time to prune depends on the type of hydrangea you have.

My bigleaf hydrangeas bloom on old wood. That means the stems growing in my garden right now may already contain flower buds for next year.

If I cut those stems back in fall simply because the plants look messy, I could accidentally cut off next year’s flowers.

My Annabelle hydrangeas are different. Annabelle is a smooth hydrangea that blooms on new wood, so it’s much more forgiving when it comes to pruning.

The important thing is to know which type of hydrangea you have before you start cutting.

If you don’t know, I think it’s better not to prune your hydrangea at all than to prune it at the wrong time and accidentally sacrifice next year’s blooms.

Identify your hydrangea first, then follow the pruning recommendations for that particular type.

2. Astilbe

My astilbe is definitely past its summer prime.

The flowers have faded and the plumes are drying out, so I could easily cut the whole plant down while cleaning up the garden.

But I’m not doing that yet.

When I look underneath those spent flowers, there is still plenty of green foliage.

As long as the leaves are green, I don’t see a reason to remove healthy foliage just because it’s fall.

I also like leaving the dried astilbe flower plumes standing. They add texture to an otherwise bare winter garden and can look especially pretty covered in frost or snow.

I’ll leave mine alone for now and clean up the old growth after it has gone dormant or in late winter or early spring before new growth appears.

3. Catmint

My catmint is another great reminder that the calendar doesn’t always tell you when it’s time to cut back a plant.

It’s fall, but my catmint is still green.

In fact, I can still find a few little purple flowers on it.

Clearly, this plant isn’t finished for the season yet.

Eventually, colder weather and frost will cause it to go dormant. Once the foliage dies back, I can clean it up or leave some of the old stems standing until spring.

But while my catmint is still green and flowering, I’m leaving it alone.

4. Hostas

My hostas are probably the plants I’m most tempted to cut back in fall.

By this point in the season, they can look pretty terrible.

Mine have holes from slugs and snails, brown edges and plenty of other damage after a long growing season.

But when I look closely, many of the leaves are still green.

That’s what matters.

While the foliage is green, the plant can still photosynthesize and send energy back to its roots.

I wait until frost causes the foliage to yellow, brown and collapse before cleaning up my hostas.

So don’t assume an ugly hosta is ready to be cut down. Look at the leaves.

If they’re still mostly green, I wait.

5. Columbine

I’m also not cutting my columbine all the way to the ground just because it’s fall.

I’ll remove old flower stalks if necessary, along with foliage that is badly damaged or diseased.

But healthy green foliage can stay.

If your columbine is still green like mine, there’s no rush to cut the entire plant down.

This is another case where I’d rather watch what the plant is doing than automatically cut it back according to the calendar.

6. Black-Eyed Susan

I have Black-eyed Susan growing in this particular part of my garden, and it made this list for a very obvious reason.

It’s still flowering.

I’m certainly not going to cut down a perennial that is still producing flowers just because it’s fall.

Even after the flowers fade, there’s another reason not to rush.

Black-eyed Susan seed heads can be left standing to provide seeds for birds during the colder months. The dried stems can also provide winter habitat for insects.

I can always clean up the old growth in late winter or early spring before new growth begins.

Don’t Let the Calendar Decide When You Cut Back Your Garden

One of the biggest changes I’ve made to my fall garden cleanup is realizing that fall doesn’t automatically mean it’s time to cut everything down.

Before cutting back a perennial, I take a closer look at the plant.

Is the foliage still green? Is it still flowering? Does it have seed heads that birds might eat? Could the stems provide winter habitat? And could pruning now accidentally remove next year’s flower buds?

The answer will be different depending on the plant.

I’m not leaving my hydrangeas, astilbe, catmint, hostas, columbine and Black-eyed Susan alone for exactly the same reasons. Some may get cleaned up later once they go dormant, while others can stay standing through winter.

The important thing is that I’m not cutting them down simply because the calendar says it’s fall.

Sometimes one of the best things you can do during fall garden cleanup is leave the pruning shears in the shed and let the garden be a little messy.

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