Should You Cut Astilbe Flowers Turning Brown? A Gardener’s Guide

As a gardener, I often face the dilemma of whether or not to cut back astilbe flowers once they start turning brown. Astilbe, with their fluffy, feather-like blooms, are a gorgeous addition to any garden. However, once those plumes begin fading, it can leave you wondering what to do next. Should you cut the spent flowers or leave them be? In this article, I’ll walk through the pros and cons to help you decide.

What Causes Astilbe Flowers to Turn Brown?

Before deciding whether or not to cut back browned astilbe blooms, it’s helpful to understand what causes them to fade in the first place There are a few key reasons astilbe flowers turn brown

• Natural aging Once astilbe is done blooming for the season, the flowers naturally begin to fade and dry out. This is a normal part of the plant’s lifecycle.

• Environmental stress. Factors like drought, extreme heat, or too much sun can cause astilbe blooms to brown prematurely

• Disease. Fungal diseases like powdery mildew can also lead to browned flowers.

So in many cases, minor browning is perfectly normal and not a cause for concern. However, if the fading seems excessive or is accompanied by other symptoms like wilting leaves, disease may be to blame.

The Case for Cutting Back Spent Blooms

Now that we know why astilbe flowers turn brown, let’s explore reasons you may want to cut them back:

• Improves appearance. Wilted, brown blooms can be an eyesore. Removing them makes way for fresh new growth.

• Encourages reblooming. Cutting spent stems back to the ground can promote a second wave of blooms on some astilbe varieties later in summer.

• Prevents disease spread. Getting rid of infected blooms helps limit the spread of fungal diseases to healthy parts of the plant.

• Promotes air circulation. Removing dense faded flowers allows more airflow around the plant, keeping foliage dry and less disease prone.

• Aids propagation. You can take healthy cuttings from spent flower stems to propagate new astilbe plants.

So in many cases, cutting back browned blooms offers clear benefits. Just be sure not to cut back healthy greenery along with spent flowers.

Reasons to Leave Faded Blooms

On the other hand, there are also good reasons you may opt to leave browning astilbe blooms in place:

• Natural appeal. The dried plumes retain an architectural, wispy beauty all their own.

• Wildlife appeal. Seed heads attract birds and provide winter interest.

• Protects new growth. Spent blooms shield developing foliage from sun scald and winter damage.

• Requires less work. Letting blooms fade on their own means less pruning for you.

• Avoids shock. Cutting back stems can shock the plant, especially if you cut too low into fresh foliage.

So depending on your gardening goals and style, leaving browned blooms also has its merits. It becomes a matter of personal preference.

Tips for Cutting Back Spent Astilbe Blooms

If you do choose to remove faded astilbe flowers, follow these tips for success:

• Time it right. Prune back blooms once they are completely spent, shriveled and brown. Don’t cut too early.

• Use clean, sharp pruners to avoid ripping or crushing stems.

• Cut back flower stems to the base, taking care not to damage fresh foliage.

• Remove damaged or diseased foliage as well.

• Disinfect tools before each cut to prevent disease spread.

• Add pruned stems to the compost pile or discard them.

• Water and mulch plants after pruning to reduce stress.

Alternative – Just Cutting Back Seed Heads

Here’s one compromise approach – leave the spent flower stems and plumes intact for their ornamental value, but snip off the seed heads. This eliminates messiness from self-sowing while keeping the plant’s architecture.

Monitor for Reblooming

Pay attention to see if your astilbe sends up any secondary blooms after cutting back flower stems. Varieties like ‘Fanal’ and ‘Sprite’ often rebloom, while others only bloom once. Knowing your plant’s habits will help inform whether pruning spent blooms is worthwhile.

Consider Staggered Bloom Times

One way to avoid having large swaths of faded flowers at once is to plant early, mid, and late season blooming astilbe varieties together. This provides a sequence of blooms so there are always some fresh flowers coming on.

In Summary

So in the end, whether to cut back spent astilbe blooms is a personal choice based on your garden’s needs. If faded flowers detract from the landscape or you want to encourage reblooming, pruning is likely worthwhile. But if you like the dried plumes or want to protect emerging growth, leaving them in place poses no harm. Just be sure to prune judiciously and properly care for plants afterward no matter what you decide. Paying attention to your astilbe’s growth habits will further inform the best approach. With a little trial and error, you’ll find the right balance for your unique garden.