How to Prune Million Bells

Calibrachoa parviflora

Reviewed by Kiersten Rankel M.S.

Quick Answer

Million Bells blooms continuously from spring through frost and benefits most from a mid-season trim in midsummer when stems get leggy. Cut the whole plant back by one-third, just above a set of leaves, and it will flush out with a new round of flowers within two to three weeks. Deadheading individual flowers is unnecessary since the plant drops them naturally, but trimming the whole plant once or twice a season keeps it bushy and floriferous.

When is the best time to prune?

As an annual grown primarily for a single season of bloom, Million Bells is trimmed based on when stems start to stretch and thin, which happens earlier in hot-summer regions than in cooler coastal areas.

Pacific

Jun–Aug

Mountain

Jun–Jul

Midwest

Jun–Jul

Northeast

Jun–Jul

Southeast

May–Jun

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Why Should I Prune My Million Bells?

Million Bells is a heavy bloomer that can wear itself out by midsummer. The stems stretch and thin, flowers get smaller, and the whole plant looks sparse and floppy. A quick trim refreshes everything.

The good news is that pruning Million Bells is forgiving. Unlike some plants where cut timing is critical, you can trim Million Bells almost any time the plant looks leggy, as long as you are still within the growing season. The only rule is to leave several sets of leaves on each stem so the plant has energy to rebound.

Cut the entire plant back by about one-third, making cuts just above a leaf node where two leaves attach to the stem. Within two to three weeks, new branching stems with fresh flowers will fill in from each cut point.

You do not need to deadhead individual spent flowers. Million Bells drops them on its own. Focus your effort on the once or twice a season trim rather than picking off tiny spent blooms.

Know Before You Cut

Difficulty Easy

Max removal 1/3 of stem length per trim

Growth pattern Trailing annual

Tools Sharp scissors or pruners

What Should I Remove?

Trim all stems back by one-third when the plant looks leggy

Cut just above a leaf node on each stem

Repeat once more later in summer if needed

Don't try to deadhead individual tiny flowers

Don't cut stems back to bare stem with no leaves

Don't skip trimming if the plant looks sparse and stretched

How Do I Prune Step by Step?

Watch for the signal to trim

When you notice the stems have stretched several inches, flower size has decreased, and the plant looks thin or bare toward the center, it is time for a trim.

Cut all stems back by one-third

Working across the whole plant, cut each stem back to about two-thirds of its current length, making the cut just above a pair or set of leaves.

Remove any dead or brown stems entirely

If you find any stems that are brown all the way through with no green growth, cut those back to where they meet a healthy stem or the base of the plant.

Water and feed after trimming

After a trim, water thoroughly and apply a balanced liquid fertilizer. This gives the plant the resources it needs to push the next flush of branching growth and flowers.

Got More Questions?

Do I need to deadhead Million Bells?

No. Million Bells is self-cleaning, meaning it drops spent flowers on its own. You get much better results from a whole-plant trim once or twice a season than from trying to remove individual spent blooms.

My Million Bells was beautiful in spring but looks awful now. Is it too late to trim it?

As long as there is still growing season ahead and temperatures have not dropped to frost, trim it back by one-third. It will bounce back. Even a late-summer trim can give you several more weeks of good bloom.

Can Million Bells survive winter and bloom again next year?

In zones 9-11 it can overwinter as a perennial. In most of North America it is grown as an annual and will be killed by frost. If you are in a frost-free zone, cut it back hard in late fall and it will regrow in spring.

How do I know if I cut Million Bells back too far?

If you left at least two or three sets of leaves on each stem, the plant will recover. If stems were cut all the way back to bare stem with no leaves, recovery is much less certain. Aim to always leave some leaves on every stem.

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About This Article

Kiersten Rankel M.S.

Botanical Data Lead at Greg · Plant Scientist

About the Author

Kiersten Rankel holds an M.S. in Ecology & Evolutionary Biology from Tulane University. A certified Louisiana Master Naturalist, she has over a decade of experience in science communication, with research spanning corals, cypress trees, marsh grasses, and more. At Greg, she curates species data and verifies care recommendations against botanical research.

See Kiersten Rankel's full background on LinkedIn.

Editorial Process

Pruning guidance verified against Calibrachoa parviflora growth data from Greg's botanical database, cross-referenced with USDA hardiness zone data and published horticultural research.

4,146+ Greg users growing this plant

USDA hardiness zones 9a–11b

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