A few weeks ago I published an article with the 14 perennials that you should prune this fall. It was a SUCCESS! My readers loved it!

So, given the success of that article, I decided to make another list, this time of the annuals that you should prune this fall, so that they continue to bloom like never before!

It may seem a little “drastic” to prune your annuals, but the truth is that it is a necessary “evil” so that they continue to bloom. Cutting them back helps tidy up your garden, prevents disease, and, for some plants, lets you collect seeds for next year.

Zinnias
Zinnias

Snip off spent flowers and any leggy or diseased stems using clean, sharp pruners. You can cut them down to about 6 inches from the ground. If you’re collecting seeds, let some flowers go to seed before cutting them back.

  • When to Cut Back: After the first frost or when they’ve finished blooming.

Cut marigolds back to about 6-8 inches from the ground. Remove dead flowers and stems to encourage any last-minute blooms before the frost hits.

  • When to Cut Back: Early to mid-fall when they start to look ragged or after blooming stops.
Petunias
Petunias

Petunias can get leggy, so trim them by cutting back long stems by half to promote more flowers. In the fall, cut them down to the base to clean up the garden.

  • When to Cut Back: Late summer to early fall, when growth starts to slow.

Use scissors or pruners to cut impatiens back by about one-third to encourage bushier growth. In the fall, you can pull out the whole plant after it dies back from frost.

  • When to Cut Back: In late summer, after flowering slows.
Cosmos
Cosmos

For cosmos, deadhead spent flowers throughout the season to encourage more blooms. Once the flowers stop, cut the plants down to ground level.

  • When to Cut Back: After flowering finishes, typically in early to mid-fall.

Trim back by one-third, focusing on removing dead or diseased stems. If overwintering, cut down to about 6-8 inches and store in a cool, dark place.

  • When to Cut Back: After the first frost or if you plan to overwinter them, before bringing them indoors.
Sunflowers
Sunflowers

Once the sunflower heads droop and the petals have fallen, cut back the stem to ground level. If you want to harvest the seeds, wait until the back of the flower head turns brown before cutting.

  • When to Cut Back: Late fall, after the blooms are spent and seeds have formed.

Trim spent flowers throughout the growing season. In the fall, cut the entire plant down to about 6 inches above the ground for a clean finish.

  • When to Cut Back: In early to mid-fall, after the blooms fade.
Snapdragon
Snapdragon

Cut back snapdragons to about one-third of their height to encourage fall blooms. Once the season is over, cut the plant to ground level.

  • When to Cut Back: After they stop blooming in late summer or early fall.

Nasturtiums can be cut back to the ground when frost kills them off. You can also trim them lightly throughout the season to encourage a bushier growth habit.

  • When to Cut Back: In late fall after the first frost.
Begonias
Begonias

Cut back begonias to about 3 inches above the soil. If you plan to bring them indoors, this trimming will help with a tidy overwintering process.

  • When to Cut Back: Before the first frost, especially if overwintering.
Prunning
  • Timing is key: Aim to cut back your annuals before the first hard frost but after they’ve finished blooming.
  • Use sharp, clean tools to prevent disease.
  • Be mindful of seed collection. If you want to save seeds for next year, leave some flowers on the plants until they dry out.

By cutting back your annuals, you’re helping to keep your garden healthy and ready for the next season.

Plus, it makes for a tidy garden that’s easier to manage when spring rolls around! Happy gardening!

11 Annuals You Must Cut Back This Fall (and How to Do It Right)

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