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Pruning phlox in autumn: when is it worth pruning in autumn and when should you wait until spring?

With proper care summer-flowering flame flower can delight us with its magnificent flowers until autumn. But should you cut phlox after flowering in the fall, or wait for spring for pruning? We clarify.

Pruning phlox: When is the right time?

Should you cut Phlox paniculata in autumn

The flame flower (phlox) comes in different varieties. A distinction is made between annual and perennial species, low-growing and tall-growing growth forms and different flowering times. Therefore, it is impossible to talk about a uniform care, and the right time for pruning will depend on the species.

No pruning is necessary for annual species. Perennials and groundcovers, on the other hand, should be pruned regularly.

For example, tall-growing phlox is a remontant perennial. During the flowering season in summer, pruning the umbels that have not yet completely faded can lead to a second flowering. Thus, the flowering period is extended and you can enjoy the colorfulness of the plant until autumn. And what about after the second flowering in autumn? Should you cut the flame flower or leave the withered inflorescences? It depends on whether the phlox is early or late blooming.

Pruning is not necessary for cushion phlox because the plant retreats to the rootstock in the fall and its above-ground portion dies. The faded carpet pile is just pruned out in the fall. By pruning in early summer, the ground cover can be encouraged to bloom again. The shoots are shortened by one third.

Cut ground cover phlox or not

Is phlox hardy?

Most species of flame flower are hardy and perennial. The perennial phlox can withstand temperatures as low as -20 °C. This applies both to the creeping species, and to the high flame flower (Phlox paniculata). Do not forget to water the plant on frost-free days and protect it with fleece during heavy frost, and it will easily survive the winter.

When is autumn pruning of the flame flower useful?

Flame flower faded when to cut back

After the flowering period is over, the upper parts of the flame flower dry up. At this point, the amateur gardener wonders if he may cut off the withered shoots to give the garden a better look. This is certainly possible, cutting the plant back to a hand’s width above the ground. This works best for early blooming flame flowers, with pruning done in the fall. For perennials that bloom into the fall, it would make more sense to leave the withered shoots on the plant, as they function as a natural winter shelter. They also provide winter habitat for insects.

As a general rule, cut early-flowering phlox species in the fall, and late-flowering – just before new shoots appear in the spring.

Cut perennial phlox in the fall to create order in the garden.

Cut perennials in autumn

Dead perennials in the garden certainly no one likes. To create order in the bed, you can cut them in the fall. To ensure that your flame flower presents its bright blooms in the garden as early as possible next year, you need to schedule pruning in the fall before winter sets in.

Here’s how to do it correctly:

  • Gather the dried shoots into a bundle and bend them to the side.
  • Using a sharp knife or pruning shears, cut the stems about 10 inches above the ground.
  • Put the cut stems in the compost or use them as mulch for cold-sensitive plants (if they have no sign of infection, such as powdery mildew).

If the perennial has already formed seeds, you should collect them before cutting to avoid their spread. If you want to sow the seeds, store them in a cool and dry place and sow them in the spring.

Tip: If you want to prevent your flame flower from self-seeding, cut off the wilted flowers in the fall.

Prune flame flower and protect from powdery mildew.

Phlox can be in full bloom from late spring through the end of summer, but as temperatures cool, it fades. Another reason to cut back the perennial in late fall is powdery mildew . Phlox is susceptible to powdery mildew, especially if the foliage is wet for an extended period of time. Even powdery mildew-resistant varieties have a higher risk of infection during cool, wet fall months.

Tip: Destroy any foliage showing signs of powdery mildew and disinfect shears before pruning other plants.