Cutting Back Black Eyed Susans – Flowering Season

What’s the need for cutting back black eyed susans? You may have found conflicting answers to this question, some say it’s winter, others say it’s after the flowering period. 

cutting back black eyed susans

In fact, both winter and flowering seasons are the time to prune this plant and the purposes are different too. 

During colder months, deadheading the plant gives it more chances of survival, since it is vulnerable to frost. Yet when it is flowering, pruning is a good measure to extend the blooming period.

In this article, we’ll delve into what to do with your black eyed Susan plants after they finish flowering, including tips on cutting them back, dividing them, and transplanting them if needed.

Cutting Back Black Eyed Susans For The Bloom: Pro Tips

cutting back black eyed susans

Unlike many other perennials, leaving the fading blooms on your black eyed Susan plants won’t impact their future performance or blooming cycle. 

While with other plants, leaving the blooms can drain resources, this is not the case with black eyed Susans. 

Therefore, the decision of when to cut them back ultimately comes down to personal preference.

Cutting Back Black Eyed Susans in the Fall

Cutting back black eyed Susans to the ground as soon as the flowers and stems begin to fade is a popular approach. 

Apart from keeping your flower beds neat and tidy, there are additional benefits to this method. 

cutting back black eyed susans

Control Pests

Cutting back in the fall helps protect the plants from disease, mildew, and pests. 

It prevents decaying foliage from becoming a breeding ground for diseases and a shelter for pests over the winter.

Control Growth

Black eyed Susans can be prolific self-seeders, spreading quickly and crowding out other perennials if not kept in check. 

By cutting the stems back as they fade, you can prevent your black eyed Susans from taking over your garden.

cutting back black eyed susans

Allowing Plants to Remain

With much benefits discussed by far, you should be aware that not cutting back black eyed susans also offer certain advantages. 

  • The seed heads of black eyed Susan plants provide a valuable food source for birds, especially when they dry on the stems during the cold winter months. 
  • Leaving the seed heads can result in more plants for the following year, as black eyed Susans can reseed easily and may be spread by wildlife.

Ultimately, whether you choose to cut back the flower stems or leave them for the birds, it’s up to your personal preference—just be cautious if mildew or disease is present in the fall.

cutting back black eyed susans

Dealing with Disease and Mildew

Black eyed Susans can sometimes become infected with mildew and disease as fall approaches, especially after a wet or cooler summer. 

To prevent the infection from recurring or spreading, it’s crucial to take action if you notice signs of mildew or disease.

Cut down any infected plants, including the foliage, stems, seed heads, and flowers. 

Remember: do not compost any diseased plants or foliage, as typical home composting bins do not reach the temperatures required to kill off the disease.

cutting back black eyed susans

Dividing and Transplanting Overgrown Plants

Why

In addition to self-seeding, black eyed Susan plants can also be divided and replanted as transplants. 

Dividing mature plants every three to five years helps maintain their health and encourage strong blooming. 

When the roots become overcrowded, the blooming cycles will become shorter and less vibrant, which is true for most perennials.

When

You can successfully divide black eyed Susans in both spring and fall, but fall is generally the better option.

Dividing in the fall allows you to assess which plants have outgrown their space.

Divide the plants as soon as their foliage begins to show signs of dying back, giving the new divisions ample time to establish in the soil before winter arrives.

cutting back black eyed susans

How

  1. To divide, start by cutting back the foliage close to the soil surface. This makes it easier to see and divide the plant. 
  2. Then, dig around the outer edges of the plant with a sharp shovel and lift it from the ground. 
  3. After lifting the plant, turn its roots over and divide them into equal sections. 
  4. The size of the divisions will determine the size of next year’s plants. 
  5. Transplant the new divisions into fresh planting holes, amending each hole with compost to aid establishment. 
  6. Water the new divisions every few days to help them re-establish.

Mulching and Overwintering

cutting back black eyed susans

To protect new transplants through the winter, mulch them with a few inches of fresh mulch. 

Depending on the autumn temperatures, you may observe new growth emerging from the base of the transplants. 

Don’t worry—this growth won’t harm the plants. The foliage will wither away when the first freeze or heavy frost hits. 

Come springtime, your black eyed Susans will be ready to flourish. As black eyed Susans are low-maintenance plants, fertilization is not necessary.