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How to Prune Sunflowers – 4 Amazing Tips

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Helianthus annuus, commonly known as sunflowers, is a perennial flowering plant belonging to the daisy family. Sunflowers bloom annually in the mid-summer to the early fall season. Sunflowers are known for their bright yellow flowers that resemble the sun.

Nothing says Happy Summer like the bright, cheerful, yellow flowers of a sunflower! It is the perfect flower to add to your plant collection. Sunflowers are easy-going and low maintenance, and they can bring a whole different level of summer sweetness to your garden.

Sunflowers are heliotropic flowers which means that they move with the sun’s movement. Sunflowers face the sun in the East and keep moving from East to West following the sun. They face the eastside again at night, just ready to face the sun the next morning!

If you want to brighten up your yard and plant some sunflowers, then you can buy them here. And if you already have these lovely flowers and need help with their maintenance, then we are here to teach you how to prune sunflowers.

How to Prune Sunflowers
via Pixabay

Why Should you Prune the Sunflowers?

Sunflowers can grow very tall, and they have pretty large stems. When sunflowers grow together in larger groups, their tall stalks can knock out each other or even get entangled. Large stems also lack support. Hence, the flowers droop down.

They can need pruning once or twice every year to maintain them and keep them nice and tidy. If the sunflowers are not pruned, they look very unruly and bring down the charm of their lovely flowers. Pruning also helps get rid of dead or dying flowers, leaves, and stems and allows the growth of a healthy plant.

When Should You Prune the Sunflowers?

Knowing the right time to prune your sunflowers is critically important. The following tips will help you understand when and how much pruning your sunflowers need.

1.     Prune Perennials Twice Annually

A good rule for the common perennial sunflower plants is to prune them twice a year. Cut the sunflowers half in size in late spring or early summer. Then prune them again by cutting them to a third of their size during June and July.

2.     Do Not Prune After First Bloom

Most of the perennial sunflowers bloom somewhere between mid to late summer. Keep an eye out for the first bloom and avoid pruning the plants when the buds start to appear.

However, if you have the late-blooming variety of sunflowers, then prune them when they reach the height of 1.5 to 2 feet. These varieties grow much quicker, often within a week, and they can still bloom even after pruning.

3.     Pruning the Tall Variety of Sunflowers

It would help if you trimmed the tall variety of sunflowers known as Maximilian during June and July. It will help you reduce the size of these tall giants from 9 feet to a more easily manageable size of 4 feet.

If you want to leave your sunflowers tall in the winter months for the birds to feed on their seeds, then you can cut them to the ground in spring. They will be ready to grow new plants in the summer months and bloom again.

4.     Annual Blossoms

It would help if you kept in mind that the annual blossoms bloom only once a year, and then they never bloom again. You can prune them to the ground after their blooming season is over.

Some gardeners prefer to remove the whole plant from the ground after the flowers bloom.

Step-by-Step Instructions on How to Prune Sunflowers

After learning everything about the timing and frequency of pruning your sunflowers, it’s time to dive into how to prune sunflowers.

Required Items

  • Pruning Shears/ Hedge Trimmer
  • Sharp Bypass Hand Pruners
  • Gloves
  • Water
  • Rubbing Alcohol

Step 1: Sterilize Your Gardening Tools

Take some rubbing alcohol, disinfectant, or any household cleaning agent and clean your gardening tools thoroughly.

This step is important because if you don’t clean your shears, there is a chance to spread diseases in your plants, especially if you have cut a diseased plant with the same shears before. It is also important to eliminate any bacteria to avoid any infectious diseases in your freshly cut plants.

Step 2: Start by Trimming the Unhealthy Parts

Before trimming, take a pair of sharp scissors and trim down the damaged, diseased, dying, weak and unhealthy parts first.

Put these parts separately and do not put them in the compost bin because they may also spread diseases to other plants. Keep all the damaged parts in a bag that must be burned or collected and disposed of by the local waste collectors.

Step 3: Prune Your Sunflowers in Desired Length

Now that you have cut all the damages and unhealthy bits, it’s time to prune the plant. Take your shears or bypass hand pruners and cut the sunflower stems in desired shapes and sizes.

Step 4: Give Them a Drink!

Once you have pruned your sunflowers, please give them a generous amount of water to help them recover from the shock of cutting. Water will also help the plants absorb nutrients from the soil for fast recovery and healthy growth. Water your plants every time the first inch of the soil appears to be dry.

Additional Tips for Sunflowers

  • Sunflower plants require regular watering but do not overwater your plant as it may cause the flowers to rot and for new diseases to occur.
  • If you are growing sunflowers to harvest seeds, it is important to protect the seeds from birds and animals. For that, you can put some cheesecloth or paper bags over the flowers once the petals have fallen to protect the seeds.
  • Pull out the weed from around the plants by hand, especially when the new seedlings grow. The weed can take away essential nutrients from the growing plant, which may halt their growth and spread diseases.
  • Annual sunflowers do not require fertilization, but it is necessary to fertilize your perennial sunflowers to ensure healthy growth.
  • Cut off the flowers of perennial sunflowers as soon as they wilt and cut some leaves and topmost stem with it. Deadheading encourages the growth of more blooms.
  • While watering the sunflower plant, avoid wetting the leaves. Wet foliage is susceptible to mildew and other fungal infections.
  • When the cold has killed the sunflowers during the fall, deadhead the plants and then spread 2 inches of mulch all over the soil around the plants. Mulch will keep the soil insulated during the cold winter season and protect the plant’s roots.
  • Sunflowers that grow over 3 feet tall can flop down or even snap under the weight of their flowers. They may also break in harsh summer winds and rain. You can use stakes to support your stalks and prevent them from breaking. Loosely tie your stem to a stake using a twine.


Nothing speaks summer as the sunflower plants. Their bright yellow flowers are just what you need to cheer your mood during a warm summer day. To enjoy this blissful sight, you need to control your unruly sunflowers.

For that purpose, we have taught you how to prune sunflowers so you can enjoy them to your heart’s fill. Share your amazing sunflower stories with us in the comments.