Updated at: 11-05-2022 - By: Sienna Lewis

Young sunflowers (Helianthus spp.) follow the sun as it passes overhead, their beautiful faces shining brightly. This characteristic lasts until the sunflowers are fully grown, whether they are in pots or in the garden. Zones 3 through 9 of the USDA Plant Hardiness Scale. Perennials that attract butterflies and birds in the fall and winter may also provide food and shelter for birds and other wildlife. Pinch back or prune sunflowers to lessen their size and form as needed to preserve healthy plants, abundance of flowers and seeds for humans, birds and wildlife.

Annual and Perennial Sunflowers

When it comes to sunflowers, there are both annual and perennial varieties that are produced for their beautiful blossoms. Nearly all of the 150 known species of sunflower are native to North America, according to the North Carolina Extension Gardener Plant Toolkit.

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The original weedy flowering annuals have spawned numerous varieties and hybrids, according to the Missouri Botanical Garden. Helianthus annuus ‘Elf’ and ‘Teddy Bear’ are dwarf cultivars that can grow up to 14 and 24 inches tall, respectively, while Helianthus annuus ‘American Giant,’ which can grow up to 10 feet tall, is a medium-sized cultivar that can grow up to 14 feet tall.

Helianthus angustifolius, Helianthus debilis, and Jerusalem artichoke are perennials (Helianthus tuberosus, zones 3 through 9). The beach sunflower, on the other hand, likes drier soils and can survive salty soils and salt spray better than the swamp sunflower and its cultivars. Despite the fact that Jerusalem artichoke can be invasive due to its spreading rhizomes and self-seeding nature, it is widely grown for its edible tubers and beautiful blossoms.

Planting and Caring for Sunflowers

A sunny, wind-sheltered, well-drained garden bed is ideal for growing sunflowers, even though they can thrive in a wide range of conditions. The Old Farmer’s Almanac recommends digging in 2 to 4 inches of compost and well-decomposed manure to a depth of 24 inches to accommodate the plants’ long taproots. Plant your sunflower seeds 1 inch deep when the soil temperature reaches 50 degrees Fahrenheit, and space them out according to the mature plant size: dwarf cultivars should be spaced 6 inches apart, while giant cultivars should be spaced 24 inches apart. Keep the soil uniformly moist until the seedlings appear in seven to ten days, then water thoroughly again.

A stake should be used to support taller varieties and multibranched sunflowers, according to Burpee. This will help support the stems as the heavy, seed-laden heads develop. Add a 2- to 4-inch layer of mulch around the plants pulled 4 inches away from the stems to slow evaporation of water from the soil. Water at the base of the plants and keep the foliage dry to help prevent fungal diseases, like powdery mildew.

Using stakes is recommended for varieties that reach a height of greater than 36 inches, as well as multibranched sunflowers. Helps the stems as heavy seed-laden heads are formed. It is important to have a 2- to 4-inch layer of mulch around your plants, around 4 inches from the stems of the plants. Powdery mildew can be prevented by watering the plants’ roots and keeping their foliage dry.

Consider the weather in your area. If you live in a climate where temperatures are above freezing, you should cut Maximillian, swamp, and willow-leaved (Helianthus salicifolius) sunflower plants down to two-thirds of their original height.

There is no longer a need to stake these prospective giants as a result of this new procedure.

After the first blossoms show, do not prune. During the middle and end of summer, the majority of perennial sunflower species bloom. Gardeners should keep a close check on their plants during these times and avoid pruning them once their buds begin to emerge.

There are some exceptions to this rule for cultivars with late summer blooms. Cut back late summer bloomers to 1.5 to 2 feet (0.5 to 0.6 m) in height because they will rebound and bloom within a few weeks no matter what you do.

June or July is a good time to cut back the tallest varieties of sunflowers. In June or July, trim Maximilian sunflowers (Helianthus maximiliani) and Mexican sunflowers (Tithonia diversifolia). As a result, the sunflowers’ height will be reduced from the customary 9 feet (2.7 m) to a more manageable 4 feet (1.2 m) (1.2 m).

For the birds, Maximilian sunflowers can be left standing all winter long. Even if you decide to let birds enjoy your tall sunflowers, you can prepare the plant for fresh growth by chopping them down in the spring.

You should be prepared for the fact that your annual flowers won’t bloom again in the near future. As soon as the annual sunflowers start turning brown, you can cut them down to the ground and dispose of them. Gardeners who know they won’t blossom again opt to remove them from their plots.

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All pruning tools should be sterilized before use. If you’ve recently handled with unhealthy plant parts, it’s very crucial to sterilize your trimming equipment. Bacteria and germs can’t be accidentally transferred over the garden this way.

Hand prune or use hedge shears to remove dead or diseased branches from sunflowers.

Trim the plant’s unhealthy sections first. Before beginning a major pruning operation, remove any diseased, weak, damaged, crossed, or dead branches from your plant.

To avoid the spread of the disease, diseased pieces should not be placed in the compost bin. Instead, it will be necessary to burn or bag these waste items and leave them for collection by municipal waste teams.

Perennials should be pruned to get the desired shape. When all of the diseased branches have been removed from your perennial sunflowers, you can choose to prune them for shape.

People who want their sunflowers to have a more natural appearance prune only the sections of the plant that have been injured.

After pruning your plants, give them a good watering. To help the sunflowers recuperate from the trauma of being clipped back, water them frequently. Every time the top inch of soil starts to dry out, give them enough water to completely wet it.

Trimming Sunflower Leaves and Stems

Sterilize your cutting instruments by soaking them in household cleaners like Lysol or Pine-Sol or rubbing alcohol before trimming or pruning sunflower plants. Let the blades dry naturally. Wear eye and skin protection gear including safety goggles, gloves, and long sleeve shirts to avoid getting scratched by the tough stems and sticky leaves.

During the spring and summer months, cut down perennial sunflowers by half to remove extra and unruly growth. To keep the plants bushy, pinch back the small annual cultivars. Once the flower buds start to form, don’t prune. When the flowers begin to fade, remove the stems to encourage the plant to produce more blooms. Make sure to get rid of any dead, dying, or infected leaves or stems as soon as possible.

After blooming, the annual sunflowers will not return. To put it another way, they will die. Rather than removing the dead stems right away, you can wait until the birds have eaten the seeds if you’re planning on keeping the seed heads out. As an alternative, leave the plant’s seed head in place where birds and other wildlife can get to it and then dig it up and dispose of it. Keeping the seeds for yourself, Harvest to Table recommends taking the seed head from the plant when the rear of its leaves begin to turn brown and then drying the seeds for a week before extracting them from the seed heads.

Things That You’ll Use

  • shears for trimming trees
  • Cleanser for the home or rubbing ethanol
  • Protective eyewear
  • Gloves for the garden

Why Do You Need To Prune Sunflowers

To be honest, if your sunflowers are annuals, you don’t really need to prune them. You shouldn’t have to do anything with these plants other than pick off the dead leaves as they fall off as they grow and flower.

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A little extra attention is required for perennial sunflowers, which grow up year after year and produce a significant amount of blossoms. To prevent them from bumping against one another and becoming damaged, a little trimming is in order.

Tools For Pruning Sunflowers

If you need to prune your sunflowers, a decent set of secateurs will come in handy. They’re comfortable in the hand and should be large enough to cut through even the thickest stems.

Sharp scissors can also be used for trimming plants, as the stems are often thin and don’t require a lot of slicing or decapitation. Invest in a pair of garden scissors so that your kitchen scissors don’t end up covered in sap!

When To Prune Sunflowers

You should prune your perennial sunflowers twice a year – cut them down to half their size in the beginning of summer, then reduce them by another third in late June or July. If you are growing one of the giant species, you should consider pruning them to 2/3rd of their size in June.

Final Words

Perennial sunflowers need to be pruned twice a year: once in early summer to half their growth, and again in late June or early July to reduce their size by another third. Prune a big species in June to a third of its original size if you’re growing it.