How to Grow Sawtooth Sunflowers

Sawtooth sunflower plants

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Sunflowers have a way of making people smile. The sawtooth sunflower is no exception. These tall, shining yellow flowers are perennials that can be grown in many different zones. They are hardy and easy to care for.

What differentiates the sawtooth sunflower from other sunflower varieties is its red stems. Despite its name, its leaves are actually smooth or only slightly serrated. They are deep green, long, and sandpaper-like from the stiff hairs that cover the surface.

However, the star of the show isn’t the red stems or long leaves, but the bright yellow flowers that sit on top. They have both yellow ray florets, which are the large petals on the sunflower, and yellow disk florets, which are the centers of the flower. If you look closely at a sunflower, these centers are actually many tiny flowers. This is where their fertility comes from.

The sawtooth sunflower can vary widely in height. In large clusters, these flowers can grow up to five feet tall, while standalone flowers can be 12 feet.

Adding these cheery flowers to your garden can brighten up your late summer and fall with bright yellow blooms. They also attract many beneficial pollinators, such as bees and butterflies. When the flowers bloom, they also become natural bird feeders as they enjoy eating the seeds.

Botanical Name Helianthus grosseserratus
Common Name Sawtooth sunflower
Plant Type Perennial  
Mature Size 3 to 12 feet
Sun Exposure Full sun
Soil Type Rich, moist, and well-draining
Soil pH Neutral
Bloom Time Late summer to fall
Flower Color Yellow
Hardiness Zones 3 to 8, USA
Native Area United States and Canada

Sawtooth Sunflower Care

Growing sawtooth sunflowers is easy, and you are rewarded with one of the most eye-catching flowers around. Two key ingredients for big, healthy sunflowers are sunshine and water.

Light

As its name suggests, sawtooth sunflowers love lots of sunshine. Planting these flowers in an area that gets full sun for a large portion of the day will ensure the happiest flowers. At least six hours a day of direct sunlight is needed.

Sunflowers actually follow the sun through the sky as the day goes by, facing east in the morning, and west as the sun sets. Mature flowers may stay facing the east.

Soil

Sawtooth sunflowers prefer rich, moist soil full of organic material. However, they are hardy and can tolerate a variety of soil conditions just fine.

Giving it the ideal conditions will encourage a healthier and stronger plant. Be sure to give your sunflowers plenty of soil room. These plants can get very large and spread aggressively.

Water

Sunflowers love a good amount of water regularly, and sawtooth sunflowers are no exception.

If you forget to water them, don’t fret. This sunflower variety is very hardy and drought-resistant. They may droop, but a good watering will fix the problem quickly and you will have your sunflowers standing tall in no time. When watering, try to avoid soaking the leaves. This will help reduce the risk of different fungal diseases.

Temperature and Humidity

The sunflower isn’t only a happy, easy-going flower in looks, but in requirements as well. These flowers aren’t picky when it comes to temperature and humidity. They can thrive in any USDA hardiness zone between 3 and 8. Just be sure to give them plenty of water in the heat of summer.

Fertilizer

Going along with its easy care requirements, sunflowers don’t often need fertilizer. As long as your soil is good, adding organic material and compost will fulfil the needs of this flower. If you do have very poor soil and would like to add fertilizer, a 5-10-10 fertilizer should do nicely.

Propagating Sawtooth Sunflowers

Propagating sawtooth sunflowers is easy and can be done using cuttings, by dividing or from seed.

The sawtooth sunflower is an aggressive spreader and may make a small colony. In this case, you may want to divide the plants which grow through rhizomatous roots.

It is also possible to take cuttings in spring from this perennial sunflower. Select a cutting from a new, young stem that doesn't have any flowers on it. The bottom set of leaves should be removed and then the cutting should be rooted in a rich and moist soil in a lightly shaded position. Placing a bag over the cutting can also help it to root more quickly. Once it has taken root, the cutting should be slowly adjusted to longer periods of sunshine.

Growing Sawtooth Sunflowers From Seeds

You can plant your seeds in the fall to let them winter in the ground. These will pop out as soon as it is warm enough in the spring. Another way to start your sunflowers would be to start them inside a few weeks before you would plant them outside. Here’s how:

1. Using peat pots, plant your seeds in rich, moist soil 1/2” deep. Using these types of pots will make the transition from inside to the garden much easier on your sunflower and will avoid disturbing its root system.

2. Continue to keep the soil moist until germination occurs.

3. Once the threat of frost is gone and the weather is warmer, plant your seedlings and their peat pots directly into your garden.

Common Pests/Diseases

Sawtooth sunflowers can sometimes be bothered by weevils, beetles, grasshoppers, sunflower seed maggots, or sunflower aphids. Fungal problems on the leaves may also be an issue.