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10 Best Tips On How To Grow And Take Care of Mammoth Sunflowers

The mammoth sunflowers, belonging to the famous family of sunflower cultivars, is an heirloom plant most commonly known for its incredible height.

While the overall plant can reach a massive height of about twelve feet, the flower itself reaches a height of approximately one foot.

Mammoth sunflowers are also renowned for their high-quality sunflower seeds and tolerance to lack of water.

 

How to Grow And Take Care of Mammoth Sunflowers

Despite their incredible height and giant flowerheads, mammoth sunflowers are very easy to grow and take care of. They can be grown in almost any kind of soil; however, loamy soil is the most preferred. It is best to water them every day initially for the first six weeks, after which the watering can be slowed down to two times per week. They require about six to eight hours of direct sunlight every day and can be grown after the last frost has passed. The ideal temperature is around 60 to 70 degrees Fahrenheit (15 to 21 degrees Celsius).

How to Grow And Take Care of Mammoth Sunflowers
How to Grow And Take Care of Mammoth Sunflowers

Although all kinds of sunflowers are native to North America, mammoth sunflowers gained popularity in Eastern Europe, where they were cultivated in great numbers by farmers.

Some of the countries where they are grown in abundance are Russia – because of which they are also known as Russian Giants or Russian Mammoths – Bulgaria, Moldova, Romania, and Ukraine.

Even today, they are largely grown in these countries, and many hybrid forms are now also being cultivated.

Ukraine today stands on the top in producing sunflower seeds which are a significant source of food for hungry birds.

To sustain their extraordinary length, these flowers have immensely strong stems which support the flowers during intense winds and in rainy seasons.

The flowers are enormous, with shiny, showy yellow petals and brown centers.

 

Mammoth Sunflowers Care Guide

 

Soil

When you are thinking of growing mammoth sunflowers in your garden, you will not have a hard time choosing the right type of soil – anything goes.

Ensure you don’t have too compact soil that allows the taproot to penetrate deep inside, and you are good to go with any kind of soil.

The soil you choose should have good drainage, so the water does not stay in it for a very long time.

As far as the pH of the soil is concerned, mammoth sunflowers prefer acidic to neutral soil with a pH ranging from 6.0 to 7.5.

 

Sunlight

Because mammoth sunflowers love sunlight, you will need to ensure that they are exposed to at least six hours of direct sunlight.

It would be ideal if the period of sunlight exposure could be further increased to eight hours per day.

However, to protect them from intense winds, you will also need to make sure that your mammoth sunflowers are in a sheltered location.

Due to this reason, finding the right spot where they get enough sunlight but are also affected by high winds can be pretty tricky.

If you do not expose the plant to a minimum of six hours of sunlight every day, your plant will have extremely stunted growth, the size of the flowers will not increase, and the overall strength of the plant will be compromised.

Mammoth sunflowers love sunlight, you will need to ensure that they are exposed to at least six hours of direct sunlight
Mammoth sunflowers love sunlight, you will need to ensure that they are exposed to at least six hours of direct sunlight

 

Water

The most critical period in which proper watering must be ensured is six weeks right after planting the seeds.

Because the plant is in its initial growth phase, it will require constant watering to grow strong roots. Make sure that the soil is well-draining and is constantly kept moist for the first six weeks after plantation.

However, look out for any signs of poor drainage or frozen soil. You can do this by observing how well the water seeps into the ground after watering.

If it does not go down fast enough or forms a pond on the surface of the soil, this indicates that your soil either does not have a sound drainage system or is still frozen.

While some gardeners do not water the plant at all after the six initial weeks have passed, it is still recommended to give the mammoth sunflowers a little water every week for their overall health.

Leaving the plant abandoned and not providing it with water for an extended period of time leads to stunted growth and poor quality of foliage.

Proper watering must be ensured is six weeks right after planting the sunflower seeds
Proper watering must be ensured is six weeks right after planting the sunflower seeds

 

Fertilizer

Because mammoth sunflowers are incredibly fast-growing plants, you will need to feed them with fertilizer every now and then so they can grow to their maximum potential.

To provide them with extra nutrients in the best way, it is recommended to treat the plant with composted manure.

However, if that is not available, you can also use a slow-release fertilizer. Make sure that you use fertilizers in their liquid form so that they can easily penetrate the soil and reach the roots of the plant. 

 

Temperature

If you want to grow mammoth sunflowers, the best time to do so is when the temperature is around 60 to 70 degrees Fahrenheit (15 to 21 degrees Celsius).

Typically, the ground will have this temperature about three to four weeks after the last frost.

 

Propagation

The best time to grow mammoth sunflowers is once the last frost has passed in your local area.

If you want to plant the seeds in the soil before this, you would be carrying a significant risk of damaging the sunflower seeds in freezing temperatures.

On the other hand, you can plant the seeds in mid-summer (June or July), but since the temperatures will cool down in the fall, your plant may not be able to achieve its great height before the cold hits.

The soil to be used in the propagation of mammoth sunflowers is no big deal since they can be grown in almost all kinds of soil.

However, loamy soil is a good option as it has a good drainage capacity. Make sure there is no debris around the area where you intend to plant your mammoth sunflowers.

The space should be clear of any weeds. Moreover, make sure that the location you have chosen gets plenty of direct sunlight every day.

Adding a little bit of organic compost to the soil will help enrich the quality and expedite the growth process.

Once the ground and the potting mix are settled, place the sunflower seeds about half an inch deep in the soil. Do not overcrowd the seed, each sunflower needs space of its own to grow.

The ideal spacing between the seeds should be about 18 to 24 inches. While this may seem a lot at first, you will thank us later.

Mammoth sunflowers sprout within a week or so. If you observe that multiple seedlings have sprouted from the same planting hole, you will need to thin them so that only the hardiest and the most robust stem grows.

Once the seedlings come up with at least two sets of leaves, cut one set from the bud.  

Propagation of mammoth sunflowers is no big deal since they can be grown in almost all kinds of soil
Propagation of mammoth sunflowers is no big deal since they can be grown in almost all kinds of soil

 

Harvesting Sunflowers Seeds

Sunflowers seeds are a great source of food not only for hungry insects and birds but also for humans who use these seeds as healthy snacks.

They can be eaten either raw or roasted, seasoned with a bit of black salt. If you do not want to eat these seeds, you can also save them for plantation in the next season.

It is time to harvest the plant when you see the head of the giant mammoth sunflower drooping and the color of the leaves turning from dark green to light yellow.

To harvest the sunflower seeds, you will first need to cut the head of the mammoth sunflower from the stem of the plant and lay it on a clean and dry surface.

You can also hang it somewhere with the help of a wire. Make sure that the cut head of the sunflower is not exposed to any insects or mice, as they will finish the seeds in seconds if given a chance.

Once the flower has dried completely, the seeds will automatically loosen up. Afterward, you can simply use your fingernails or a fork to detach the seeds from the center of the flower.

Rinse these seeds with warm water and place them on a clean surface to dry again. Once the seeds are dried up, you can store them in an air-tight container for up to three months.

Sunflowers seeds are a great source of food for humans who use these seeds as healthy snack
Sunflowers seeds are a great source of food for humans who use these seeds as healthy snack

 

Common Problems With Mammoth Sunflowers

 

Sunflower Moth

Although not highly destructive at first, sunflower moths are quite the damage-mongers. They are considered highly destructive because these moths lay eggs within the flowers.

Once these eggs hatch and larvae are formed, they feed themselves through the flowerheads, eventually leading to the death of their host.

Sunflower moths are quite the damage-mongers because these moths lay eggs within the flowers
Sunflower moths are quite the damage-mongers because these moths lay eggs within the flowers

 

Grasshoppers

Although grasshoppers are not a significant source of concern for the mammoth sunflower, they should be kept in check in case they increase in number.

An excessive amount of grasshoppers can quickly lead to defoliation of the plant.

 

Frequently Asked Questions About Mammoth Sunflowers

 

Do mammoth sunflowers need to be staked?

When it comes to planting your mammoth sunflowers, make sure that you give them enough space to avoid intertwining. A gap of at least 2 feet between each plant is necessary.

Moreover, you should plant these in a sheltered location where they get exposure to direct sunlight and are also safe from the intense winds.

 

Can I grow mammoth sunflowers in a pot?

Because mammoth sunflowers are large and may become congested in a small pot, you will need to grow them in a gallon pot.

If you don’t have a gallon pot, you can grow dwarf varieties of sunflowers in a small pot. It is essential to give mammoth sunflowers the space they need as you do not want them to become intertwined with each other.

 

How do you keep mammoth sunflowers maintained in good shape?

The most important thing to do when taking care of mammoth sunflowers is to keep them staked so that they can have their own separate space to thrive and not become tangled with each other.

Feed your flowers with potassium to encourage growth. Keep watering regularly, especially in dry seasons.

 

How to ensure that the sunflowers keep blooming?

A quick and easy trick to ensure that your sunflowers keep blooming every year is to cut their heads when the flower fades.

This is done to conserve the nutrients the dormant plant may be utilizing otherwise. Moreover, cutting the heads off also encourages new growth in the next season.

 

How fast do the mammoth sunflowers grow?

The best thing about mammoth sunflowers is that they grow very quickly and may need only about two to three whole months to reach their height of approximately twelve feet.

However, proper planting conditions such as the right kind of soil, strict watering schedule, and fertilizer must be maintained in order to expedite their growth.

Within the right environment, your sunflowers should be incredibly high within 90 to 120 days after planting.


 

Conclusion On How To Grow And Take Care of Mammoth Sunflowers

Mammoth Sunflowers are easy to care for and produce large, showy flowers. Choose loamy soil and make sure the sunflowers get at least 6-8 hours of direct sunlight each day. Plant once the last frost is over. The deal temperature range for mammoth sunflowers is 60 to 70 degrees Fahrenheit (15 to 21 degrees Celsius).

Author Bio

Daniel Iseli

Taking care of houseplants and gardening are my greatest passions. I am transforming my apartment into an urban jungle and am growing veggies in my indoor and outdoor garden year-round.