Sunflowers are amazing but you may be wondering just how finicky they may be. Is this one of those plants that need a lot of TLC to survive and thrive, or are they tough and can manage pretty much on their own? We have searched the internet to figure out just how hardy sunflowers are, to get you all the answers you need!
Sunflowers are considered to be very hardy plants. They are heat and drought-tolerant and perennial varieties can come back year after year. In fact, sunflowers are not only beautiful, useful, and prolific but they also help clean contaminants from the soil. They have even been used to help clean up radioactive sites like Chernobyl and Fukushima. Sunflowers even do well as wildflowers and varieties such as swamp sunflowers can be seen growing along roads or vacant lots. That's one hardy plant!
Let's take a closer look at specifically how sunflowers are hardy and what they are tolerant of.
Are Sunflowers Heat Tolerant?
Yes, sunflowers are heat tolerant and actually prefer warmer weather. Most varieties thrive in USDA hardiness zones 4 to 9. However, they can be grown in the cooler parts of the year in hotter hardiness zones.
As far as weather is concerned, the wind is the primary danger to sunflowers, especially the tall-growing varieties.
If you live in an area with lots of fast wind but want to grow tall sunflowers, consider picking a variety of sunflower that has a thick, strong stem. Varieties to consider include Soraya and Suntastic. Support stakes and shelter are other good ways to help keep the wind from catching the sunflowers and damaging the plants.
If you are growing an especially tall variety of sunflowers such as the Russian Mammoth, it may be hard to find a commercial stake that supports the entire plant. A partial support stake is still helpful in supporting the plants' base. Another good idea is to give them some support and shelter by growing them next to a fence or other structure.
Are Sunflowers Drought Resistant?
In short, yes sunflowers are drought resistant. Sunflowers have roots that can grow very deep in the soil so they do not generally need a ton of extra watering once they are established. Regardless, like all plants, sunflowers need water to grow and live.
If sunflowers do not get enough water their growth may slow and they will likely have fewer and smaller blooms. Sunflowers also need to be watered occasionally when they are young and beginning to establish their root systems.
Are Sunflowers Disease Resistant?
Compared to most other plants, sunflowers are fairly disease resistant as there are not too many diseases that plague them. Because of this, when growing small amounts of sunflowers, most gardeners do not usually have to worry about diseases doing much damage to their plants.
Common diseases in sunflowers include powdery and downy mildew, Alternaria and head, or stalk rot. Fungal diseases like powdery mildew, are particularly annoying to gardeners because they usually damage the look of the plant. However, they are usually easy to fix by changing watering practices or airflow.
As far as disease resistance is concerned, some varieties are resistant to specific diseases. For example, ProCut Orange DMR is resistant to downy mildew. When purchasing seeds, take a look at the seed packet to see if any particular disease resistances are listed.
If you are concerned about diseases in general, look into varieties like Vincent's Choice, Ring of Fire, Russian Mammoth, and Teddy Bear.
Are Sunflowers Pest Resistant?
Unfortunately, no, sunflowers are not pest resistant. The seeds are full of protein and other nutrients so humans are not the only ones who like to eat sunflower seeds. Pests such as birds, squirrels, rabbits, and deer love to munch on sunflowers.
Unfortunately, pests do not exclusively eat the seeds, so they are a risk to sunflowers throughout their growing cycle. However, as long as the plant is not too heavily damaged, sunflowers can bounce back from having leaves eaten pretty easily. Since they only flower during the end of their life cycle, sunflowers will not repair or replace damaged flower petals.
Smaller pests, such as rabbits and squirrels do not damage sunflowers enough to permanently impair their growth. However, it may slow their growth speed. Plants need leaves to photosynthesize, so if their leaves are damaged they cannot generally produce necessary nutrients as quickly or as well.
Larger pests such as deer are a bit more of a worry as they can do a lot of long term damage to sunflowers. Not only can deer eat a large portion of sunflowers but they can also stomp and otherwise permanently destroy sunflowers. For more information on if Sunflowers are deer resistant and how you can defend against pests, check out this article.
Another not-so-annoying "pest" that can eat sunflowers is humans. Sunflower leaves are especially common for salads and sunflowers are a very popular microgreen. Humans can actually eat every part of sunflowers, roots, flowers, and all!
Do Sunflowers Need a Lot of Sun?
Sunflowers, as the name suggests, need a fair bit of sun. Around six hours a day is the minimum amount of sun sunflowers need to survive. However, if you are trying to grow your sunflowers to be larger or extra prolific, more sun is better.
Sunflowers are heliotropic, so they will follow the sun and soak up as much of it as they can. The more sun your sunflowers get, the bigger and better blooms they can produce. Because of this, it can be difficult to grow sunflowers indoors.
If you live in a shady area or would like to take on the challenge of growing sunflowers indoors, consider a more shade-tolerant variety. Helianthus divaricatus, the woodland sunflower, is a common example of such a variety. They can grow in shady areas but grow bushier and shorter than most sunflowers. Still, they have beautiful blooms that make wonderful cut flowers.
Can Sunflowers Survive the Winter?
While sunflowers can survive the winter and grow next year, most will not. Weather is a big variable with this.
Sunflowers planted indoors, in containers or in otherwise climate-controlled locations have a much higher survival rate than sunflowers just planted in the bare soil. Some varieties that do well in containers include Elf, Pacino, Bashful, and Suntastic Yellow sunflowers.
It is still important to be aware that going to seed and dying is a natural part of most sunflowers' life cycle.
If you live in a compatible zone, you can plant new sunflowers in winter or late fall and enjoy their blooms in the winter. However, your weather and variety of sunflowers have heavy influences on if that is possible. Because of the decreased amount of sun in some areas, sunflowers growing in winter may not be as productive or flower as boldly.
You can let the sunflowers naturally drop their seeds when they die off and enjoy new sunflowers again the next year. Be aware that the flowers may need to be thinned depending on the space they are in.
One of the best and easiest ways to get sunflowers to bloom again next year is to pick a perennial variety. If you are curious if your sunflowers will grow back or not next year, check out this informative article.
If you are interested in learning more about sunflowers, check out these other wonderful and informational articles.