Sunflowers are not only a popular plant-based on their looks, but they’re even good for the environment. This is because they have the ability to absorb radioactive materials and pollutants from within the soil. Beyond that, sunflowers are used to make sunflower oil, birdseed, or can be a tasty snack.
There are many benefits to growing sunflowers, but how does one take care of them? First, we must determine if you’re caring for sunflowers inside as a bouquet or outside in a garden.
Indoor Sunflower Care
Many people will send sunflowers in bouquets paired with roses, eucalyptus, or lavender because their vibrant color can really brighten someone’s day. However, once those sunflowers are delivered, how are they best cared for indoors?
Because sunflowers have naturally long and thick stems, which have heavily arched necks, they’re displayed best in a tall, narrow vase. After receiving or purchasing a sunflower bouquet, here are eight steps to properly care for them:
- Remove all leaves that fall below the water line in your vase.
- Hold the stems under water and cut off 2 to 3 cm (don’t let the cut stems dry out).
- Choose your vase, fill with water, and add the packet of flower conditioner/food that comes with the bouquet.
- Put the sunflowers in a vase that provides support for the full height of the flowers.
- After arranging, it’s suggested that you leave your arrangement in a cool, dark room where they can condition for a few hours.
- After the conditioning stage, flowers should be displayed in a cool area that’s out of direct sunlight because the temperature is an important factor in a sunflower’s life.
- As leaves die, you should remove them from the bouquet.
- Sunflowers need to be hydrated at all times because this helps them support their heavyweight.
When cared for correctly, sunflowers in a vase can last from six to twelve days. Another tip to keep your sunflower bouquets around longer is to look for flowers that are just beginning to stay fully open and that have straight, strong stems.
Outdoor Sunflower Care
When planting sunflowers outdoors, do note that these plants can grow very quickly and are known for resisting drought and disease very well. If you can protect your sunflowers from pests and wind, you’ll be on the right track to growing beautiful, long-lasting sunflowers wherever you choose to plant them.
Take note there’s more than one type of sunflower. In fact, there are three different variations of sunflowers:
- Classic yellow sunflowers: grow easily and quickly.
- Branching varieties: produce a lot of flowers per seed, but do so more slowly than classic sunflowers.
- Large varieties: an example is the mammoth sunflowers, which produce tastier seeds and can serve as a support for other climbing plants.
When planting sunflowers outdoors, you first need to decide which kind of sunflower you’ll be planting since they’ll require slightly different care plans.
Sunflowers will have the best luck growing in loamy soil (a mixture of sand, silt, and clay), that offers good drainage and a neutral pH. You’ll also want to choose a location that offers at least six to eight hours of sun per day.
Deciding when to plant your sunflowers is just as important as choosing where. The best time of the year to plant sunflowers is in the late spring, after the last frost has passed. Also, there are three varieties of times of day to plant sunflowers:
- Short-day: will need longer nights to trigger flowering. These sunflowers should be planted toward the end of summer.
- Long-day: will bloom in mid-summer.
- Day-neutral: can be planted any time.
When determining what time to plant your sunflowers, make sure to plan ahead based on when they’re expected to flower. The majority of sunflowers will bloom 60 days after planting, while some can take up to 90 days.
When planting your sunflower seeds, you want to plant them apart based on your desired flower size. This is important because the flowers will grow larger based on how far apart you space the seeds.
- For smaller, bouquet sized flowers, plant seeds 6 inches apart.
- For flowers with a maximum height above 5 feet, plant seeds at least 1foot apart from each other.
- For branching varieties, 18 inches of space is recommended between seeds.
Overall Sunflower Care
Now that your sunflower seeds are planted and seedlings are beginning to grow, here are some tips to help you care for your growing sunflowers:
- Water growing sunflowers daily. As seedlings, sunflowers require plenty of water in order to establish themselves.
The soil should be moist, but less than soaked, until their seedlings emerge from the soil. Typically, seedlings will emerge within 5-10 days of planting, but if the weather is cooler, this could take longer than that.
After the seedlings emerge, water them three to four inches from the plant as this will encourage root growth.
- Depending on what kind of soil your sunflowers are planted in, you may need to add slow-release fertilizer. While sunflowers, in general, don’t need fertilizer, if the soil is poor, adding a mixture of compost and fertilizer can help strengthen your plant.
- The most common pests to attack sunflowers are slugs and snails. One way to deter these pests from taking over your sunflowers is to surround the plants with slug repellent, which can be bought at any hardware/garden store.
- You should check daily for fungus on your sunflowers because downy mildew can attack sunflowers if not caught early on. Yellow leaves are the biggest indicator of this type of fungus. Thus, if the leaves are a bleached yellow color or are yellow with green veins, these can be signs of this fungus. Remove those leaves immediately.
- As sunflowers become mature, they require less water. After they develop a deep root, sunflowers become pretty drought-resistant, which is why, at this point, over-watering will do more damage than under-watering. When watering mature plants, try to avoid getting the blooms wet because this can be damaging to your plant.
- Lastly, if the weather is going to be severe, it’s best to tie your sunflowers to a sturdy support by using a cloth or another soft material.
Sunflowers, whether in a bouquet or in your yard, require fairly specific care. However, if properly taken care of, sunflowers have the ability to become hearty plants, either in a garden or as a beautiful centerpiece on your indoor table.
Sarah Eberle qualified and became a member of the Landscape Institute in 1980. Over the last 26 years she has practised landscape architecture and garden design, running her own business in Devon.
During the 1990s, Sarah joined Hillier Landscapes as Design Director, where she is still a shareholder but also runs her own practice in Hampshire.
Sarah has an esteemed record in RHS shows, having won eight Gold medals, Best in Show and the George Cook award for innovation twice at Hampton Court. Sarah has also exhibited at Tatton Park and BBC Gardeners’ World Live.