August and September are when sunflowers really hit their stride. The autumnal yellows, oranges, and russets of this iconic summer flower transition us from early summer's bright pinks and blues to the richer, jewel-like colors of fall.
Helianthus annus, the common annual sunflower, is one of about 70 species in the genus Helianthus, which also includes perennial sunflowers. An all-American annual, not only are sunflowers native to North and South Americas, they will grow in all 50 states.
In bud, young sunflowers turn their heads to follow the sun from east to west. This tendency to track the sun is called heliotropism. As they mature the flowers stay facing east.
Sunflowers are super easy to grow and have few pests or diseases. Growing them is a great way to get kids into gardening because they germinate quickly, plus the large seeds are easy for tiny hands to manage.
How to grow
Light: Like their name, sunflowers need full (8+ hours per day) sun.
Soil: The plants will grow in a variety of soil types, from clay to sandy, but will rot in soil that's consistently wet.
Planting: Plant when you would set out tomatoes, once the possibility of frost in your area is over. Sow seeds outdoors about six inches apart and an inch deep, or according to the instructions on the seed packet. Thin to 18 inches apart when they have four leaves. Sunflowers don't do as well when started indoors and transplanted.
Water: Sunflowers are prairie plants, accustomed to making the most of scant rainfall. That said, seedlings and young plants must have deep, consistent waterings as they develop the taproot that helps make them drought tolerant once they mature.
Care: If the soil is rich, sunflowers won't need fertilizing, but you can incorporate some compost when sowing, or feed with a diluted 5-10-10 organic fertilizer every few weeks. Deadhead multi-stemmed varieties to keep them blooming. Mulch isn't necessary, as the plant's leaves will shade out most weeds, though a two-inch cover of straw will help keep the soil from drying out too much.
The word "sunflower" conjures a vision of a tall stalk topped by a big flower with yellow petals and a large orange center disk. However, breeders have played with sunflower genetics to create dwarf varieties, growing from 1 to 4 feet tall, as well as varieties that can get as tall as 16 feet. There are double sunflowers, sunflowers that don't make seeds, and of course, sunflowers in colors from cream through russet red and even pink.
Tall varieties of sunflower usually send up a single stem with a single flower. The shorter the variety, the more likely it will branch and produce multiple flowers.
Red: 'Velvet Queen', 'Chianti', 'Ms. Mars'
Cream: 'Coconut Ice', 'Italian White', 'ProCut White Lite'
Bicolor: 'Candy Mountain Hybrid', 'Ring of Fire', 'Fire Catcher'
For seed: 'Mammoth', 'Super Snack Hybrid', 'Aztec Gold Hybrid'
Sunflowers are a favorite of just about every kind of wildlife, from deer and rabbits to bees, butterflies and birds. They are especially valuable to pollinators, especially bees. Many sunflower varieties popular with home gardeners yield nectar, but not pollen, and sunflower pollen is an important bee food. Good varieties for bees include 'Lemon Queen', 'Velvet Queen' and 'Mammoth'.
All articles are copyrighted and remain the property of the author.
By Justin Hancock, Monrovia Horticultural Craftsman
Photographs courtesy of Monrovia
Labor Day may represent summer’s unofficial close but now is a perfect opportunity to add late-summer perennials that will continue to beautify your landcare until fall arrives. click here for an article that identifies 9 perennials for late summer.
Click here to sign up for our monthly NEWSLETTER packed with great articles and helpful tips for your home, garden and pets!