Plant of the Week - Sunflower
Annual grown from seed 90-110 days to maturity
A garden wouldn't seem like a garden without the radiance of this beloved flower. The sunflower comes by its name simply, with "helios" meaning "sun" and "anthos" meaning "flowers." It is a member of the aster family and there are over 70 species of this herbaceous plant.
Not only does this flower resemble the sun's shape and color, but the flower is “heliotropic” - meaning it actually turns to face and track the sun as it moves from east to west. I just love this part, but hold up! Even more cool is that this globally famous flower got its humble beginnings in the deserts of North and South America.
Something we can really claim as our own! Long grown by American Indians living in the Four Corners area, the wild sunflower has been traced back to seeds found in our Arizona clay soil dating back nearly 3,000 BCE. In the beginning, long before beans and corn became staples, American Indians had sunflowers. They ate the seeds, ground the kernels into flour, extracted the oil for their hair and used the pollen to make dyes.
The head of a sunflowers can consist of over 2,000 tiny florets that turn into seeds after pollination. The tallest sunflower grown to date was in 2014 by German gardener Hans-Peter Schiffer towering over 30 feet!
Amazed by their statuesque growth, children are easily drawn into the garden by big, cheerful, fast-growing sunflowers. Help your kids create a sunflower playhouse by planting the seeds in the shape of a square or circle, leaving an opening for a door.
The joy of sunflowers is to grow them, so go for it! It is such bliss watching their amazing journey from seed to flower making it the most fun, easy and rewarding flowers to grow in the garden!
Growing guide: Full sun exposure
Sunflowers grow very well here in the low desert. You can plant them from seed February through July!
They’re hardy and do well in most any exposure - even in the full west sun. That’s a big YIPPEE for us in the low desert. Anytime we find something that can grow in the hot west exposure is a time for celebration.
Sunflowers have long tap roots and are heavy feeders, so you need to prepare your native soil for annual/perennial planting amending with at least 1-3” of compost, earthworm castings and kelp meal. If planting direct into native Phoenix soil, adding gypsum will help to loosen it up for the roots to travel easily through our heavy clay soil structure.
Sow and space your seeds/rows according to the seed packet. Typically, the larger seeds go down 1” into the soil, rows 24” apart and plants 12” apart. I usually plant more seeds than prescribed and thin them as they begin to mature so they can reach their full flowering potential.
You can keep planting seeds every couple of weeks to ensure a long-lasting show of flowers well through summer.
Plant tall varieties near a wall or fence, or place sturdy supports to prevent monsoon winds from blowing down the giant stalks.
Water regularly, providing deep irrigation, and in the hot summer, add a 2-inch to 3-inch layer of mulch (straw, compost or wood shavings) to keep the soil moist and cool.
Fertilizing might not be necessary if you've prepared the soil well, and note that if you over fertilize, you'll get more leaf growth than flowers.
Keep your plants free of disease by watering at soil level (not wetting foliage), mulching and keeping them spaced sufficiently to allow air to circulate around the plants.
Trim off any diseased leaves quickly, and pick up any that may have fallen on the ground.
As seed heads develop, cover them with cheesecloth or mesh to protect them from birds - unless you want to share with them.
Leslie’s Tips: Sunflower hues range from pinkish reds to burnt oranges to deep bronze scarlets. Here are some varieties to grow:
*note the growing guide applies to gardening in the Phoenix Metro low or subtropical desert with minimum temperatures of 25-30º F and 151-180 days with temps above 86º F. USDA Hardiness Zone 9b, Sunset Climate Zone 13 and AHS Heat Zone 10.
** any reference as to how the plant is used medicinally are for historical purposes only. Always consult your physician or primary care provider, before ingesting any plant parts or by products.