UT Gardens’ July Plant of the Month
Submitted by Camille Newsom, research coordinator at UT Gardens, Jackson
KNOXVILLE, Tenn. – What is your favorite flower? One common answer is the sunflower (Helianthus annuus). Although they are popular for commercial bouquets, some might not realize how easy they are to grow from seed.
Sunflowers are native to much of North America. They are an important agriculture crop with more than 1 million acres grown in the United States each year, primarily for oil and bird seed. The seeds are inexpensive and easy to find at garden centers and in seed catalogues. Plant breeders have developed varieties in a wide range of colors, patterns and sizes. They can be white, green, pink, yellow, orange, red, bronze or brown with heights ranging from a mere 20 inches tall up to 20 feet or more. A few favorites include ‘Autumn Beauty’, ‘Concert Bell’, ‘Earth Walker’ and ‘Mammoth’. Some sunflowers branch, producing many flowers on each plant and others put their energy into producing one single large flower.
Not only are sunflowers a favorite of many people but they are also popular with wildlife. Watch one for a few minutes, and you will see bees, butterflies and other insects that drink nectar and gather pollen. After pollination, the petals dry up, the flowerheads hang down and seeds mature. If left intact, these will attract birds like goldfinch, titmice and chickadees to the garden. Collect some of the seeds, and you can keep growing them for years to come. To ensure ample pollen and fertile seed production, be sure to choose “open pollinated” varieties. Many hybridized introductions are pollenless and sterile to accommodate the cut flower industry.
In Tennessee, sunflowers can be grown from May through October as long as it is frost free. Seeds can be directly sown in the ground or started in containers and carefully transplanted once their true leaves emerge. When starting seeds in the ground, it’s a good idea to plant the seeds 1-2 inches deep in loose soil and cover the planting area with something that will keep the birds and squirrels from digging them up. Sunflowers grow best in full sun and thrive in poor to average garden soil. They are drought tolerant once established but perform their best with regular watering. Planting in succession, about every two weeks, will give you continuous blooms. Taller varieties may benefit from staking if planted in areas exposed to a lot of wind, but most are strong enough to stand on their own. Seed grown sunflowers are great for beginners and experienced gardeners alike. You can find them growing at UT Gardens in Jackson and in the Knoxville kitchen garden and trial beds, typically in bloom July-August.
The UT Gardens includes plant collections located in Knoxville, Crossville and Jackson, Tennessee. Designated as the official botanical garden for the State of Tennessee, the UT Gardens are part of the UT Institute of Agriculture. The Gardens’ mission is to foster appreciation, education and stewardship of plants through garden displays, educational programs and research trials. The Gardens are open during all seasons and free to the public. For more information, see the Gardens website: utgardens.tennessee.edu.
The University of Tennessee Institute of Agriculture is comprised of the Herbert College of Agriculture, UT College of Veterinary Medicine, UT AgResearch and UT Extension. Through its land-grant mission of teaching, research and outreach, the Institute touches lives and provides Real. Life. Solutions. to Tennesseans and beyond. utia.tennessee.edu.