In my opinion, the happy-face of the plant world is a big, beautiful, yellow sunflower. They can be grown as a cash crop for their edible seeds and oil or for the sunshine they add to a floral arrangement.
Sunflowers (Helianthus annuus) grow rather rapidly, producing large, rough leaves and seed-laden heads. The yellow petals that you see around the outside of the head are ray petals, attracting pollinators to the disk and the face of the head actually contains hundreds of disk flowers, each of which will form a seed. Sunflower heads turn with or track the sun during the early stages of their development. This aids in light exposure and photosynthesis. After pollination the disk will remain east-facing and eventually turn downward to protect the seeds from solar radiation.
Seeds may be planted about one to two inches deep after the soil has reached a temperature of 50-60 degrees and all danger of frost has passed, through mid-July. Sunflowers prefer well-drained, sandy loam soil and six to eight hours of direct sunlight. Depending on the variety, sunflowers mature and develop seeds in 80-120 days. Sow a new row every few weeks to provide continuous blooms until the first frost.
While the shorter varieties will not require staking, it is helpful to provide support for those that grow more than three feet tall or are multi-branched. Plants that are shallow rooted and weighed down with heavy flower heads are vulnerable to summer storms with wind and rain.
I have not had much of a problem with diseases or insects. Grasshoppers and caterpillars like to feed on the leaves but not so much that it has been detrimental to the plant or yield. As with everything else in the garden, good crop rotation will prevent problems with sunflowers.
If you are not going to use the seeds, it is fun to watch wildlife enjoy the bounty. But if you do want to save them, protect the seed from birds by covering the head with burlap or netting. Sunflower seeds are considered mature when the back of the seed head is yellow. Remove the entire head and place it in a bag or wrap it in cheesecloth and hang it in a cool, dry, dark area to finish drying.
After about two weeks the seed should be ready for eating. The birds like them raw but I like them roasted with a little salt. Arrange the dried seeds in a shallow pan and roast them at 300 degrees for 30-40 minutes.
There are so many different varieties and colors of sunflowers to choose from. Start planting today and bring a little sunshine to your life!
As always, Happy Gardening!
The Purdue University Cooperative Extension Service can be reached at 499-6334 in LaGrange County.