Sunflowers stretching their necks up to a blue sky, faces turned toward the heavens, are among my favorite sights in the late-summer garden. The cheery yellow flowers make me want to tilt my own head back and soak up the sun. (After carefully applying my sunscreen, of course.)
These oversized blooms are showstoppers – and traffic stoppers – compelling seemingly everyone passing by to pause and look up. If you have the room and a sunny spot in your garden, consider planting seeds in springtime. Flowers bloom late in the game, but the payoff is worth it.
Heat-tolerant annual plants, sunflowers should be planted anew each year. In a location with direct sun (six to eight hours per day), prepare the soil by working in composted manure or other nutrient-rich organic matter. Sunflower seeds can be sown directly into the soil after any danger of frost has passed in the spring. For larger varieties, make sure to allow plenty of room. Seeds should be planted about 1 inch deep, and at least 6 inches apart, depending on the variety you choose.
Plants can be thinned out when they reach 6 inches in height. Sunflowers have long roots that like to stretch out. Mixing a little fertilizer into the soil when you plant will encourage strong, healthy underground growth that can anchor the tall plants throughout the season.
When plants are small, keep well-watered, but once they become established, less frequent watering is best to promote deep roots. Taller varieties may require some staking to support stems as they grow. And just like us, birds, squirrels and even deer enjoy sunflower seeds. Before seeds germinate, you can spread netting over the bed, and once plants grow larger, a wire fence or other barrier should be sufficient to keep wildlife at bay.
When harvesting sunflowers, cut stems in the morning and handle the flowers gently to stave off bruising and wilting. Arrange them in containers that will support their weighty heads and change the water daily for best longevity.
Seeds typically can be harvested around 30 to 45 days after flowers bloom – look for petals to dry up and fall off, and the green base of flower heads to turn brown. Remove heads from stems and take out the seeds. Alternatively, you may want to keep flower heads intact, dry them, and then place outside in fall and water as a welcome treat for birds and other wildlife.
Sarah Marcheschi is a University of Illinois Extension master gardener for Kane County. The “Learning to Grow” column runs weekly during warmer months of the year. Call the extension office at 630-584-6166 for more information. Feedback on this column can be sent to firstname.lastname@example.org.