There’s something about a sunflower that makes people smile.
Maybe it’s because the sunflower is the Jolly Green Giant of the garden, towering (in a benign way) over lesser plants and mere mortals like us. Maybe it’s the active sun-worship that this plant exhibits, turning through the day to aim its radiant floral “face” at the sun. Or maybe it’s the speed with which sunflowers grow – up to a foot a day – that can make an average gardener feel like a horticultural genius.
However you parse it, sunflowers inspire a special affection with their huge, gaudy flowers and stately stalks. Any gardener itching for a challenge can plant a sunflower seed and, with a little attention to the fine points, raise a plant that will catch the attention of everyone in the neighborhood.
It’s true that modern plant breeding has created that contradiction in terms, the “dwarf” sunflower. Varieties like ‘Teddy Bear,’ ‘Music Box,’ ‘Valentine’ and ‘Angel’s Halo’ grow no more than four feet tall. These come in an array of sunny colors, mix well with other plants in the flower border and are terrific for cutting.
“Regular” sunflowers top out at six to ten feet, big enough as plants go. These are the kinds grown commercially (primarily in the Midwest) for bird seed, salted snacks and sunflower oil.
If you’re aiming for a record, though, you have to start with the biggest varieties. What you want are the cultivars bred to rise to heights of 15 or 20 feet – or more. The Guinness World Book of Records puts the height of the tallest sunflower ever grown at 25 feet, 5.4 inches. That skyscraper of a flower was raised in the Netherlands in 1986.
Don’t bother to start your sunflower seeds indoors in pots. Their roots, which penetrate deeply to anchor the plant against wind, grow quickly and resent the trauma of transplanting. Instead, sow them directly into the soil once frosts no longer threaten and nighttime temperatures are consistently over 50 degrees – mid to late May, for most of New Jersey.
Choose a sunny spot with at least eight hours of direct sunlight daily. A well-drained location is a must although sandy soil is not recommended as its loose structure may not offer enough support for roots. While the plants will grow in soil of average fertility, rich soil prods the giants to greater heights.
It pays to dig a big hole, two feet wide and deep, and blend in some extra nutrition in the form of compost, aged manure and a slow-release fertilizer like Osmocote. Seeds should be planted an inch deep in clumps of five to six, with groups spaced about 20 inches apart. Each clump should be thinned to a single plant when seedlings are about a foot tall.
Once the seeds are in and watered, the battle against critters begins. For starters, lay screening over your seeds to prevent birds from making off with them and sprinkle a non-toxic bait like Sluggo around to prevent slug damage. Deer are fond of sunflowers, too, so you may need to grow them behind fencing or near the house.
Conscientious watering and feeding is essential to growing a really big sunflower. One recommended method is to water each plant with about two gallons of liquid fertilizer (mixed according to directions) every single week
If wet, windy weather is on the way, skip the irrigation since it may increase the risk of plants toppling. Generally speaking, sunflowers need not be staked unless they are growing in a very exposed, windy position.
When the petals fall off the flowers and the central disk begins to dry, it’s time to climb a step ladder to cover the seed kernels lest the birds make off with them. Mesh onion bags, loose burlap or paper bags are ideal.
Seed heads can be harvested when the backs turn brown. When heads are completely dry, the seeds can be extracted by hand or released by rubbing against a piece of wire mesh spread over a basket or bucket.
If you’d like to roast the seeds for your own consumption, here’s a recipe from the National Sunflower Association:
Cover unshelled seeds with salted water, using ¼ to ½ cup of salt per two quarts water. Soak overnight. Drain the seeds and pat dry to remove excess moisture. (Skip the soak if you prefer unsalted seeds.)
Preheat the oven to 300 degrees. Spread the seeds evenly on a cookie sheet and bake for 30 to 40 minutes, stirring occasionally. Remove from the oven and cool completely before storing in an airtight container.
Giant sunflowers are annuals, meaning they won’t survive the winter. And that means you have another chance to go for the gusto every season. Onward and upward!