March 2012: Sow Some Summer Sunshine...Sunflowers
Archeologists have found sunflower seeds at Native North American sites dating back 3,000 years. The Incas of Peru carved stone pictures of the sunflower (the sun god come to life) on their temples. Today, we enjoy a tremendous range of beautiful garden sunflowers. Recently, European and Japanese hybridizers have played with our native flower and are developing exciting new varieties. You can find yellows, golds, reds, mahoganies, bicolors, singles, semi-doubles, doubles, dwarfs, mediums, and very talls. Use tall ones for backgrounds and along fences, midsize for borders and cutting, and dwarfs for bedding and containers. Sunflowers form an interesting hedge, or a screen for your compost pile. They are one of the best plants for attracting bees to your garden. The world’s tallest sunflower was grown in Germany and topped out at 26 feet, 4 inches. The largest sunflower head was grown in British Columbia and measured 32 ¼ inches across (Come on, Ramsey County Gardeners!!!). In the next few years, look for breeders to develop more pollen-free (sterile) varieties and more varieties with pastel colors.
The familiar sunflower is Helianthus annus (helios = sun, anthos = flower, annus = year) It has a single, large flower on top of a tall stalk. To be precise, each head or flower is actually composed of 1,000 to 2,000 tiny individual flowers coming together in two mathematically exact spirals (the Fibonacci sequence). Ray flowers, around the edge, produce the petals and do not form seeds.
You can find a variety of sunflowers to fit any size garden. The larger sized varieties grow 12 feet or more, and are ideal for bird, squirrel, chipmunk, mouse, and bear food...as well as us humans. Seed heads may be covered with cheesecloth or a close woven plastic mesh bag to keep out the goldfinches and squirrels. Harvest the seed heads when the head turns yellowish brown; bring indoors to dry.
Kids love the large size of the common sunflower. The big seeds are easy for kids (and grownups) to handle and grow. One fun thing to do is to plant sunflowers to form a play room for kids. Plant some pumpkins too. Try growing some of the giant varieties like ‘Large’ or ‘Mammoth Gray Stripe’, ‘American Giant’, and ‘Kong Hybrid’. ‘Teddy Bear’ and ‘Honey Bear’ are medium sized plants with golden yellow, fully double flower heads. ‘Sunspot’ is a cute 2 foot sunflower with 10 inch heads.
Sunflowers are easy to sow and grow. Choose a well drained soil in a sunny spot that receives 6 or more hours of full sun daily. Sunflowers thrive in a wide variety of soils and pH. The young sunflower heads turn to follow the path of the sun as it travels across the sky (heliotropism), but tend to face east after the flower heads open. Locate them so as to enjoy their blooms. Amend the soil with organic matter. Sunflowers do not need additional fertilization, unless the soil is extremely poor. In fact, over- fertilization may result in lush plants with weak stems and decreased flowering. Plant the seeds in groups, wide rows, or big beds, about an inch deep after the soil has warmed (day/night temperatures over 50 degrees F). You may have to protect the seeds and young seedlings from the birds and other wildlife by using netting or a row cover. Young plants often provide a snack for deer and should be protected by wire cages or fencing in deer country. Seedlings may be started indoors in 4 inch peat pots. Transplant outdoors after it is warm and after the first true leaves have formed. Thin the tall varieties to 2-4 feet apart, and other sizes somewhat closer (check the package instructions). Taller varieties may need support, especially if the seed heads grow large. Mulch to conserve water and control weeds.
Grow some sunflowers for cutting. There are now varieties that do not produce pollen and will not stain your furniture or tablecloth. Choose types that grow 3 or 4 feet tall and have smaller flowers. Many of the smaller types have multiple, flowering branches, and bloom longer than singles, and to some people appear tidier than the big, tall, gangly types. Space the plants 9-12” apart. You want an abundance of smaller sized flowers that are easy to handle and are of a nice size for bouquets. Plant seeds every 2 weeks for a steady supply of blossoms. Sunflowers can stand a little drought after they are established. However, for the cutting garden it is best to keep the soil evenly moist, but don’t over water – sunflowers hate wet feet. Depending on the variety, you should get flowers in 9-14 weeks. Cut the sunflower stems (when the flowers are almost completely open) with a sharp knife or shears in the cool morning or evening. Wait until the dew has evaporated. Strip off lower leaves and damaged leaves. Place immediately into water with commercial floral preservative. Every 2-3 days cut off ½” of stem under water; replace the water with fresh water, and add new preservative. The flowers should stay fresh for 7-10 days.
Previous Garden Sage Columns
Planting Under Trees
50 Latin Names of Plants
It's Time to Plant Bulbs
The Beautiful Crabapple
Beat the Japanese Beetle
Bringing Birds to Your Backyard
The Rotten World of Composting
The Joys of Basil
Switch to Seeds for Pricy Foliage Plants
Repot orchids for re-bloom
Protecting Plants Against Winter Injury
Is Your Tree a Hazard Tree?
Eat Your Landscape
Belles of the Border
Superstar Seeds to Try
New Years' Resolutions for Gardeners
Just When You Thought You Were All Done
Digging & Storing Dahlia Tubers for Winter
Gardening for Wildlife
Frond of Ferns
All American Selections
The fine art of borrowing ideas
Be Seed Smart
Some Like Them Hot
Dec 2008/Jan 2009
Feeding the Birds
Winter Damage to Evergreens
Putting Your Flower Bed to Bed
The Return of the Tulips
Oh Dear, Oh Deer
DANGER IN THE GARDEN (ESPECIALLY FOR CHILDREN)
Growing Peaches in Minnesota
Insects That Might Bug Us This Summer
Avoiding Crying After Buying... Wise Mail Order Shopping
On Comet! On Cupid! on Donder and Blitzen! On Garden Catalogs
Latin is for Lovers ... of Plants
Use Those Leaves!
The Coneflower Explosion