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Growing Sunflowers for your Cutting Garden

Robin Trott, UMN Extension Educator

Cherry Rose. Robin Trott.

The Sunflower, or Helianthus, is a very popular flower to include in an annual cutting garden. A native of North America, the sunflower comes in a variety of sizes, growing habits and colors, making it an ideal choice for the home gardener. From the Giant sunflowers like "Kong", to the multi branching "Italian White" to the petite "Teddy Bear", an 18" tall puff-ball; there is a sunflower to match every gardener's taste and purpose. One of my favorites from last year was a pollen-less variety called "Cherry Rose". This 6' tall, branching plant is covered with 5" lemon yellow blossoms with red overtones. Grown in full sun, the lemon color abounds, in a more shaded site; the dark plum color is dominant. Another excellent choice, "Ring of Fire", is a mid-height plant (4-5') with 5" blooms. This late bloomer boasts bi-colored petals with a dark red base and golden yellow tips surrounding a chocolate brown center. For the giant sunflower enthusiast, "Kong" is as big as it gets. Reaching 12 feet tall, "Kong" is even more impressive because it's multi-branched and covered with 4-6 inch yellow blooms offset by large, dark green leaves. The most versatile sunflower in my garden last year was the "Music Box". "Music Box" grows into a stocky, 2 ½' bush of abundant, multi-branching 4-5" golden, daisy like sunflowers. These petite, buttery flowers were ideal in mixed fall bouquets, and bloomed prolifically until frost.

Ring of Fire. Robin Trott.

Keep in mind these cultural practices once you have selected your perfect sunflower variety.
  • Select a site that receives at least 6 hours of sun a day. (More is preferable)

  • Sunflowers prefer loose, well-drained, rich soil; so amend with compost if you have heavy clay or sandy soil.

  • Sow seeds directly into the garden once the soil has reached 50°. (Cooler than this will slow development.)

Music Box. Robin Trott.

  • Plants seeds at a depth 2 times their width, and space close (6") to promote tall plants; and small, bouquet sized heads. This close spacing will soon shade out weed competition and mature plants will protect and support each other.

  • Sunflowers are heavy feeders, and should be fertilized. Side dress with a balanced fertilizer (10-10-10) every 21 days during the growing season.

  • Keep your sunflowers weed free. Weed competition reduces the quality of your sunflowers.

Kong. Robin Trott.

  • Tall sunflower varieties will need support to protect them from wind damage. Stake them or grow them through horizontal support netting to ensure your plants remain standing after our typical summer "hazardous" weather.
Harvest your sunflowers during the coolest part of the day. The plants should be free of dew and moisture. Cut when petals begin to lift off the face, but are not completely open. Make sure your cutting tools and containers have been sterilized with a 5% bleach solution. Cut stems at least 24" long and at an angle for best results. Sunflowers prefer clean water to floral preservative. (Floral preservative can actually over-hydrate your flowers, making them wilt.) Place your cut sunflowers in a cool place as soon as possible after cutting. If wilting occurs, don't worry, leave them in water for 24 hours, and they should perk right up. Vase life for fresh cut sunflowers is 7 to 10 days, with pollen-less flowers having the longest vase lives.

Sunflowers are a colorful choice for your garden, make long lasting cut flowers, and provide food and habitat for wildlife. It's not too late to start them for this gardening season. Select your cheerful sunflower variety today, and get growing!

Until Next Time, Happy Gardening!
Bring me then the plant that points to those bright Lucidites swirling up from the earth, And life itself exhaling that central breath! Bring me the sunflower crazed with the love of light.
~ Eugenio Montale
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