When to Plant Dwarf Sunflowers Outside
We tend to think of sunflowers (Helianthus annuus and cultivars) as plants taller than a person with huge yellow flowers that produce abundant seeds and not really suited for growing in small yards.
Advances in sunflower hybridizing have resulted in a large variety of ornamental sunflowers that are 3 feet tall or smaller and produce abundant flowers in smaller spaces. Available in many colors, dwarf sunflowers have the same easy-to-grow characteristics as their larger parents and the same basic care requirements.
Dwarf sunflowers have smaller seeds than tall sunflowers grown for seeds, and have smaller seedlings as a result. They are annuals in U.S. Department of Agriculture plant hardiness zones 2 through 11 and must be started each spring anew from seed.
Native to North America, sunflowers don't tolerate frost and grow only when frost-free conditions are present, escaping cold weather by existing as a seed through the winter. Directly sow dwarf sunflower seeds into a garden space with full sun after all danger of frost is past. Plant them 1/2 inch deep and keep the soil moist until they germinate in about a week.
Unlike tall sunflowers which have a strong tap root and need to be sown directly in place for best growth, dwarf sunflowers can be started in pots four weeks before the last frost date and transplanted into the garden. Use a soil-less potting mix and peat pots for the least root disturbance. Choose a sunny window or germinate seeds 3 to 6 inches away from grow lights indoors.
Put one seed per pot, two if you intend to thin to select the strongest seedling. Keep seedlings well-watered but not soggy. When two or three sets of true leaves form and the danger of frost is over, transplant the seedlings still in their peat pots directly into place in the garden, allowing some time to gradually accustom them to outside conditions first.
Some dwarf sunflowers grow well as container plants because of their smaller size. Varieties that grow 12 to 24 inches tall with 3- to 5-inch-wide flowers include "Elf" with bright golden flowers; "Sundance Kid" with semidouble bicolored mahogany and gold flowers; "Big Smile," an early-flowering yellow sunflower with large centers; and "Pacino" with medium yellow flowers.
"Teddy Bear" has shaggy yellow double pom-pom flowers on 2- to 3-foot-tall plants. Use a container large enough to accommodate the stated width for the cultivar and either directly sow seeds, thinning for correct spacing, or transplant already-started seedlings after frosts are over. Place the container in full sun and be attentive to watering since containers dry out quickly, especially when sunflowers are growing quickly.
When sowing seeds directly, allow enough spacing between plants to develop their full width if you want large flowers. If you prefer a hedging or screening effect in borders or mass plantings, space plants closer, realizing that flowers will be smaller and less abundant with thinner stems because of competition. For cut flowers, crowded plantings produce taller plants with taller flower stems.
Make sequential sowings two weeks apart for a continuous supply of cut flowers and non-stop color until fall. Some dwarf sunflower cultivars come in bright mixed colors. "Music Box" grows to 28 inches tall and has solid color or bicolor 4- to 5-inch flowers in cream, yellow and mahogany red. Dwarf cultivars with pollenless flowers that don't shed pollen beneath them as cut flowers are yellow "Munchkin" and "Junior," red double-flowered "Double Dandy" and red and gold bicolored "Firecracker."
You may need: