Plant fast growing flowers as fillers between early and late blooming plants to buffer empty space in the garden. Use them to provide interest in new garden beds while perennials become established.
To find fast growing flowers, read the labels when you shop for plants and seeds. Look for information about the average number of days from planting to bloom, as well as the length of the blooming period.
Spider Flower (Cleome hassleriana)
Spider flowers begin blooming in June and continue until frost. These annuals self-seed aggressively. Flowers come in various shades of pink, purple, white and bi-color. The plants reach heights of 3 to 6 feet. They thrive in full sun or partial shade, and tolerate mild dry conditions once established. Regular watering enhances the number and quality of the flowers.
Cosmos (Cosmos bipinnatus)
Also called Mexican aster, cosmos plants grow up to 7 feet tall. From June until frost the plants are covered with flowers in white, magenta or shades of pink. The yellow centered, daisy-like flowers attract butterflies with their rich nectar. Cosmos tolerate poor soil and dry conditions. They self-seed readily.
French Marigold (Tagetes patula)
If you plant French marigold seeds outdoors on the last frost date for your area, you can expect to see flowers on the plants in six weeks. The plants will continue to bloom until frost. Keep the spent flowers pinched off to make the plants bushier. Flowering may slow down in summer heat, but the plants will begin blooming again when cooler fall temperatures arrive. French marigolds grow 12 to 15 inches tall, in single and combination colors of yellow, gold, red and orange. They make excellent borders and container plants. French marigolds prefer full sun and evenly moist soil.
Zinnia (Zinnia elegans)
Zinnias grow quickly from seed. The plants begin blooming four to six weeks after planting, depending on the type of zinnia. Over 100 zinnia varieties present gardeners a wide selection of color, size and petal type. Dwarf zinnias may reach only 6 inches in height, while large flowered varieties reach 3 feet or more. Zinnias are drought tolerant, sturdy plants that bloom all summer until frost. Plant zinnias in sunny beds and borders; smaller varieties are ideal in containers. In humid areas, plant zinnias where they have good air circulation to minimize problems with mildew.