Annual flowers are popular garden plants because they usually provide color in the garden for the whole growing season. The trick to keeping the flowers blooming with vibrant color is to plant them in the right climate and soil conditions. While some plants like the cool moist shade garden, others thrive in dry, hot conditions of the full sun.
Marigolds are members of the daisy family and a popular annual for the garden because they are easy to grow. Marigolds can have single or double flower heads and are available in shades of white, yellow orange and maroon. Some find the aromatic marigold offensive. French marigolds (Tagetes patula) are small plants with small flowers, while African or American marigolds (T. erecta) are taller with large blooms. Marigolds do best in a hot, sunny part of the garden, but will not be harmed if they are shaded in the early morning or late afternoon.
Zinnias (Zinnia elegans) are a member of the daisy family. The showy flowers bloom in every color except blue and are available as single or double blooms. Dwarf zinnia make good border plants for a sun garden, while tall zinnia are attractive at the back edge and make beautiful cut flowers. The zinnia blooms from early summer until the first frost. The blooms range from an inch and a half across to large blooms of up to 6 inches. For best results, plant zinnias in full sun once overnight temperatures stay above 50 degrees Fahrenheit. Zinnia does especially well in climates with hot, dry and long summers.
Petunias (Petunia x hybrida) are a member of the nightshade family. Their trumpet-shaped blossoms can grow up to 5 inches in diameter. The flowers can have fringed, frilled or ruffled edges, and some are double-flowered and look like carnations. Petunias grow best in an area that gets fun sunlight for at least half of the day. If they don't get enough sun, they may not flower.
Verbena grows well in the full sun, but in hot climates of the desert and the Deep South, they need a light shade to protect them from the heat. While technically a perennial, it is considered a tender plant and grown as an annual. Most verbena (Verbena X hybrida) are trailing, low growing plants. They make good plants in rock gardens and as a ground cover. They also provide a trailing accent for containers and hanging baskets.
Strawflowers bloom in colors of red, yellow, orange, salmon, pink, purple and white. Strawflowers blossom from early summer until frost. The heads of the strawflower (Helichrysum bracteatus) are perfect for drying to make bouquets for the winter. Strawflowers thrive in the full sun of long, dry, hot summers.