Zinnia (Zinnia) Dahlia-like blossoms 4 to 7 inches across on plants 2 to 3 feet tall; rounded, pointed or cactus-type petals. Round blossoms 1 to 2 inches across on plants 6 to 12 inches tall. Mixed colors and bicolors. Soil and Light Full sun. Tolerant of all soil types. Planting Start seeds 6 to 8 weeks early indoors, or outside after frost danger. Comments Use dwarf varieties in borders, rock gardens, or window boxes. Try tall varieties in mixed beds or planted alone.