Zinnia is a genus of plants of the sunflower tribe within the daisy family. They are native to scrub and dry grassland in an area stretching from the Southwestern United States to South America, with a centre of diversity in Mexico. Wikipedia
For early flowers Zinnia seeds can be sown under glass in early spring. Fill a seed tray or pot with compost and cover with a sprinkling of vermiculite or compost. Water moderately and when the seedlings are large enough to handle pot on and harden off before planting outside.
Alternatively, sow seeds thinly a quarter of an inch deep in a sunny bed in the garden. Wait until after all risk of frost has passed. Germination should take place in 7-14 days.
Zinnia are perfect for cut flowers. They should flower from early June until the first frost. I am going to try to sow them directly into the border this year. They like a sunny but sheltered position and once germinated don’t like to be moved. I have seeds of both Green Envy and Polar Bear.
Green Envy – The colour of this summer blooming annual Zinnia is a bright chartreuse green and acts as a wonderful foil to richer shades.
Polar Bear – A bright white double flower that shines out in the border.
Save seeds at the end of the season and in a couple of generations of seeds you will have developed your own strain of zinnia naturally selected to perform well in your conditions. Simply clip off a dried flower head from each flower type that you want to save. Pull the flower apart and remove the seeds inside or simply put the whole blossom full of seeds into an envelope. Seal and identify the flower colour. Keep the seeds in a cool, dry place until it is time to plant next year.