Zinnias are one of the most common annuals and have been popular since the 1920s. They are easy to start from seed, are undemanding as to soil, and bloom non-stop from spring through frost. They tolerate heat and moderate drought. The only thing they demand is a full sun exposure. Zinnias come in every color of the rainbow except for blue, including bi-colors and even tri-colors.
Zinnias are categorized into three groups: tall, with long stems, best for cut flowers or the back of the flower bed; short, best for mass plantings in beds or borders; and creeping or spreading, which do equally well in flower beds and containers. Tall varieties may reach heights of 36 inches or so. Flowers can be single or double, and may resemble dahlias or cactus. Cut flowers last a long time in the vase, but remove any leaves that will be below the waterline.
My favorite bedding type is the Magellan® series, which I start from seed every year. Magellans are mildew resistant and have the sweet habit of layering new foliage and fresh blooms on top of the spent blooms. Short internodes (stem space between leaves) mean that spent flowers are concealed by fresh blossoms, reducing the need for dead-heading but also means they are difficult to use as cut flowers.
Of the creeping type, the Profusion® series is well named, with a multitude of small blooms on plants that are resistant to Powdery Mildew. Mildew doesn’t affect the flowers, but can make the foliage spotted and ugly. Combat this problem by planting all varieties in locations with good air circulation. Keep the foliage dry when watering – a perfect application for soaker hoses. Avoid boggy soils and over-fertilization, which can result in more leaves and fewer flowers.
Zinnias do not tolerate frost. Seed can be direct sown once weather has warmed in spring. Plants will grow rapidly to flowering size. I prefer to start mine in peat pots so that I can space them exactly in my flower beds. Why peat pots instead of plastic 4-packs? The baby plants dislike root disturbance.
Some seed catalogs sell Zinnias by separate color, while others only offer a mix. I like to select specific colors, reflecting a different color scheme each year. It is hard to select my favorite combination. Red, pink, and white looked spectacular in the Mary Snoddy garden one year, but then salmon, yellow and purple looked fabulous the next. Seeds can be saved from year to year, but hybrids rarely mimic their parents.
Zinnia flowers are beloved by butterflies and bees, so I filled all the empty spaces between perennials in my new pollinator garden with mixed colors of Magellan. The pops of color will last until frost.
Tall Zinnias, grown for cutting, can look a little gawky. Site them at the back of the border to conceal their lower sections.