Zinnia elegans Seeds | Pink Zinnia
LATIN NAME: Zinnia elegans
COMMON NAME: Pink Zinnia
Plant Profile
Pink zinnia is the soft-coloured form of the dahlia-flowered class, with blooms in shades from pale blush to deep rose, 8-10 cm across, on plants 60-90 cm tall. The colour range within a single packet is wide, which is either the charm or the frustration of growing it from seed.
The plant is upright and branching, with the rough leaves of the genus, and it flowers from July until frost. Pink zinnias are among the best plants for a late-summer border because the colour sits easily with almost everything and the flowers last in heat.
Zinnia elegans comes from Mexico and Central America, and the garden forms have been selected for more than two centuries. The pink strains are not a distinct botanical group: they are selections within the species, and they will segregate in the next generation.
Science & Biotechnology
Pink in zinnia is a dilution of the anthocyanin pathway: less pigment, or a different balance of cyanidin and pelargonidin, gives a paler flower. That is why pink strains produce a spread of tones when grown from seed, and why named clones have to be propagated vegetatively.
Zinnias are one of the few garden annuals native to the Americas that have become important cut flowers worldwide, and they are also a model for the genetics of flower doubling. The transition from a single daisy to a double bloom involves a change in floral organ identity, not simply more petals.
The species is susceptible to powdery mildew and to Alternaria blight, both of which are worse in humid climates. Good airflow, drip irrigation and rotation are more effective than sprays in a garden setting.
Uses & Benefits
Pink zinnias are the easiest colour to use in a mixed border, and they are equally at home in a vase. They are a standard component of summer bouquets, and they last a week in water if the stems are cut early and conditioned.
In the garden they are a butterfly plant, and they are one of the few annuals that will keep flowering through a hot dry August without extra water. Commercially the pink strains are grown for floristry and for farmers markets, and they are a mainstay of the seed trade for cut-flower growers.
Growing from Seed
Sow at 21-24°C, 5 mm deep, six to eight weeks before planting out, and germinate in five to seven days. Keep the seedlings on the dry side and in strong light to prevent stretching.
Plant out at 30 cm apart in full sun after frost, and pinch at the fourth leaf for a bushier plant. Water at the base, space for airflow, and feed lightly; too much nitrogen gives leaf at the expense of flower. Harvest when fully open, and deadhead the spent blooms to keep the plant producing into October. In a short season, sow under cover in April and plant out in early June; the plants catch up fast once the soil is warm.
Our Take
The most useful colour in the zinnia range for a mixed border, and the one to sow if you only have room for a single row.
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