Zinnias are warm-season annual flowers that typically bloom from early summer through fall. They are popular among gardeners for a multitude of reasons, including their vibrant beauty and easy care along with their ecological benefits, such as supporting biodiversity and improving soil health.

Having discussed the various stages of the life cycle of the zinnia plant leading up to the maturity stage, it’s time to discuss the much-awaited flowering stage and what growers need to do during this phase. To the utter relief of growers, zinnia buds ideally begin to appear at around four to six weeks of the seeds’ germination, while flowering begins after six to eight weeks of germination. This duration is highly dependent on the different zinnia varieties and the prevalent growing conditions as well.

At the stage where buds begin to appear, it is important to ensure that the soil around the plant turns dry before the next watering cycle. It is also important not to water the plant frequently. However, each time it is done, the plant should be watered deeply.

When it comes to the fertiliser requirement of the plant, it is important to note that the nitrogen component being provided to the plant till this stage has outlived its primary usefulness — to ensure better foliage growth. With the flowering stage fast approaching, it is now important to switch to a fertiliser that is rich in potassium and phosphorus. These fertilisers are commercially available at gardening stores and plant nurseries.

From cactus-like spikes to dahlia-style doubles and simply daisy-like arrangements, zinnias offer a floral fashion show…

The colourful zinnia flowers attract pollinators to the garden but, simultaneously, they may also attract pests and diseases to the plant. Powdery mildew, for instance, is a fungal infection that manifests as white powder on leaves. It is a common issue faced by zinnia plants due to hot and humid conditions. Spider mites, aphids and other pests may also attack the zinnia plant.

To ward off pest attacks, the plant should be sprayed with a mixture of one spoonful of neem oil in one litre of water. The plant should be sprayed and soaked with this mixture, with special emphasis on the underside of the leaves.

Unlike a few other seasonal flowers, the zinnia has a number of petals with varying patterns. A zinnia may have a single or double row of multiple petals. The double row gives the flower a fuller look, while the single row of petals makes the flower lighter and cuter.

The arrangement, shape and size of the petal may also contribute to the classification of different zinnia flowers. Flowers with pointed petals are referred to as cactus-like zinnia, while those with multiple layers of petals are referred to as dahlia-like. Zinnias with the basic single-layered arrangement are known as daisy-like zinnias.

Zinnia flowers from the taller varieties are used as cut flowers in different floral arrangements and bouquets. Many growers opt to cut the flowers a couple of days or more before they achieve full bloom on the plant. In floral settings, including in a vase with water, these half-bloomed zinnia flowers continue to blossom and stay fresh for the next five to seven days.

When the flower achieves full bloom on the plant, it should be removed within the next few days. Deadheading, or removal, of such zinnia flowers is important because it is believed that the flowers sap plant energy as they dry up and, thus, slow down the growth of blooming zinnias.

Regardless of its type and kind, the array of colourful zinnia flowers with a green background makes for a delightful view for the onlookers, making it a highly recommended seasonal flower. It beautifies the surrounding area and is easy to grow, especially for those who are new to gardening. The zinnia ensures refreshingly attractive and colourful flowerbeds at home, flower spaces in gardens, side-walks, pots, pavements and parks.

Please send your queries and emails to doctree101@hotmail.com. The writer is a physician and a host for the YouTube channel ‘DocTree Gardening’ promoting organic kitchen gardening

Published in Dawn, EOS, August 10th, 2025