With their richness and intensity of colours, zinnias give the brightest colour mixture of all the sun-loving annuals to brighten up our gardens during the coming summer through to late autumn.
A member of the daisy family, zinnias comprise some twenty species mostly native to Mexico and tropical America and were first introduced into European gardens in the 18th century.
Zinnias are named to honour Johann Gottfried Zinn, a noted German physician and professor of botany.
Hybridisers have vastly improved the many varieties, types and forms of the original daisy-like zinnia into the stunning array we have today.
Modern varieties come in a wide range of heights and forms. Flowers can be plain, ruffled, bi-coloured or striped in colours of white, cream yellow, orange, scarlet, crimson, purple and green in single and double forms with a size range in large, medium and dwarf.
The most popular strain is probably the tall dahlia-flowering types of Zinnia elegans hybrids with their large, double blooms on long, strong stems which grow to about 25-75cm high in a mixture of colours.
I like Zinnia elegans ‘Envy’ with its unusual double, chartreuse green, flowers that are very popular with flower arrangers. The Zinnia elegans Ruffle Series has spectacular double flowers in most colours.
Zinnia Thumbelina is a dwarf, dome shaped plant growing to about 15-20cm high with heavily studded miniature blooms with double and semi-double flowers in mixed colours. The ideal plant for rockeries.
Seedlings can be planted now, 30cm apart for tall varieties and 15cm for the dwarf types, into soil that has been pre-prepared with aged compost. Zinnias love lime, so if your soil is acidic an application a few weeks prior to planting is beneficial.
When the plants are about 45-50cm high, a mulch of well decayed compost will help keep the roots cool and conserve the soil moisture. At the start of the bud up stage, give a fortnightly application of a liquid fertiliser to help improve the size and quality of the flowers.
At the full bud stage many gardeners disbud them to encourage branching and increase the quantity of blooms. Disbudding is the removal of any buds that are crowding other buds. There are hardly any flowers which wouldn’t produce more blooms if relieved of their excess buds.
Keep the flowers cut to prevent seeding and they should continue to put on a dazzling display until late autumn.
Aphids on march
At this time of year aphids create havoc in the garden by massing on new growth, resulting in sooty mould on the growing tips and leaves.
Aphids rob plants of sap causing poor growth, wilting and misshapen flowers.
There are many different types of aphids that come in a range of colours but they all feed in the same way – that is, they use a proboscis (like a hypodermic needle) to pierce into plant material and suck out the sugary juices.
If you don’t want to use chemical sprays you can hose them off or encourage friendly insects like the ladybirds and hoverflies that attack aphids to the garden. There is also an old remedy made up by mixing four teaspoons of lemon juice and two cups of water then sprayed on affected plants. A substance found in lemon juice kills the aphids.
Daily: The Emu Valley Rhododendron Garden, at Romaine, Burnie. The rhododendrons are putting on a dazzling display at the moment. Open from 9am-5pm. Tea room open from 10am-4pm.