Sunflower, giant sunflower, annual sunflower, perennial sunflower in English, while its French name is tournsol, and in Italian, it is girasole. The French and Italian names, and others, refer to the unusual ability of the plant to turn its flowers and follow the sun as it passes daily across the sky, warming the flowers to encourage pollinators to visit.
The botanical name for sunflower, Helianthus annuus, is very simple, derived from the Greek word for sun, which is helios, and the Greek word for flower, which is anthos. The Latin word annuus means yearly or annual. Interestingly, the annual sunflower occurs naturally in Mexico and adjacent countries and the ancient Greeks did not know this plant. It was given its botanical name during the eighteenth century by the taxonomist Carl von Linne, the Swedish divisor of the binomial plant naming system, who created scientific names for literally thousands of plants and animals during his life.
Sunflower is part of the Asteraceae, the aster family, also known as the daisy family, formerly known as the Compositae, the family of plants that exhibit the daisy form. The flowers of composites are composed of large numbers of small florets with relatively large petal-like outer ones and inner fertile kinds that go on to form seeds.
The annual sunflower is such a cheery plant, with its large, round shape, the colour of sunshine. Children are especially fond of it, as it grows very rapidly. The giant sunflower is an annual and lasts only one summer. Seeds must be sown in spring each year. But the annual sunflower also has perennial relatives that last for many years and flower profusely each summer and autumn.
While a lot of flowers are produced by these perennial cousins, the flowers are smaller in size than the giant sunflower, which can reach more than 30 centimetres across. What they lack in size, they make up in numbers and the plants carry lots of bright yellow flowers, many more than the annual sunflower.
Like the giant sunflower, they make big plants with stems to two metres and more. So, they need to be well placed in the garden, especially if space is limited. Tucked away at the back of a border, their tall stems will wave with golden sunflowers for many weeks in late summer and early autumn. In fact, they have a great autumnal air to them, the yellow daisy flowers setting off the autumn colour of leaves.
Growing perennial sunflowers
One of the very best is “Lemon Queen”, growing to about 1.5 metres tall. This variety has lots of relatively small flowers, carried over the top half of the plant from late summer through into autumn. The colour is a brighter lemon-yellow than most sunflowers, which tend to be deep yellow.
“Capenoch Star” is about 1.5 metres tall too, also with lemon-yellow flowers and the flower centres composed of quill-shaped florets. In the popular variety, “Loddon Gold”, the flowers are fully rounded out as double flowers. “Soleil d’Or” also has fully double flowers of pretty shape.
These named perennial types are relatively well-behaved, spreading out to make a clump but reasonably slowly and they are easily controlled. Even so, they are on the large side for many gardens, but are worth the space for their bright flowers late in the season. Any of the perennial sunflowers can be planted in autumn or spring in any ordinary garden soil. To reduce any wandering tendencies, match them up with shrubs or perennial flowers of similar vigour.
Carrot fly often damages early-sown carrots, its tiny white to yellow larvae feeding on the roots, soon causing the young plants to wither. This is the first generation of carrot flies, which have emerged from over-wintered pupae. Later sowing in May often avoids the first generation, but can be caught by a later generation. The very wet early spring was harsh on the overwintering pupae and seems to have diminished the over-wintering numbers of many kinds of flies, including common house flies and also, the very similar in appearance, carrot fly.
The best remedy is to use a barrier of horticultural fleece or bionet mesh. These products are available in some garden centres, and mail-order online. The fine-mesh products are set up on wire hoops for support. Another very effective way to control carrot fly is with a fence made of plastic or fleece, about 60cm high and tucked into the soil, with no tears or gaps. It can be supported on posts and wire. It is best made narrow to reduce the chances of flies blowing in over the top. A last generation of carrot fly can continue to feed late into winter. If there are some signs of larvae active now, lift and store the remaining carrots, storing only those that have not been affected.
Trees, shrubs and roses
Check trees and shrubs planted since last autumn for water shortage as the roots may not have grown out. Roses have had a good summer, flowering very well but blackspot was widespread after a damp spring. Dead-head spent flowers to encourage late flowers.
Lawns have recovered well in most places, although still showing signs of drought in some cases. Some autumn lawn feed could be applied with rain on the way to give tired lawns a boost. Trim edges where the lawn meets paths and borders for a neat finish.
Spring bulbs are in the shops and this is a good time to plant bulbs of all kinds for spring flowering. They benefit from having a good early start to root growth. Bedding and container annuals will last longer if given some liquid feeding now to keep them going.
Fruit, vegetables and herbs
The recent weather got weeds
going again in the vegetable garden, but was a boost to vegetables that needed water. Soft fruit too benefited considerably, although there were some signs of increased levels of grey mould.
Greenhouse and house plants
Keep picking greenhouse tomatoes as soon as they come ready. Stop feeding most greenhouse plants now and reduce watering gradually as the plants will harden up and stand better through winter. Stop feeding house plants except those that flower in winter.