Sunflowers and the Summer Solstice

Why sunflowers and the summer solstice particularly? There could be lots of reasons, but I particularly like these three: –

The botanical name for the annual sunflower is Helianthus annuus and ‘Helios’ is Greek for ‘sun’.
Heliotropism, is the term for a plant’s tendency to turn towards the sun. It is true that the flower head of the young sunflower tracks the sun as it moves across the sky. Its not the only flower to do so by a long chalk, but it does seem particularly apposite for this Helianthus flower.
The mature sunflower blooms face east, towards the rising sun.

Sunflower Facts

See links below for more information if you’d like to know more about some of these facts.

There are both annual and perennial sunflowers. They are all members of the Asteraceae family which also contains daisies and dandelions.
Helianthus are native to the Americas. This was confirmed when a fossil flower was found by archaeologists in Patagonia in 2010. The beautiful fossil – looking very like a sunflower was identified as being of an early relative of the Asteraceae, dating from 47.5 million years ago.
They have been cultivated for over 5000 years (possibly as long as 8000 years), as a food for humans and livestock, as a dye and for medicinal purposes.
Sunflowers are allelopathic, ie they produce enzymes which dissuade some other plants from growing nearby and can affect the setting of fruit. A study was carried out to find out if the allelopathic qualities of the sunflower could be put to use as an organic weed killer. Results suggested that it could be. Although effective only on certain weeds, it’s use would reduce the amount of synthetic weed killers required.

If you know the film ‘Calendar Girls’ then you may remember the often quoted line: –

“I don’t think there’s anything on this planet that more trumpets life that the sunflower…. A satellite dish for sunshine.”

The film was based on the true story of a group of Yorkshire Women’s Institute members who wanted to fund raise for a new sofa in the hospital family room in memory of the one of their husbands who died of leukaemia. Is it any wonder that the sunflower is used as a symbol of hope by many cancer support groups; Centronuclear and myotubular myopathy; and mental health support. Growing a Sunflower is frequently encouraged to raise awareness and funds.

A Few Tips for Growing Annual Sunflowers

Decide how tall you’d like your sunflowers and check the seed packet. Smaller / dwarf varieties will be fine growing in pots or the ground.
If you want lots of flowers, nip the top bud. This stimulates branching and therefore more flowers.
Sunflowers can be sown indoors in individual small pots or cells. Transplant into larger pots when they’re reasonable sized seedlings. Harden off to plant outside when they’re about 30 cm tall and frosts are finished. NB they do not like having their roots disturbed so handle carefully.
If sowing directly outside protect from slugs. Try using a plastic lemonade / milk bottle with the end cut off as protection for young seedlings.
As their name suggests, a sunflower needs a sunny spot to grow in, at least 6 hours of sun a day.
Taller varieties can act as a temporary wind break or shade giver in the vegetable garden.
If you want to harvest sunflower seeds, tie paper bags over the flower heads to discourage animal pests and catch falling seeds.

Companion planting

Don’t grow them near potatoes or sweet corn (see allelopathic above)
They grow well next to cucumbers and the cucumbers are happy too. The sunflowers can provide shade and some support for the cucumbers to scramble up

Your Garden and the Solstice

In the garden, the summer solstice is one of the four key points of the year in which to take a ‘snapshot’ or record of how the garden is looking. The point being that at the summer solstice the sun is at its highest point, at the winter solstice it is at its lowest. So the amount of direct sunlight entering your garden will be different. With the two equinox, whilst the sun is at a similar height in the sky, the light reaching your garden plants will vary due largely to the presence or absence of foliage on the trees.

Taking a couple of long shots of your garden at dawn, noon and dusk on Midsummer’s Day (Saturday 20 June 2020) will show you which parts of the garden get direct sunlight and when during the day that happens. Depending on the size of your garden, this only takes a few minutes. But repeated at each Solstice and Equinox it gives you a quick reminder of sunlight and shadow in your garden. If the weather is not good enough to show light and shade, you could take photos the day before or the day after; it’ll be near enough to the solstice for this purpose.

Then put the photos together in an easily found folder and make it a key reference for when you’re buying plants.

Even if you take no other photos of your garden as a whole, taking some at Solstice and Equinox serves as a record to show how your garden changes over the years.

Sunflowers at dawn, noon and dusk…

Learning about which flowers will do well in their garden and why is one of the reasons novice gardeners like the personal touch of Plews Gardening Lessons. And taking photos of their garden is something we cover as one of the recording methods in Plews Gardening Courses. It’s a relatively simple way of keeping a check on what plants have thrived and how the garden changes over the seasons. Of course you don’t have to be one of my Gardening Students, just curious to know more about your garden. If you’d like to learn more, why not check out the info on Gardening Lessons?