Sunflowers are surely the most photogenic of all flowers and they are the very essence of summer. When you see their large, daisy-like flowers on tall stems, you can’t help but think of hot, sunny summer days. but not all sunflowers are the same. If you want giant sunflowers that tower above you then you need to buy seeds of ‘giants’ because most grow to about 1.5m high. There are also dwarf kinds that only grow to 60cm. So get the right seeds before you start.
How you grow them will also make a huge difference in your results. Even giant types will only grow to 1.5m or even less before they flower if they do not have lots of nutrients in the soil. A sunny spot and lots of water and fertiliser are essential to getting big plants.
Just as important is that the plants are grown quickly and without any checks to growth. Sunflowers cannot be planted outside till mid May because frost will kill them. If they are sown too early and kept in small pots on the windowsill for too long they will become starved and ‘lanky’ and will never recover their vigour when planted outside. That is why the next few weeks is the ideal time to sow your seeds. The seeds are large and easy to handle so you can easily sow one per pot or cell. Sow the seeds on their edge, about 1cm below the soil surface. The seeds germinate quickly on the windowsill and seedlings will appear in about a week to 10 days. Keep them in good light and they are then perfect to plant out when they are still small and have one pair of fully grown leaves, in addition to the two seed leaves.
When buying your seeds also look to see if they are going to grow one main flower or whether they will branch and form several flowers at the top of the stems. When sunflowers are grown commercially as cut flowers they are grown close together so they only produce one flower per stem and then the whole plant is cut. But if you want a plant with lots of flowers or if you want tall plants you will need to give them room to grow! For giant plants that reach more than 2m high you need to give the plants lots of room – possibly 1m apart. For most others you need to plant them 60cm apart – these are large, leafy plants.
And you do need to dig in lots of home-made compost or well-rotted manure, especially if you are growing giants. You do not want them to start to bloom until the plants are well grown and attained height.
And while we all love golden sunflowers, there are many other colours to choose from. You can now get seeds of sunflowers in every shade of yellow and also reds and pinks and almost black. I did grow ‘black’ sunflowers a few years ago and while I like the various different kinds, I longed for bright, golden sunflowers instead, though the bees seemed just as happy with the dark flowers.
The creamy white varieties are especially lovely in the garden and most branch freely and make good cut flowers. And the ‘double’ kinds are really pretty and they seem to be particularly admired by butterflies in my garden.
Whatever kind you want to grow, the next week or so is the perfect time to sow.
One other word of warning: Slugs and snails love the taste of young sunflower seedlings. So grow a few more than you need and make sure you use your favoured way to protect your plants immediately you plant them out or they will disappear overnight!