Growing sunflowers is a rite of passage for many young children in the UK, competing with siblings to see whose flower can grow the tallest. My girls are too young to appreciate it this year, but I thought I'd do a test run anyway. Especially when I heard that you can get black sunflowers.
Black Magic F1 sunflowers have dark maroon red petals instead of the regular golden yellow colour, and can appear nearly black depending on the light. I have seen pictures of larger, blacker sunflowers on the internet, but I couldn't find seeds to grow them myself. By contrast, Sunflower Black Magic F1 seeds are easy to obtain, and are stocked by several suppliers. I purchased Johnsons' (I'll probably try Mr Fothergill's next year). They are not expensive at around £2.50 for 20 seeds and they are very easy to grow.
I started them right at the end of May in small pots, then planted them into the their final position, against a sunny wall, once they were established. The UK had an unusually long and hot heatwave this summer. I missed a couple of daily waterings and kept the seedlings in pots too long; their roots were escaping from the bottom. This neglect meant fewer survived and thrived than should have, but in the end I had six healthy plants.
The first flowers opened in mid August, and as a multi-branching variety, the plants could continue to bloom until the first frost. That's unlikely to happen for me due to the destructive whirlwind that is my two-year-old daughter. She's already beheaded one; luckily I'd taken a photo of it first.
Most of the plants got close to 4 feet or 120cm in height, reaching their expected maximum. This type of sunflower isn't going to win a 'tallest sunflower' competition against the giant yellow kind. Also, there was some variation in the stem and flower colours, as shown below. I'm unsure if this was due to natural variation in the seeds - which all came from a single packet - or if it was a packing error. I got dark-stemmed, red wine coloured flowers, and a couple of green-stemmed flowers whose petals were red with yellow tips. All flowers were around 5 inches (12.5cm) in diameter.
I've read that F1 sunflower varieties - including Black Magic - will not breed true from harvested seeds, so I'll have to buy fresh ones to plant next year. I plan to do so; I think these are stunning flowers for a very small amount of effort. I'll also sow them earlier to stretch out the potential flowering period. If I find seeds for other dark varieties I'll try those too to see how they compare.