Below is a photo of the single Sunflower ‘Sun King’ planted in our community garden patch this year.
It has been entirely worth it!
So many creatures have enjoyed this flower, including humans.
It is no longer in flower and many birds are now picking out the seed or picking fallen seed off the mulch.
In the same small bed we have successfully grown arugula (we call rocket / roquette), carrot, Chinese gooseberry, parsley and bok choy and have recently planted out three cabbage seedlings. The sunflower seems to have had no negative impact on the productivity of our patch. Of course I qualify that statement with the following - the soil in the bed was improved with a lot of compost prior to planting out, we have watered regularly, mulched heavily and treated with vermicaste (worm castings) tea every two to three weeks.
Worth noting... we intended to grow more than one but only this one plant survived the germination and early growth period. So if you want one you may be better planting three or four.
Our experience has been well worth it and we will be planting sunflowers every year.
Also worth noting, elsewhere in the common / public area of our community garden, we have planted out dwarf sunflower varieties to great effect and enjoyment by many. They produce six or more flowers on each plant. So don’t overlook this as an option too. (Varieties were: ‘Teddy Bear’ and ‘Dwarf Sunsation’.)
So my advice - go for it!