Ruellia Makoyana Help

A friend gave me some cuttings of her Ruellia Makoyana at the beginning of this year. As you can see they have taken really well. My question is, why haven’t they flowered? I’ve fed it throughout the summer but nothing. What am I doing wrong or does it take a while for flowers to appear. All advice appreciated. TIA x

 

I can only speak for Ruellia brittoniana, but that took two years to flower from seed, despite developing into a big, healthy plant in year one.