These clans were created by four cats, each of them were outcasts from other clans. These cats despised their former clans, Thunderclan, Riverclan, Windclan, and Shadowclan. So, they made new ones.
The four cats, Robinfleck, Beewish, Springwatcher, and Aspenwing, renamed themselves after flowers they have seen on the way to the new territory. Robinfleck became Oleanderstar, Beewish became Lavenderstar, Springwatcher became Azaleastar, and Aspenwing became Bluebellstar. The cats claimed their territories, Bluebellstar was the last, and he was furious. The tom screamed at the others, saying that they'll have to share their territories with him, since there were no other places fit for a clan. The others refused, telling him that he should find somewhere else to put his clan. "Very well," Bluebellstar hissed, his eyes narrowed. "But if you ever need Bluebellclan's help, don't even think of asking." The tom then stalked off, finding his territory well away from the others.
Oleanderstar had chosen the thick forest, knowing that with his thick fur, he could never be cold there. Lavenderstar chose the nearby grassland, she knew that it'll be easier for her to hunt there than in the forest. Azaleastar chose the only territory with a waterfall, knowing that with her swimming skills, she could easily catch fish whenever. Bluebellstar chose the territory on top of Azaleastar's. This way, he thought, he could watch the other clans suffer while his clan thrives.
The clans began to grow. Oleanderstar invited in rogues that were strong and buff. Lavenderstar invited loners that were calm and intelligent. While Azaleastar invited everyone that even glanced at her territory. Some cats from Bluebellstar's former clan had followed him and joined his clan. As the clans grew, food became more and more scarce. So, the clans expanded their territories, and it has been this way ever since.