Althea (Rose of Sharon) Double Blooms: Colors & Mystery Double/Single Mix

What colors do double-blooming Altheas come in? I have purple/red singles, plus a white with red center that produces BOTH single and double white flowers. Is this common? Cross-pollination?

Known Double Varieties

• 'Crown of Bohemia' – double golden yellow with orange center (H. rosa-sinensis type).
• Japanese Lantern (H. schizopetalus) – pendulous double red/pink.

Your Mixed-Flower Plant: Rare & Unexplained

Double flowers arise from hybridization, not spontaneous mutation. A 5-year-old plant suddenly producing doubles alongside singles is highly unusual. Cross-pollination doesn't change flower form on the parent.

Verdict

Enjoy the mystery! It's likely a genetic quirk or mislabeled cultivar. No action needed—just a cool garden anomaly.