Many people plant them as stabilizers for hedges ~ plant 10 Siberian wild roses then 1 Rose of Sharon. Repeat many times and you get a very straight, well-defined hedge.
The references to the Rose of Sharon have to do with how the plant is used, its resilience during times of famine, or when high winds have knocked down your other hedge plants, and its brightly colored blooms.
Rose of Sharon are Hibiscus.