Rose mallow, Hibiscus syriacus 'Blue Bird', purple blue flower and bud growing on a shrub against a green background.

Rose mallow, Hibiscus syriacus 'Blue Bird', single purple blue flower growing on a shrub.

Rose mallow, Hibiscus syriacus 'Blue Bird', purple blue flower and buds growing on a shrub against a green background.

Rose mallow, Hibiscus syriacus 'Blue Bird', single purple blue flower growing on a shrub against a green background.

Rose mallow, Hibiscus syriacus 'Blue Bird', purple blue bud opening among green leaves on a shrub.

Rose mallow, Hibiscus syriacus 'Blue Bird', purple blue buds opening among green leaves on a shrub.

Oak, Quercus robur, Acorns growing on the branches of tree in late summer.

Foxglove tree, Paulownia tomentosa, purple flowers on a panicle on a tree in the spring.

Foxglove tree, Paulownia tomentosa, purple flowers on a panicle on a tree in the spring.

Foxglove tree, Paulownia tomentosa, purple flowers on a panicle on a tree in the spring.

Water droplets on leaves of Smoke Bush, Cotinus Grace plant.

Water droplets on leaves of Smoke Bush, Cotinus Grace plant.