Allium Hollandicum 'Purple Sensation' Side view of one globe shaped head in full flower with others behind, Against blue sky.

Saguaro cactus, Carnegiea gigantea, Dramatic view from below of a single stem with arms branching upwards towards a blue sky with wispy clouds, its shadow on a white wall.

Plum, Prunus domestica 'Blue tit', Cluster of white blossom with small leaves on a single twig.

Plum, Prunus domestica 'Blue tit', Cluster of white blossom with small leaves on a single twig.

Plum, Prunus domestica 'Blue tit', Cluster of white blossom with small leaves on a dark twig with others around, Against blue sky.

Candelabra tree, Euphorbia candelabrum, Side view of several ridged spikey columns in sunlight against a blue sky.

Aloe vera, Two plants in foreground, one with a flowering spike and others behind, Growing on a dry terrain against a blue sky.

Rose mallow 'Blue Bird', Hibiscus syriacus 'Oiseau Bleu', A single purple blue flower with white stamens.

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

Summer hyacinth, Galtonia candicans, Pendulous white flowers with black tipped stamens.

Agapanthus africanus, Close view of a white flowers emerging from an umbel shaped flowerhead.

Agapanthus africanus, Close view of blue purple flowers emerging, from an umbel shaped flowerhead, against a green background.