Blue bushes are often referred to as such because of the colour of the flowers festooned along their branches. While not the most common, there are several bushes throughout the Americas, Europe and Asia that produce blossoms of varying shades of blue. Some of these have practical herbal uses, while others are potent for attracting birds and insects.
Known scientifically as Perovskia atriplicifolia, Russian sage is a perennial indigenous to central Asia, which includes not only Russia but Afghanistan and other neighbouring countries. This shrub, which can grow to between 90 cm and 1.5 m (2 and 5 feet) tall, is not part of the same species as the sage plant, but does have a similar fragrance. And unlike the usual sage, this bush produces a hedge full of light blue flowers, sometimes bordering on lavender. Aside from their aesthetic attributes, these flowers have been smoked or ingested by locals as an herbal remedy.
Nikko blue hydrangea
Hydrangea is a shrub common around the world from Asia to the Americas. These plants often grow as high as 3 m (10 feet) and are recognisable from the bouquet-like cluster of four-petal flowers on each bush. While some hydrangea bloom in pink or white, the nikko blue variety produces flowers of a deep azure. The sole factor in determining the colour of a hydrangea's flowers is the acidity of the soil; a high acid content will cause the shrub's flowers to turn blue. These bushes grow mostly from late spring until early autumn.
The wedgewood blue, known by botanists as syringa vulgaris, is a variety of the well-known lilac bush. Although the word lilac, when referering to colour, means a light shade of purple, the blossoms on a wedgewood blue are mostly sky blue with a light border of lilac around the edges. The rounded bush can grow up to 1.8 m (6 feet) tall and 2.4 m (8 feet) wide, with thin, spade-shaped green leaves hanging from the branches. It is typically in May that the flowers bloom and are at their most colourful.
The nanho blue is a variety of the buddleja bush, more commonly known as the butterfly bush. There are more than 100 different varieties of this shrub, which can be found in Asia, the Americas and Europe. One commonality they share is that they are all typically rich in nectar and tend to attract butterflies and other insects and even the occasional hummingbird. The nanho blue, which can grow to about 3 m (10 feet), produces clusters of small flowers of a deep indigo blue that hang in clusters from the end of each stem.