Hydrangea Fact File
Hydrangea, or Hortensia, grows natively in Asia and America. It is a pretty plant with leaves just as eye-catching as the flower. Its name comes from the Greek words ‘hydro’ (water) and ‘angeion’ (vase) – ‘water vase’ reflects the appearance of the seed.
Hydrangeas bloom from early spring to late autumn, making them an ideal garden plant. Even though there are over 75 species of hydrangeas, most boast only white or just off-white flowers. The beautiful Hydrangea Macrophylla (bigleaf hydrangea) is one of the only species to stray from the norm as its flowers can be blue, red, pink or purple. The exact colour found on this plant often mirrors the pH of the soil; acidic soils produce blue flowers, neutral soils produce very pale cream petals, and alkaline soils result in pink or purple flowers.
The flowers of the well-loved hydrangea appear in two different forms. One is a mophead – these are large round flowerheads resembling pom-poms or, as the name implies, the head of a mop. The other is lacecap, which bear round, flat flowerheads with a centre core of subdued flowers surrounded by outer rings of showier flowers. Most hydrangeas are shrubs growing 1–3m tall, but some are small trees, and others are lianas reaching up to 30m (such as the Hydrangea Anomala). Their leaves can be quite large. Some stay evergreen but the majority are deciduous.
An early settler in America, John Bartram, is credited with the discovery of some of the hydrangea species. He began cultivating what he found on his travels and introduced the flower into gardens in the 1730s. By 1739 the plant had reached England and it quickly spread from continent to continent. However, we have the French to thank for hybridising hydrangeas – they gave us the rainbow of summer colour we enjoy today.
The Hydrangea Arborescens, commonly known as ’smooth hydrangea’, ‘wild hydrangea’ or ’sevenbark’, is well known as an ornamental shrub but in the past was used medicinally by Indians and early settlers to treat kidney and bladder stones. A second species, Hydrangea Cinerea, was also used in the same manner. Hydrangea Cinerea, commonly known as ‘ashy’ or ‘grey hydrangea’, does not bear many flowers but its leaves are large and have a grey appearance (hence the name). This species is very similar to the Hydrangea Radiata (’silverleaf’ or ’snowy hydrangea’), whose leaves are large and silvery-white in appearance – however, this species bears a lot more flowers.
Hydrangeas are moderately toxic to eat. The Hydrangea Paniculata, commonly known as the ‘panicled hydrangea’, is sometimes smoked as an intoxicant despite the danger of illness and/or death due to the cyanide it contains. The Hydrangea Serrata (‘mountain hydrangea’), is known as the ‘tea of heaven’ as it can be made into a herbal tea – the leaves contain a natural sweetener called pyllodulcin. This drink is used to celebrate Buddha’s birthday.