Hortensia / Hydrangea (Hydrangea macrophylla)

Hortensia / Hydrangea (Hydrangea macrophylla) is one of those plants that can completely transform a shady corner of the garden. Its large, lush green leaves create a beautiful backdrop for enormous rounded clusters of flowers that can appear in shades of pink, blue, purple, lavender and sometimes almost white. A mature Hortensia covered in flowers is spectacular, yet the plant itself has a soft, old-fashioned quality that fits beautifully into a garden.

One of the fascinating things about Hortensia is that the colour of the flowers can change according to the soil. In more acidic soils, many varieties develop blue and purple tones, while less acidic soils tend to encourage pink flowers. This makes Hortensia a wonderful little indicator of what is happening beneath the surface. Soil minerals, pH, organic matter and the living soil environment all influence what the plant is able to take up and ultimately what we see expressed in the flowers.

Hydrangea also has a history as a medicinal plant. The root of certain Hydrangea species has traditionally been used in herbal medicine for the kidneys and urinary system, particularly in connection with stones, gravel and the movement of mineral deposits. The ornamental Hortensia is not generally grown as an everyday edible herb, so I think of this plant primarily as a magnificent garden plant with an interesting medicinal family history.

Hortensia prefers rich, moist, living soil with plenty of compost and organic matter. It loves regular moisture but does not want its roots sitting in stagnant water. Here, it is happiest with morning sun, filtered light or partial shade and some protection from the strongest afternoon sun. Too much intense sun can quickly stress the large soft leaves, while a protected position allows the plant to remain lush and produce those enormous flower heads.

Keep a good layer of mulch around the base to protect the soil, retain moisture and feed the microbial community around the roots. Hortensias also respond beautifully to compost and biologically active soil, and once they find a place they like they can become substantial shrubs. They are easily propagated from stem cuttings, so a favourite old plant can be multiplied and carried into other parts of the garden.

Hortensia is romantic, generous and impossible to ignore when it is flowering. I especially love the relationship between the soil and the changing colour of its flowers. It is a beautiful reminder that what we see above ground is always connected to what is happening in the living soil below.