To continue our Plant of the Month slot, where we aim to showcase plants available in our garden centres that can really add a splash to your garden, we have chosen Hydrangea for July. Hydrangea are a well-loved garden favourite with many varieties to choose from, whether you are aiming for cottage- or contemporary-chic in your garden. Their name stems from the Greek for ‘water’ and ‘jug’, better translating to ‘water vessel’. They are hardy and deciduous and produce masses of usually either mop-head (large, domed) or lace-cap (smaller, flatter) flowers throughout summer and into autumn. They come in stunning varieties of coloured flowers ranging from whites and creams to pinks, purples and blues. They make an excellent cut flower and look wonderful dried.
How to Grow
As their name suggests, certainly these plants will benefit from a good watering throughout drier weather, and they are best planted in moist soil. Avoid dry, southerly facing area, and avoid areas prone to hard frost or exposed to strong winds as the younger shoots can become damaged. Most Hydrangea are best pruned in spring, leaving the old flower heads in place over winter to protect the new buds. You can then cut back the old flowers to the next buds. Climbing Hydrangea are best pruned directly after flowering.
Hydrangea are well-known for changing colour depending on the acidity of the soil in which they grow. In fact, some varieties are more prone to this than others. White hydrangea tend to stay white for a long time but can age into pink. Furthermore, small differences in soil pH in the microenvironment of the plant can result in one plant flowering with a range of different colours which can look quite striking. Similarly, you might plant the same variety of Hydrangea in different areas of your garden and find that they age to different colour flowers due to local differences in soil pH within your garden. Generally, acidic soils help maintain blue flowers, while alkali soil helps the flowers stay pink. So, if you particularly want your flowers to stay a certain colour, you can use a Hydrangea colourant (helps maintain blue flowers), mulch with ericaceous compost and water with rainwater (to make more acidic) or add garden lime or high phosphorus fertiliser (to make more alkali). Some young plants can produce flowers of different colours in the first few years but settle into one colour thereafter. For many, it’s nice to embrace the shades which emerge naturally over the years, and this also lends itself to a more low-maintenance approach to growing Hydrangea.
Hydrangea favour partial shade, and good companion plants which also favour partial shade include Hosta’s (plantain lillies), daylilies and Astilbe (false goats’ beard). Ferns and foxgloves also add a lovely woodland touch and can look great alongside Hydrangea. With 10% off all Hydrangea in our Cork and Wexford garden centres for the month of July, now is the perfect time to try out some different varieties of Hydrangea yourself.