Hydrangeas are so easy to grow, anyone can grow them and they will tolerate almost any type of soil. They need very little looking after and are very hardy.

Hydrangeas are really popular shrubs with big flower heads in shades of pink, white or blue. The mophead and lace-cap hydrangeas are known for their ability to change colour in different types of soil.

Mophead flowers are large round flower heads that look like pompoms or as the name suggests, like the head of a mop. In contrast, lace-cap flowers have round, flat flower heads.




An interesting quirk of hydrangeas is their ability to change colour in certain soils. This isn’t true for all types though and is usually seen in mophead and lacecap varieties of Hydrangea Macrophylia. The colour change is due to the PH of the soil which affects aluminium availability. Those with blue or pink flowers tend to be blue in acid soil conditions, mauve in acid to neutral soil conditions and pink in alkaline conditions. To get the best flower colour, choose plants that give the best colours for the soil type you have.

  • Blue & white hydrangeas like a low PH (below PH5) or you can plant them in lime-free compost e.g. Ericaceous Compost, Brown Gold.
  • Pink hydrangeas like a neutral to high PH (PH 7 – 9) or you can plant them in multi-purpose compost or into ordinary soil.

When should it be grown?

  • If transplanting a hydrangea, do it when it is dormant during the winter and all its leaves have fallen off
  • When buying hydrangeas, try to buy one that is in bloom so you can see the colour and what type of bloom it is.
  • You can plant anytime from spring onwards, after the last frosts.

Where should it be grown?

  • Hydrangeas love most, well-drained soil in a semi-shady part of the garden. Before you plant, work plenty of organic matter into the soil, like compost or well-rotted manure.
  • Avoid planting directly under a tree because the plant will be competing with the trees’ roots
  • Hydrangeas do well in a large pot or when planted directly into the ground.


Hydrangeas need very little care and they don’t ‘need’ to be pruned but they will get a bit scruffy if they are not pruned occasionally. There is an argument to say not to cut back your hydrangeas at all! They set their flowers in year 1 for year 2 so if you cut them back they won’t flower in the second year.

That said, regular pruning encourages new growth that can produce a better display so it is worth cutting out any unwanted broken or poor stems to tidy the plant. You can cut out one or two of the oldest stems at the base to encourage the production of new replacement growth. This new growth will give more flowers than the old.

Shrubby hydrangeas should be pruned in early spring, remove the spent blooms, cutting back to the first strong healthy pair of buds down the stem.

Climbing hydrangeas should be pruned after flowering in summer. Just remove any spent flower heads and tidy up any untidy shoots back to healthy buds.

Recommended Variety

The Purple Punk hydrangea is perfectly suited to the Irish climate and is very popular among gardeners. The Purple Punk has a long flowering period and is full of deep, rich purple colour. A hardy variett with good strong branches, they flower from July to September and are disease resistant. The Purple Punk is an ideal addition to any garden, be sure to call into your local GroMor centre and check out their range of high quality hydrangeas on offer.

Any other additional tips

  • Hydrangeas don’t need to be fed any more than once a year in late winter or spring. On rich soils it shouldn’t be necessary at all. Do keep the base of the plant well-mulched with compost, bark or chippings.
  • If your garden has light or sandy soil feeding is more likely to be beneficial.
  • Try to use rainwater to water hydrangeas because mains water supplies can affect the flower colour turning blue flowers mauve or pink.
  • Hydrangeas love water so don’t let them dry out (their name comes from the word ‘Hydro’ meaning water)
  • Feed pink hydrangeas with an All-purpose plant food for flowering plants e.g. Growmore or Miracle Gro
  • Feed blue hydrangeas with an lime-free Ericaceous feed e.g. Miracle Gro Ericaceous feed
  • There is a myth that burying old metal around a hydrangea will encourage pink hydrangeas to produce blue flowers. It doesn’t work!