Hydrangeas have large blooms, which bring flamboyant colour to the garden in late summer and autumn. This year they are thriving due to the regular rainfall. They are easy to grow, dependable and they improve with age. Hydrangeas can be seen grown in the vast majority of gardens. They are true survivors and can be seen flowering in overgrown or neglected gardens. With a small amount of care they will really do well.
Grow hydrangeas in fertile, moist but well drained soil with compost added. Hydrangeas prefer dapple shade against a north or west-facing wall with some protection from cold winds, which burns the new foliage in spring. The flowers are likely to scorch if exposed to full sun. They need plenty of moisture during the summer.
The flowers come in a range of colours that include red, white, blue and various shades of pink. The flower colour depends on the cultivar and on the availability of aluminium in the soil, which is determined by the pH of the soil. On acid soils (pH 4.5-5.5) flowers may achieve intense deep blue colour, this changes to shades of pink as the soil pH increases. The blue colour flowers may be enhanced by a weekly application of blueing compound (aluminium sulphate). It may take a few years before the flower colour changes. Nurseries can grow perfectly blue hydrangeas in lime free compost but many of these will change to pink when planted in garden soil with some lime in it.
Pruning is not essential but may be done each spring as new shoots emerge. Since most hydrangeas flower on the previous years growth do not remove all of these shoots. Remove about a third of the older, less productive stems, cutting them back to ground level to encourage new shoots to grow from the ground. Leave old flowers heads on the shoots during the winter to give frost protection to the new delicate growth in spring. The old flower heads look fantastic when their brown papery domes are covered in frost. The flowers heads can be dried and sprayed with colour for winter decoration.
There are many cultivars of Hydrangea macrophylla (common hydrangea) producing red, pink and blue flowers that are either mophead or lacecap. Hydrangea paniculata produces beautiful cone-shaped flowers that are mostly white. There are several varieties of this shrub or small tree that can grow up to 20 feet tall. If pruned hard in spring it never gets out of hand and is ideal for the small garden. Hydrangea petiolaris is a climbing hydrangea, which will cover a shady wall, even a north facing wall, using its self-climbing shoots that attach themselves to the wall like ivy. It produces small white flowers that only last for a few weeks in summer and does not flower until the plant has matured. Hydrangea seemannii is an evergreen climbing plant that produces white flowers in summer.
Herbaceous plant of the week
Ligularia is grown for its large brownish green leaves that are deep purple underneath. In late summer the plant produces deep orange daisy like flowers on stems up to 3 feet tall. The plant will attract large amounts of butterflies. Grow the plant in moderately fertile moist soil in full sun with some midday shade. Ligularia ‘Desdemona’ is a popular variety. Slugs and snails may damage the new emerging leaves in spring.
Jobs for the week
In the greenhouse, plants like tomatoes, peppers, chillies and cucumbers will continue to produce a plentiful supply of fruit. Removing the ripe fruit will encourage the green fruit to ripen.
Plant strawberry runners and spring cabbage. Many vegetables are reaching maturity at this time of the year, these can be used as soon as they mature. Some of the vegetables that you cannot use can be frozen for use later in the year.
Buy spring-flowering bulbs, the quality and variety will be much better at this time of the year.
Garden Club Notices
Limerick Flower & Garden Club will be holding their first meeting after the summer break at the Greenhills Hotel on Tuesday September 8. Demonstrator for the night will be Ann Cooney.