Gardening with Diarmuid Gavin: Don't abandon old fashioned Rockeries
Rockeries may have gone out of fashion but that doesn't mean we should abandon their favourite plant
Published 07/02/2016 | 02:30
I started planning and building gardens in the late 1980s when the trend du jour in suburbia was rockeries. They evoked a hint of history, drama, mystery and fun. You could even incorporate streams and pools or add a set of plastic or concrete gnomes.
These structures had first become fashionable in Victorian times where huge examples graced the gardens of country estates, sometimes mimicking the shape of the Swiss Matterhorn mountain or even Japan's Mount Fuji.
In those great gardens they were carpeted with alpine species, surrounded by small stone chipping and set in the crevices between rocks.
By the 1970s and 1980s, tastes were changing. An English nurseryman and garden designer, Adrian Bloom, had popularised the use of plantations of heathers and dwarf conifers and us Irish took to using these plants with some gusto.
Carpeting borders with heathers or draping them through rockeries seemed sensible and handy - they covered ground, kept the weeding to a minimum and evoked thoughts of mystical hills. What's more, they shone brightly in purple, ruby and white colours during autumnal, winter, spring and summer months. The dwarf conifers acted as accent plants, and so many a miniature scene of the Wicklow hills was created.
Now gardening tastes have moved on to more rounded plant displays and recreations in miniature of naturalistic landscapes have been replaced by our desire for features such as barbecue areas and trampolines.
But let's not throw the baby out with the bath water and abandon heathers altogether. They are a wonderful species which are well suited to many parts of Ireland and have many useful qualities.
To start with, they are evergreen, low maintenance and extremely hardy - one only has to consider the exposure and battering from winds they withstand on mountains and moorlands. They are bee and butterfly (and bat!) friendly and suffer from few pests or diseases.
When grouped together, they remain a great choice as a low ground cover, helping to suppress weeds and creating a beautiful living tapestry throughout the year. Depending on your species choice, you could have a flowering heather in any month of the year.
The term heather actually refers to three types of plants - Calluna, Daboecia and Erica. Calluna (ling, Scotch heather) is the common heather, native to these isles, with small leaves.
By in large, it is summer flowering and prefers acidic soil. White heather is commonly associated with good luck and traditionally a bride would have a sprig tucked in their bouquet. Calluna 'County Wicklow' produces a delightful profusion of pink blooms, while 'Tib' has darker pink flowers.
The Irish heather is called Daboecia. Summer flowering, it also prefers acidic soil as many scavenging gardeners have found out when they've tried to dig it up from the hills and transfer to sometimes alkaline soils in the city and suburbs where it just hasn't been happy.
It has larger leaves with white underneath, and urn-shaped flowers (pictured above) in mauve to purple. Daboecia 'Bicolor' has purple and white flowers, and some flowers are striped with both colours.
Finally, Erica is the winter-flowering heather that you will see in bloom at the moment.
The really useful thing about Ericas is that some will tolerate neutral to alkaline soil. Generally these will be cultivars of Erica carnea, Erica x darleynesis and Erica vagans but always check the label to make sure what soil is appropriate. Of course you can always plant acid-loving plants in tubs and containers using ericaceous compost.
Not sure what pH your soil is? Soil testing kits are available and cheaply from your local garden centre and easy to use. A result of seven is neutral, anything below this number is acid and above it is alkaline.
When planting heather, set it deeply with lower foliage resting on ground, and about 2.5cm of stem under the soil. Informal drifts are best, and they look great on banks or mounded beds - but these should be south-facing.
If you are planning a heather bed, consider whether you want an explosion of colour all at once, or do you want a selection of species that will light up at different times of the year?
Maintenance is limited to annual pruning. Just lightly clip off the dead flowers and some stem but not back into old wood as heathers will not regenerate if hacked back. I would use a garden shears for this job as individual pruning with a secateurs would be very time-consuming.
For winter and spring flowering Ericas, do this after flowering in April. In the case of the summer-flowering Callunas and Daboecias, prune lightly in February or March. It is important to do this once a year to retain their bushy shape, otherwise they will become leggy and straggly-looking.
Propagation is by cuttings, seeds or layering but layering is probably the easiest for the gardener.