Rockery perennials is a vague term used by Irish landscapers to describe a dwarf herbaceous which is suitable for growing in a rock garden. Such plants are often referred to as alpines because many of them were originally collected from the slopes of the Hiyalayas, Andes, Atlas Mountains and so on. The Edelweiss of the Swiss Alps has become the classical representative of this group – for landscapers they are low growing and extremely hardy with a passion for sun and gritty, draining soil. Many true alpines can be grown outdoors as rockery perennials but some of the choicest examples have to be kept in an alpine house. The reasons why landscapers house these difficult plants indoors is that they cannot stand our winter winds, frosts and rain.
Not all rockery perennials are true alpines. Some that landscapers use come from lowland sites such as deserts and the seashore. A mixed bag then for landscapers in Ireland. In Ireland perennials are often grown in a rockery or rock garden. Success with a rock garden depends on proper sitings, construction, and planting.
Landscapers should pick an unshaded spot as nearly all perennials are sun lovers. A few require shade and these can be easily accommodated against a rock face which receives little or no sun during the day. A tip for landscapers is to never build a rockery beside a tree as the drip from the wet foliage in summer and the blanket of fallen leaves in winter can be fatal.
Having found the right site you must now think about construction. Order your stone – find a good supplier from your local town in Ireland. Maybe talk to professional landscapers and find out where they are sourcing their stones. This is always a good idea as you will find where the professionals get the best quality and value. You might be looking for slabs weighing between 50 and 250 pounds. A good type of stone for perennials in called tufa. It is a porous limestone which allows root penetration.
Landscapers should note that before you start lifting stones you must make sure that drainage is adequate. If there is the slightest problem you should build a soakaway of pebbles or broken bricks on which the rock garden should be constructed. Landscapers should always try to make the rock garden look like a natural outcrop with the stone slabs sloping gently backwards and with most of the bulk and all of the undersides buried in the earth. Cutting a rockery into a sloping lawn is the easiest situation although with care you can build one on a level site.
Landscapers should use a planting mixture rather than ordinary soil for building up the structure and for filling the gaps between the stones. Planting is the final stage but it would be a weak rock garden is you only used rockery perennials. Dwarf conifers, low growing shrubs, dwarf bulbs and a few annuals can all be added to your rock garden.
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