When it comes to creating an alpine garden, you can easily do so in the smallest of outdoor spaces provided you have sufficient sunlight. You don’t even need to have the right type of garden soil as these charming, colourful plants can be grown in containers enabling you to provide them with the perfect growing conditions. Alpine gardens give you the perfect opportunity to have a colourful garden – but in miniature.
Originating from mountainous regions, growing in meadows, rocky screes, and rock crevices, alpines are cold-hardy but are very susceptible to winter wet if they do not have suitable drainage. The soil in their natural habitats is often made up of rock fragments, with only a small amount of organic matter from dead plants, and so retains few nutrients or little water. Therefore, in order to successfully grow alpines in Oxfordshire, you will need to modify the soil to ensure satisfactory drainage.
If you have clay soil which retains moisture for long periods you will certainly have to opt for containers or build suitable raised beds or even a rockery. You could also create sand beds using horticultural or sharp sand with a coarse gritty texture: concreting sand is a suitable alternative but do not use builder’s sand or beach sand as both are too fine and can easily be compacted leading to poor drainage. Planting in sand is particularly effective when we are experiencing months of heavy rainfall as it is free draining.
If you decide to plant in containers or troughs, both need to be raised off the ground and have drainage holes. Further, it is worth moving the container into the rain-shadow of a wall over winter, so it doesn’t get too wet. Bear in mind, container plants will need repotting every few years into fresh soil to keep the plants and their roots healthy.
Use a potting mix of 50:50 soil-based compost, such as John Innes No 1 or 2, mixed with horticultural grit or sharp sand. Cover the container’s drainage holes with single pieces of broken terracotta crock or use a fine mesh over the hole to prevent compost from clogging the drainage holes – but do not create a drainage layer as this is now considered ineffective as it can create a perched water table, unsuitable for alpine plants. If, however, you are creating raised beds filled with sand, it is worth adding a permeable membrane at the base before planting to stop earth worms bringing soil into the sand over time.
Alternatively, if space permits you may consider building a rock garden using a variety of large and small rocks. If you have a sunny slope this would be a perfect site for a natural looking rock garden.
Once you have planted your alpines, whether that is in a container or in the ground, apply a top dressing of coarse grit or 10mm of gravel around the plants. This helps to keep foliage off damp ground, preventing rot and will also act as a weed suppressant.
When it comes to choosing which plants to grow, most alpines are perennials but you can also find bulbs and dwarf shrubs. Once planted, they are usually grown as a collection which will over time form a tapestry of colour and textures.
SELECT YOUR PLANTS BASED ON A NUMBER OF THEIR CHARACTERISTICS:
Size: many alpines are compact, low-growing plants, but some grow taller. Choose plants which offer a variation in height to create interest.
Style of growth: depending on the size of the area you are planting, consider the plants growth habit. Some will form mound-like cushions whilst others will form cascading clumps or, as in the case of small shrubs and bulbs, may offer an upright growth habit.
Flower colour: many alpines have bright colourful flowers. Ensure your collection flowers at different times of the year to spread colour across the months and combine colours which work well together.
Foliage: as with most plants, it is important to look for interesting foliage, so when the plants are not flowering their leaves add interest and texture. You will find both evergreens and deciduous plants, some have variegated leaves, others silvery or downy leaves.
TOP EASY ALPINES:
Often when we visit a garden centre, we will pick up a range of small plants without realising we are actually buying alpines: herbs such as thyme and origanum can also be used. Amongst the easiest to grow are spring flowering Arabis (Rock Cress) and mat forming Aubretia which spills over rocks and is available in a range of purples, blues, pink and white. Usually flowering around Easter time, Pulsatilla vulgaris (Pasque flower) can grow up to 45cm tall.
Saxifraga (Saxifrage) is also perfect for shadier planting areas. Enthusiasts can see these plants along with other alpines at Waterperry Gardens where they have a noteworthy collection.
Fragrant Dianthus (Pinks) with their grey-green foliage start flowering from May onwards and provided they are deadheaded will continue to bloom all summer. These can be contrasted with Campanulas (bellflowers) which are available in various shades of white, blue and pink.
You may have seen Armeria maritima (Sea Thrift) growing on coastal pathways whilst on holiday but these plants are perfect for the edges of your alpine planting area. Another interesting collection of plants are the Sempervivum (Houseleeks) which are evergreen succulents, perfect for dry areas and containers.
Iberis sempervirens (perennial candytuft) is a wonderful low-growing shrub you could include. It grows to 30cm high and spread to up to 60cm if not pruned back; it produces pure white flowers in spring and can look spectacular. Conversely, Helianthemum (rock roses) are excellent for alpine gardens because they are low-growing, drought-tolerant, sun-loving shrubs that produce masses of colourful, saucer-shaped flowers, thriving in the well-drained, fertile, neutral-to-alkaline soil typical of rockeries. These are ideal for trailing over walls or creating groundcover on sunny slopes.
There are also a number of spring bulbs you can plant in an alpine garden including cyclamen coum, snowdrops, iris, crocus, various dwarf daffodils and anemone nemorosa (Wood Anemone).
If you’d like to learn more about growing alpines, consider becoming a member of the Oxford & District Alpine Society which meet monthly from September to April at the Exeter Hall, Kidlington. For further information contact celia.sawyer@btinternet.com.
