Growing Alpines
and Rock Garden Plants

These notes are written from a New Zealand gardener's point of view but we hope all gardeners will find them of interest.


HOMEPAGE

CATALOGUE - PAGE 1 - Plants A to G
CATALOGUE - PAGE 2 - Plants H to P
CATALOGUE - PAGE 3 - Plants Primula to W



	A choice member of the Bellflower family, Campanula fragilis	
	
       	

What are Alpine Plants?

ALPINES are plants growing at high elevations, above the tree line.
They include the taller plants of alpine meadows which are often grown in perennial borders.

In rock gardening usually only the smaller alpine plants (approximately 15-30cm high) are used. Many rock gardeners also include dwarf plants of suitable character and proportion from non-alpine areas, such as coastal North and South America, steppes, prairies and deserts, the mediterranean and north Africa, Australia and southern Africa.

The majority of rock garden plants like an open sunny position outside with good air flow and a moderately fertile soil. They are unlikely to thrive where the soil becomes arid in summer or where water will not drain freely away. Most will tolerate frost and snow but the foliage of some plants will be damaged by freezing if the leaves are saturated with water.


Androsace pyrenaica, a classic alpine of the Alps, perfect for growing in crevices A thoughtful selection of plants will provide you with colour for most of the year, perfume, berries and autumn foliage.

Plants can be cultivated in a variety of ways so whatever your circumstances you can enjoy growing these beautiful little plants, even if you live in an apartment and have just a balcony.

You work with what you have, maybe you have a flat site, or no access to rocks, maybe your budget is limited, or you are not as mobile as you once were. Work with what you have and create something beautiful.

Of course, not every gardener has a rock garden or is interested in creating one but the alpine plant world contains hundreds of delightful small perennials to grace any garden, whether it be paving, walls, the front of a sunny border, or accompanying woodland gems in shady corners.
rock garden

Rock Gardens for the Enthusiast

A rock garden is an arrangement of rocks in the open garden to provide a home for alpines and rock garden plants.
As well as the more traditional terraced type of rock garden made on a slope, very satisfactory arrangements can be constructed on flat ground.

Imagine river flats carpeted with colourful little rock plants, or a boulder field planted with alpines.


rock garden constructed on a flat site Select your site away from buildings for preference. Bear in mind that a position close to the sunny side of a house will radiate a lot of heat in summer and the garden may be in a rain shadow area. If close to established trees or large shrubs these are likely to take much of the rain and also compete for soil nutrients. Plants for such positions will need particular care in their selection.
With warmer summers becoming more common, gardeners in the drier areas of New Zealand might like to consider a south-facing rock garden position (here, south-facing is the cooler shadier aspect).
On a flat site the soil can be mounded up at least 40cm to improve drainage.

Rocks If possible choose rocks which are all of the same material, for example all sandstone (or schist, limestone, river boulders or squarish blocks etc.) Use the largest rocks you can handle comfortably, with smaller pieces added during construction. Set the stones in deeply for stability and slope the top of each stone back into the soil so that water will flow to the plants' roots rather than over the front of the rock.

Soil should drain freely. Additional very well-weathered cow manure or sheep manure pellets, compost, gritty river sand (like coarse sugar, not as fine as salt), and a dusting of dolomite lime dug in about two weeks before planting will all improve the soil.

Maintenance includes feeding in spring with a light sprinkling of dried blood and bone or balanced fertiliser around the plants, weeding, and removal of fallen leaves and a light trim back in autumn.


a dry stone wall planted with phloxes, aubrietia and trailing rosemary

Rock Plants are Perfect for Walls and Banks

Walls, in a gardening context, are structures made to retain a bank or soil, often built of stones, bricks or other materials, with crevices and channels which can be planted up with cushion or trailing plants. Good choices would be perfumed Dianthus, brightly flowered carpet Phloxes, trailing Gypsophila, Aubrietia and Alyssum. There are many evergreen carpeting varieties which will cover the ground and give year-round interest.




Patios, Terraces and Paving

Paving such as a terrace or paved path is just made for planting with little cushion plants and mats in the crevices between tiles or stones. Whether a formal or informal design these will tolerate light foot traffic - aromatic Thymes, perfumed small Dianthus, creeping Bellflowers (Campanulas)


view of a raised bed constructed of timber and filled with sand

Raised Beds are Popular

A raised bed is created with a low retaining wall built into a sloping piece of ground or a free-standing structure of low walls filled with soil, with rock garden plants on the top and sides.
It is a good option if you have physical limitations since the garden can be tended from a chair and plants and perfumes can be appreciated to the full without having to bend down.
Your choice of goodies for this garden is pretty much unlimited, although you probably won't want to plant it with varieties which are too vigorous and hog the space.

this hypertufa trough is planted with silver saxifragas using pieces of limestone for the stones

The Alpine Gardener's Special Love - Trough Gardens

A trough garden is a container filled with soil and planted up as a miniature rock garden. Usually movable depending on size and construction. These containers may be of stone, hypertufa (concrete with peat added), concrete, timber, metal or plastic.
Remember that with the latter two materials the heat of sun on the sides may damage the plant roots in contact with them. Troughs must have at least one drain hole, covered with mesh to deter insects.

You can site your trough in sun or part shade, with free-draining soils adjusted according to whether you want to grow plants preferring acid soils such as miniature Rhododendrons or some Primulas, or those which enjoy limy soils such as Dianthus, Saxifrages and Campanulas.

For a general soil mix try 5 parts good quality potting mix, 1 part loamy soil, 1 part sheep manure pellets, 1 part compost, 2 parts coarse river sand (no fine silty material). Add a dusting of dolomite lime to all mixes, even for acid-lovers. If mix is for lime-loving plants add crushed lime chip or an extra dusting of dolomite. For acid-loving plants substitute 1 part peat for the sheep pellets.


An example of crevice planting in a hypertufa trough Fill the trough completely with the soil mix (do not put large drainage material in the bottom) and mound it up to allow for settling. Set your selected stones on top.

Give the plants a good watering before and after planting and finish off with a top-dressing of small chips or stone which will be in harmony with the larger stones.

The fertiliser in most potting mixes is exhausted within a year so, as part of your spring routine, give your troughs a light dressing of your favourite general fertiliser or dried blood and bone.
A round hypertufa trough
rock garden

Pot Cultivation for those Special Plants

Growing alpine plants in pots is often the preferred method of cultivation for enthusiasts wishing to exhibit at their local show or at the New Zealand Alpine Garden Society's spring show in Christchurch.

It also allows close-up-and-personal cultivation of extra special, rare and demanding treasures which gives pleasure and satisfaction to the keenest grower.

Soils and conditions can be tailored to suit each plant. If in a cool greenhouse or shade house the pots can be plunged into damp sand to maintain a cooler root temperature during summer. Many gardeners enjoy growing their potted alpines outdoors, beside paths, steps and patios.

For those without a garden, pots are, of course, the perfect choice and can be moved from place to place.
rock garden

Growing in an Alpine House

Growing alpine plants in an alpine house enables management of overhead moisture in winter. Maximum ventilation along the walls is essential and also shade from mid-September until April in New Zealand. Plants are grown in pots on benches, or in raised beds in situ. Here again, plunging the pot into damp sand will keep the roots cooler in summer.

sand bed

Sand Beds - an Alpine Success Story

A sand bed is a method of growing alpine and rock garden plants in pure sand to avoid humus which might produce moulds and rots.
We have made two sandbeds which we filled with crushed river sand with the finest silty material removed. The particle size ranges from the size of coffee sugar up to that of rice. Both beds were completely filled with sand when in fact a depth of of approximately 40cm would have been sufficient. The beds are in full sun and the upper 15cm of sand gets hot and fairly dry in midsummer.

Planting was done during the cooler autumn and winter months to allow plant roots to establish before late spring. All potting mix was shaken from the plant roots and granulated or slow-release fertiliser worked into the sand at planting time.
From time to time in the height of summer we water the beds with a hose at dusk but the plants tolerate periods of no water with no trouble. Weeding is easily attended to and because the beds are in full sun we are not troubled with liverworts. Because of the rural setting and clear air there is a surface build up of lichens and sparse moss which I don't like.
sand bed We have tried plants from many countries in these beds and the most notable successes have been New Zealand alpines such as dwarf Pygmy Brooms (Carmichaelia), cushion Forget Me Nots (Myosotis) and Celmisia, Kelleria, dwarf Dracophyllum, Edelweiss (Leucogenes) and even Raoulia eximea (also called Vegetable Sheep). Eriogonums, Lewisia leana and dwarf Yucca from North America also provide a lot of character and recently planted Delospermas are giving colour in quantity. Silene bolanthoides has spread to make a fine mat and carries abundant flowers which perfume the evening air in summer.

This method of cultivation has much to recommend it as the plants stay in character, flower well and weeding, while not non-existent, is very easy.



HOMEPAGE

CATALOGUE - PAGE 1 - Plants A to G
CATALOGUE - PAGE 2 - Plants H to P
CATALOGUE - PAGE 3 - Plants Primula to W



Hokonui Alpines, Croydon Siding Road, R.D.6, Gore 9776, Southland,
New Zealand
Telephone,Fax 03 208 9609.
Email us: hokpines@actrix.gen.nz