Dwarf alpine shrubs have a place in every garden, however small. There are even some which are so diminutive and slow growing that you may be surprised to hear that they are shrubs at all. These can be used in alpine gardens, troughs or other containers. Dwarf shrubs can be evergreen or deciduous, upright, rounded or prostrate in form. Often carried on attractive stems their leaves are smooth, rough or hairy, in various colours. Some are so spiny that handling the plant can only be done painlessly when wearing gloves. But most important of all, many are free flowering with examples blooming in every month of the year, while some carry colourful berries that provide an invaluable feature in the winter garden, and others provide good autumn colour.
There is no universally acceptable definition of ‘dwarf shrub’ but I have excluded here any plant that does not have at least some permanent woody framework, or which is likely to exceed 1m in height within 10 years in most gardens. I have excluded dwarf conifers and heathers as there are excellent books and other sources of information devoted to them.
Some of these 14 dwarf shrubs for the alpine garden are not that easy to obtain. Nevertheless they are all available, and in my experience the search is often half the fun of growing new plants.
While most dwarf shrubs will thrive in any reasonable soil, some require more freely drained conditions than others; this is noted in the descriptions. I have assumed that it is common knowledge that most members of the rhododendron family (Ericaceae) will not thrive in limey (calcareous) soils. There are dwarf shrubs suitable for all exposures, from full sun to full shade.
Planting is generally best done in spring or autumn, although with pot grown specimens the rule nowadays, this is less important than it was when bare rooted stock predominated. Make sure to prepare the ground well, adding humus and/or drainage material if necessary, and take out good-sized planting holes that will accommodate the roots with ease. If the plant is ‘pot-bound’, tease out the roots with an old kitchen fork before planting as this will aid establishment. Water thoroughly and keep well-watered until the plant is clearly growing away.
Some of the more vigorous plants mentioned may need occasional pruning to keep them in bounds. This is generally best done just after flowering. In the case of, dense bushy kinds, do not be afraid to use the garden shears. Less vigorous sorts with a more defined structure are best pruned with secateurs.
Like all plants dwarf shrubs are occasionally attacked by pests and diseases, but this is rarely a severe problem. Aphids can quickly build up if not seen and dealt with, preferably without the use of toxic chemicals. Slugs and snails generally only cause appreciable damage on young shrubs. Diseases are generally even less of a problem, except perhaps mildews in cold damp weather.
For reasons of space, and availability of images, I shall describe particular species and cultivars. But in many cases there are equally good alternative selections. My advice is whenever possible to ‘see before you buy’ and choose what takes your fancy.
Everyone loves a daphne, principally because of the exquisite scent with which they raise even higher one’s appreciation of a stroll around the garden on a calm, early spring day. There are quite a few species, and many cultivars that you can grow if you can acquire them, for they are mostly difficult to propagate, slow thereafter, and therefore expensive. D. cneorum ‘Eximia’ is a very old selection of a species known in its alpine home as ‘Garland Flower’. It forms large, flattish mounds of twiggy stems, at the tips of which in April it produces clusters of mid to pale pink flowers. Daphnes are not difficult to grow, provided they have good soil drainage, but never dry out completely at the root. They do not generally appreciate being hard pruned or dug up, so treat them with the respect their celebrity commands.
A ground hugging broom with disproportionately large and imposing reddish keeled flowers, this is one of the joys of the alpine garden in April to May. Like all its kind, it likes the hottest, sunniest spot you can provide for it. Then it will thrive and be very long-lived. Plants are self-fertile, producing plenty of viable seeds in their flat, black pods. You may have to seek out this plant from a specialist alpine nursery, but the reward will more than justify the effort.
This is another member of the pea family, often known as blue broom or the blue hedgehog plant. It is also an alpine but occurring only in the Pyrenees, the Atlas Mountains in Morocco, and a few other locations skirting the Mediterranean. In the Atlas I have seen it in full and glorious bloom along high, exposed, shaley ridges harbouring few other plants. Erinacea anthyllis flowers at about the same time as the broom just described, and requires the same conditions. I have never had seed set on my plants, perhaps they are self-sterile. I have, however, rooted new shoots, taken before they harden into spines.
Few UK gardeners grow any of the New Zealand daisies (celmisias). Those who do mostly only try the robust, rosette forming species with large white daisy flowers on strong stalks, such as C. semicordata. Fine as they are, these are by no means the only growth forms in this fascinating genus. There is a number of choice, long-lived dwarf shrubs among them, grown chiefly for their structural and foliar interest rather than their flowers. Among the best is Celmisia hectorii. This has among the most silvery foliage of any shrub, the intensity seeming especially bright on dull winter days. Like all celmisias, this requires good water-retentive soil that never dries out. It is best to go over it every spring, removing dead leaves and any accumulated winter debris. Afterwards, top dress with fine composted bark mixed with sharp sand or fine grit, enriched with a little slow-release fertiliser.
For the purpose of this article I am treating myself to two dwarf rhododendrons from among the hundreds of species and cultivars available. Neither is particularly common, and you are unlikely to find them in the average garden centre, but both can be found and are well worth the trouble. (For a wider range of species and cultivars read my article on Rhododendron Choices for Small Gardens)
Rhododendron X ‘Augfast’ is a hybrid between the pale blue flowered and quite large growing R. augustinii, and the diminutive, very dark blue flowered R. fastigiatum. It has combined the merits of those two outstanding parents in a most satisfactory way. R. primulaeflorum is one of the dwarf Himalayan group of so-called ‘daphne-flowered rhododendrons’. It grows to about 1m high and wide in 15 years and unfailingly covers itself in long-lasting flowers. The foliage has an aromatic smell when brushed against, which some like and others refer to as ‘old tom cat’!
Most of the smaller rhododendrons are plants of open hillside habitats in the wild so prefer full sun to flower well, although quite deep shade is tolerated but with less spectacular results. Soil should be acid, with plenty of humus and gravel or sand for drainage. An occasional top dressing with gritty organic compost will keep the plants healthy. You can propagate dwarf rhododendrons from seed, but it is a slow and problematic process as the seed is dust fine. Cuttings should be of new season’s growth just as it has started to harden. They should root well, although it may be the following spring before some are ready to pot up. Rooted cuttings should flower within 2-3 years, a much shorter wait than for cuttings of larger rhododendrons.
The genus Menziesia has recently been moved into Rhododendron, but it is as Menziesia that you will probably find it in lists. Flowering at the same time as the bulk of the dwarf rhododendrons, these fellow members of the tribe are easily overlooked. But that would be a great shame as the flowers are exquisitely beautiful, with their hairy peduncles catching the light. They require the same conditions as dwarf rhododendrons but flower better in part shade. An added bonus is that they are deciduous and produce stunning autumn colour.
I have seen this prostrate member of the rhododendron family creeping over the woodland floor in Eastern N. American mixed forests, but unfortunately not in the ‘fall’ when the carpet of dark orange berries over lustrous evergreen foliage would surely be a wonderful sight. This is an easy ground cover plant for any acid to neutral soil. A semi-shaded site will suit it bests provided the soil does not dry out. The fruits should last from September until Christmas if left alone by birds and mice. Or you can eat them yourself, although they are a bit bitter to my taste.
I am not generally a fan of lilacs because out of flower they are ugly shrubs to my eyes. But the Korean lilac is altogether different – more refined to my biased view. It is a twiggy bush which will eventually require shearing back to keep it within our 1m limit. The flowers are very freely produced, not as strongly scented as some of the large-flowered garden cultivars, but sweet enough. Grow it in a sunny spot where the scent can be appreciated on a May evening. It is easy to root non-flowering cuttings at almost any time of the year.
Travelling back to the South Island of New Zealand we have Leucogenes grandiceps. Its flowers bear a striking resemblance to those of the much-loved edelweiss of the European Alps. Thus it is widely known as the ‘South Island edelweiss’. This is a plant of intermediate and higher elevations. There it occurs on rock outcrops, cliff faces, moraines and other rock strewn ground, generally in the open. In gardens it resents hot sun or humid conditions, preferring a position in cool, semi-shade. Propagation is easy by rooted offsets, fertile seed is rarely set in most UK gardens.
This low growing hebe species from the mountain slopes of the South Island of New Zealand is not often seen in gardens. However it is obtainable and is a very nice dwarf shrub for cultivation in the open garden or in a container. It will not exceed 30cm in height, spreading to 50cm across. Hebe raoulii is evergreen with small, red-edged, serrated leaves that set off the little cones of pinkish-mauve flowers well. It needs clipping back after flowering to keep it compact, but is long-lived and reliable in any sunny spot in well drained soil.
This firecracker of a plant will light up dull late summer and autumn days, but only where it is exposed to all the heat and light that can be provided in a North Wales garden. It spreads by runners, but these are easily removed if required. It is also a good wall plant, as seen on the terraces at Bodnant Garden in North Wales.
The dwarf rowan which you most often see in gardens is the orange fruited Sorbus reducta. This is an excellent plant, available in two forms, suckering and non-suckering, and it should be in every garden. Sorbus poteriifolia is less commonly seen but is available. This is very much worth seeking out. It is smaller than S. reducta and more densely foliaged, expanding gradually to cover perhaps 40cm in 10 years. The brilliant white fruit stand out well against the dark green foliage when first formed, and remain attractive as the leaves change to all shades of yellow and gold. You can propagate it easily either by taking off rooted pieces in spring, or from seed.
I am purposely ending this selection of some of my favourite dwarf shrubs (I could easily name a hundred more) with this diminutive true alpine evergreen because it flowers almost the whole year round. It does not exceed 20cm in height and will take several years to reach that dimension across. There is an equally attractive and easy form with dark pink pea flowers that has been given the varietal name ‘Rhodoptera’. Plant it in a fertile, quite rich soil, but with free drainage and it will steadily increase. It roots gently as it spreads; rooted pieces may be taken off as ‘Irishman’s cuttings’.
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