Rock gardens: plants

Although considered a specialised and 'difficult' area of gardening, there is a huge range of plants available for including in a rock garden, including many well within the capabilities of ordinary gardeners.

Edraianthus pumilo on tufa rock

Edraianthus pumilo on tufa rock

Introduction

With rock garden plants thriving in extreme altitudes, it is useful to know those that will live happily in our gardens. Most garden centres have a limited range of rock plants and alpines, so it is worth digging a bit more deeply to source some slightly lesser known, but suitable plants that will complement the investment in stone and labour it took to create the rock garden in the first place.

Practical considerations

When deciding on your shortlist of alpines;

  • Consider making a plan before visiting the nursery, so the plants are well matched to the conditions you are offering
  • Plant all the suggested plants in open, sunny sites with good drainage and reasonably fertile soil
  • Most shrubs in time grow too large for smaller rock gardens, but a few are sufficiently slow-growing or compact to be considered
  • Allow enough room for plants’ growing habits and plant in groups so as to avoid a ‘bitty’ look
  • Be wary of conifers unless they are miniature, as opposed to dwarf (which, ultimately does not mean small, but very slow growing - they will become quite large in time)

Suitable plants

The following list includes some of the more attractive and reliable plants for providing interest in different seasons from the many plants which can be grown in smaller rock gardens.

The flowering periods of some plants listed for spring, summer or autumn may overlap but their main period of interest is the one given under each seasonal category.

For a quick guide, take a look at our 10 AGM alpines with impact.

Spring flowering

Evergreens

Cassiope ‘Edinburgh’ AGM, C. mertensiana var. gracilis, C. ‘Muirhead’ AGM (cool, moist, acidic soil, humus-rich)
Daphne cneorum, D. collina, Daphne tangutica Retusa Group
Euphorbia myrsinites AGM
Rhododendron impeditum AGM, R. hanceanum Nanum Group, R. ‘Chikor’ (moist acidic soil, humus-rich)
Gentiana acaulis AGM, G. verna
Iberis sempervirens AGM

Deciduous

Alyssum serpyllifolium
Arabis ferdinandi-coburgi, A. procurrens ‘Variegata’ AGM
Arenaria balearica (cool, moist conditions)
Draba aizoides, D. rigida var. bryoides
Hacquetia epipactis AGM (light shade)
Oxalis adenophylla AGM, O. enneaphylla AGM
Primula rosea AGM (cool and moist)
Pulsatilla vulgaris AGM
Soldanella alpina (shade, cool, leafy soil)

Summer flowering

Evergreens

Armeria juniperifolia AGM, A. maritima
Andromeda polifolia,
A. polifolia ‘Compacta’ AGM (moist acid soil)
Artemisia schmidtiana ‘Nana’ AGM
Dianthus alpinus AGM, D. deltoides AGM, D. gratianopolitanus AGM, D. ‘Little Jock’
Dryas octopetala AGM, D. octopetala ‘Minor’ AGM
Hebe buchananii ‘Minor’, H. ‘Youngii’
Helianthemum ‘Amy Baring’ AGM, H. ‘Henfield Brilliant’, H. ‘Mrs C.W. Earle’ AGM,
H. lunulatum, H. oelandicum ssp. alpestre
Lewisia cotyledon AGM (shade, in vertical rock crevices)
Lithodora diffusa ‘Grace Ward’ AGM, L. diffusa ‘Heavenly Blue’ AGM (acid soils only)
Phlox douglasii, P. subulata
Primula auricula (not show auriculas),
Ramonda myconi AGM (full shade, north-facing rock crevice)
Saxifraga (many, some best in part shade)
Sempervivum (many)

Deciduous

Achillea clavennae, A. × lewisii ‘King Edward’ AGM, A. erba-rotta ssp. rupestris
Aethionema ‘Warley Rose’ AGM 
Alyssum spinosum ‘Roseum’ AGM
Anacyclus pyrethrum var. depressus
Androsace carnea
, A. lactea, A. lanuginose AGM, A. sarmentosa
Antennaria dioica, A. parvifolia
Anthemis marschalliana
Asperula lilaciflora 
Astilbe chinensis var. pumila AGM (moist soil)
Campanula ‘Birch Hybrid’ AGM, C. chamissonis, C. cochlearifolia AGM
Cyananthus lobatus, C. microphyllus AGM
Diascia cordata, D. barberae ‘Ruby Field’ AGM
Edraianthus pumilio AGM
Erigeron aurantiacus
Erinus alpinus AGM
Erodium reichardii
Euryops acraeus AGM
Felicia rosulata
Geranium (Cinereum Group) 'Ballerina' AGM, G. dalmaticum AGM, G. sanguineum var. striatum AGM 
Globularia cordifolia AGM 
Gypsophila repens ‘Dorothy Teacher’ AGM
Hypericum olympicum 
Leontopodium alpinum 
Linaria alpina 
Linum suffruticosum
subsp. salsoloides ‘Nanum’
Lychnis alpina
Lysimachia nummularia 'Aurea' AGM
Penstemon pinifolius AGM, P.laetus var. roezlii
Persicaria affinis

Phuopsis stylosa 
Platycodon grandiflorus AGM
Potentilla nitida, P. × tonguei AGM 
Primula frondosa AGM (semi-shade), Primula pedemontana, P. rosea AGM, P. ‘Wanda’ AGM (all moist, cool, leafy/peaty conditions)
Sagina subulata ‘Aurea’
Saponaria ocymoides AGM 
Sedum cauticola AGM, S. middendorffianum, S. spurium
Silene acaulis, S. schafta AGM
Veronica prostrata AGM, V. ‘Shirley Blue’ AGM, V. wormskjoldii

Autumn flowering

Evergreen

Gentiana × macaulayi AGM, G. sino-ornata AGM (moist, fertile, acid)
Colchicum cilicicum, C. kotschyi
Crocus kotschyanus
AGM, C. speciosus AGM 
Cyclamen hederifolium (moist, leafy soil; sun or semi-shade)
Sternbergia lutea, S. sicula
Zauschneria californica
(sheltered, sunny)
Zephyranthes candida (full sun, sheltered, milder areas)

Early winter flowering:

Crocus laevigatus

Centenary Crevice Garden at Wisley

Below is a selection of plants you can find in Wisley’s Centenary Crevice Garden;

Aethionema capitatum
Alyssum stribrnyi

Anagallis monellii AGM
Androsace bulleyana
Aquilegia laramiensis
Astragalus utahensis
Benthamiella patagonica
Campanula betulifolia
AGM 
Campanula 'Joe Elliott' AGM
Corydalis solida 'Firecracker'
Crepis incana AGM
Cyananthus lobatus giant
Cyclamen cilicium AGM
Daphne × hendersonii 'Kath Dryden'
Dianthus 'Dainty Dame' AGM 
Erigeron aureus 'Canary Bird' AGM
Gentiana 'Shot Silk'
Hepatica nobilis AGM 
Hypericum olympicum AGM
Moltkia petraea
Olsynium douglasii AGM 
Polygala chamaebuxus AGM
Primula 'Rachel Kinnen’
Rhododendron sargentianum
Saponari
a 'Bressingham' AGM
Sempervivum giuseppii AGM
Silene alpestris 'Flore Pleno' AGM
Tecophilaea cyanocrocus AGM 
Thymus serpyllum 'Pink Chintz' AGM
Vitaliana primuliflora
Zaluzianskya 'Orange Eye'

Links

RHS Find a Plant
Results from RHS Plant Selector for plants with an alpine habit


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