The Scottish Garden Plant Award

Scotland’s very varied and particular climate suits a huge variety of plants, but there are a great many that do well further south but struggle in Scotland, because of lack of heat, winter wet or other factors; this includes many plants which have the RHS Award of Garden Merit (AGM). Conversely, many of the best performers in Scotland are not as happy further south – for example, many alpines, meconopsis, and Tropaeolum speciosum.

The most serious flaw with the AGM, from a Scottish perspective, is the RHS H4 hardiness rating. This is defined as ‘hardy throughout the British Isles’, but in reality many plants with this rating are simply not reliably hardy in colder/inland gardens in England, and many of them are tender in Scotland away from the coast. We decided therefore to create an additional rating for the hardiest plants, so we have created an H5 rating for plants, suitable for cold, inland and high altitude gardens.

The notion of a ‘Scottish Garden Plant Award’ grew from these issues. The RHS Plant Finder contains 70,000 plant names. In the face of so many plants on offer, we thought it would be useful to point gardeners in the direction of the most reliable, tried-and-tested plants, which are the best of their type for Scottish gardens. We hope that the award will be used on plant labels in Scotland to help gardeners make the best selection of an often bewildering range of plants.

To consider which plants should receive the award, we assembled an impressive group of judges, representing a wide spectrum of Scottish horticultural expertise. Sometimes there was agreement, sometimes not. We now have a list of 500 plants that have been awarded the Scottish Gardenplant Award or SGA. Their hardindess ratings H1-H5 are included. You can be sure that plants listed here with the SGA symbol are a very good starting point for gardeners from one end of Scotland to the other. The list of Scottish Gardenplant Award plants is also available on Glendoick Gardens (www.glendoick.com)  

Ken Cox

Astilbe 'Sprite' (simplicifolia hybrid)

Astilbe 'Willie Buchanan'

Astrantia major 'Claret'

Astrantia major 'Ruby Wedding'

Bergenia 'Bressingham White'

Bergenia cordifolia 'Purpurea'

Bergenia 'Silberlicht'

Brunnera macrophylla

Brunnera macrophylla Jack Frost'

Caltha palustris

Caltha palustris 'Alba'

H5

H5

H5

H5

H3-4

H4

H4

H4

H4

H5

H5

Lonicera japonica 'Halliana'

H5

Lonicera nitida 'Baggesen's Gold'

H4

Lonicera periclymenum 'Belgica'

H4-5

Lonicera periclymenum 'Graham Thomas'

H4-5

Lonicera periclymenum 'Serotina'

H4-5

Magnolia stellata

H4-5

Magnolia stellata 'Waterlily'

H4-5

Magnolia 'Susan'

H4-5

Magnolia wilsonii

H4-5

Mahonia x media 'Charity'

H4

Olearia x haastii

H4

Caltha palustris 'Flore Pleno' (d) needs boggy soil

Campanula carpatica Blue Clips/Blau Clips

Campanula glomerata 'Superba'

Campanula lactiflora 'Alba'

Campanula lactiflora 'Loddon Anna'

Campanula lactiflora 'Prichard's Variety'

Campanula lactiflora 'Superba'

Campanula portenschlagiana

Cardamine pentaphylla

Celmisia semicordata

Convallaria majalis

Coreopsis grandiflora 'Early Sunrise'

H5

H5

H5

H5

H5

H5

H5

H5

H5

H3-4

H5

H4

Osmanthus delavayi

H4

Pachysandra terminalis 'Green Carpet'

H4

Pachysandra terminalis 'Variegata' (v)

H4

Paeonia ludlowii (P. lutea var ludlowii)

H4-5

Parrotia persica

H4

Parthenocissus quinquefolia

H5

Parthenocissus tricuspidata

H5

Philadelphus 'Beauclerk'

H5

Philadelphus 'Belle Etoile'

H4-5

Philadelphus 'Manteau d'Hermine' (d)

H4

Philadelphus 'Virginal'

H5

Phormium tenax

H3

Corydalis cashmeriana

Corydalis flexuosa

Corydalis flexuosa 'China Blue'

Crambe cordifolia

Crocosmia × crocosmiiflora 'Solfatare'

Crocosmia 'Lucifer'

Cyananthus lobatus

Cynara cardunculus

Dactylorhiza elata

Dactylorhiza foliosa

Dianthus alpinus

Dianthus deltoides

Dianthus 'Inshriach Dazzler'

Dianthus 'Little Jock'

Dianthus 'Mrs Sinkins'

Dicentra 'King of Hearts'

Dicentra spectabilis

Dicentra spectabilis 'Alba'

Dicentra 'Stuart Boothman'

H4

H5

H5

H4

H3-4

H4

H4

H3-4

H4

H4

H4

H4

H4

H4

H4

H4-5

H4

H4

H5

Photinia x fraseri 'Red Robin'

H3-4

Pieris 'Flaming Silver' (v)

H4

Pieris 'Forest Flame'

H4

Pieris japonica 'Little Heath' (v)

H5

Pieris japonica 'Mountain Fire'

H5

Potentilla fruticosa 'Abbotswood'

H5

Potentilla fruticosa 'Daydawn'

H5

Potentilla fruticosa 'Elizabeth'

H5

Potentilla fruticosa 'Red Ace'

H5

Prunus laurocerasus 'Otto Luyken'

H4-5

Pyracantha Saphyr Rouge = Cadrou' (PBR)

H4

Rhododendron 'Blue Tit' (Major Form)

H4-5

Rhododendron 'Christmas Cheer'

H4-5

Rhododendron 'Curlew'

H4

Rhododendron 'Fastuosum Flore Pleno' (d)

H5

Rhododendron 'Gibraltar' (A)

H5

Rhododendron 'Ginny Gee'

H5

Rhododendron 'Gomer Waterer'

H5

Rhododendron luteum (A)

H5

Digitalis × mertonensis

Digitalis grandiflora

Echinops ritro L.

Epimedium × perralchicum 'Frohnleiten'

Epimedium × rubrum

Epimedium × versicolor 'Sulphureum'

H4

H4

H4

H4

H4

H4

Rhododendron 'Nobleanum'

H4-5

Rhododendron 'Praecox'

H4

Rhododendron 'Ptarmigan'

H4

Rhododendron 'Ramapo'

H5

Rhododendron yakushimanum

H5

Rhus typhina

H5

Epimedium grandiflorum

H4

Erinus alpinus

H4

Ribes sanguineum 'Pulborough Scarlet'

Eryngium × oliverianum

H4

Salix 'Boydii' (f)

Eryngium alpinum

H4

Salix hastata 'Wehrhahnii' (m)

Eryngium bourgatii 'Graham Stuart Thomas'

H4

Salix lanata

Eryngium bourgatii Pico's Blue'

H4

Salix reticulata

Eryngium giganteum 'Silver Ghost'

H4

Skimmia japonica 'Rubella' (m)

Euphorbia amygdaloides var. robbiae

H4

Spiraea nipponica 'Snowmound'

Euphorbia characias subsp. wulfenii

H4

Syringa meyeri 'Palibin'

Euphorbia griffithii 'Dixter'

H4

Syringa vulgaris 'Madame Lemoine' (d)

Euphorbia griffithii 'Fireglow'

H4

Viburnum davidii (m & f)

Euphorbia myrsinites

H4

Viburnum plicatum f. tomentosum 'Mariesii'

Euphorbia polychroma

H4

Viburnum tinus 'Eve Price'

Gentiana acaulis

H5

Viburnum x bodnantense 'Dawn'

Gentiana asclepiadea

H5

Vinca major 'Variegata' (v)

Gentiana septemfida

H5

Vitis coignetiae

Gentiana sino-ornata

H4

Weigela florida 'Foliis Purpureis'

Geranium (Cinereum Group) 'Ballerina'

H5

Weigela 'Florida Variegata' (v)

Geranium × oxonianum 'Wargrave Pink'

H5

Yucca filamentosa

Geranium × riversleaianum 'Russell Prichard'

H5

Geranium 'Ann Folkard'

H5

Ra=rambler

Geranium clarkei 'Kashmir White'

H5

Fl= Floribunda

Geranium dalmaticum

H5

S=Shrub

Geranium himalayense 'Gravetye'

H5

CL=Climber

Geranium 'Johnson's Blue'

H5

HT=Hybrid T

H5

H5

H5

H5

H5

H5

H5

H5

H5

H4

H4

H4

H4

H5

H4

H5

H5

H4

Ribes sanguineum 'King Edward VII'

Geranium macrorrhizum 'Album'

H5

Geranium macrorrhizum 'Ingwersen's Variety'

H5

Geranium phaeum

H5

Geranium psilostemon

H5

Geranium renardii

H5

Geranium sanguineum var. striatum

H5

Geranium wallichianum 'Buxton's Variety'

H5

Geum 'Lady Stratheden'

H4

Geum 'Mrs J. Bradshaw'

H4

Glaucidium palmatum

H4

Gunnera manicata

H3

Gypsophila repens

H4

Hacquetia epipactis

H4

Helenium ‘Wyndley’

H4-5

Helenium 'Moerheim Beauty'

H4

Helleborus × orientalis hybrids

H4-5

Helleborus × sternii Blackthorn Group

H3-4

Helleborus argutifolius

H4

Helleborus foetidus

H5

Helleborus niger

H4-5

Hemerocallis 'Stella d'Oro'

H4-5

Hepatica nobilis

H4-5

Hepatica transsilvanica

H4-5