Top 50 Acid-Tolerant

Garden plants you can grow in the UK in acidic soil to help our pollinating insects

List Curated by Thomas McBride From research data collected and collated at the National Botanic Garden of Wales

NB: Butterflies and Moths are not studied at the NBGW so any data on nectar plants beneficial for them is taken from Butterfly Conservation What are Acid-tolerant Plants? All soil has a natural pH factor which determines the type of plants that can be grown in it. Most garden soils are neutral (pH 6.5-7) and are suitable for most plants; as long as other requirements are met. A small area of Britain has alkaline soil (pH 7.5-8) but the majority of areas that do not have neutral soil have mild to strongly acidic soils with a pH of between 5 and 6. These areas are often in the uplands such as the Brecon Beacons or near to heathland. In areas of moderate to strongly acidic soil, and soil may have to be partially neutralised in order to plant a wide variety of plants. If this is not possible, or you are particularly interested in growing plants that favour acidic

NB: many Hydrangea soil, this list should cover you. macrophylla cultivars How do I know if a plant is acid-tolerant? turn blue in acidic soil! Determining whether or not a plant is acid-tolerant from its appearance is nigh-on impossible. However, there are particular families to look out for. This list can definitely be used as an initial guide but there are lots of possible plants out there. When making soil more acidic or growing with acidic soil, you might add ericaceous compost. Ericaceous means acidic but comes from the heather flower (Erica). All plants in the Ericaceae family are acid- tolerant, most are acid-loving, so this is a great place to begin. Moorlands are acidic which can be shown by the wildflowers being predominately heather. Many shrubs are acid-tolerant such as members of the Hydrangea family, Magnolia family and Viburnum family. The Currant family, Grossulariaceae, is also acid-tolerant so these are a must if you are looking to grow edibles. Finally, there are only a few herbaceous plants that are acid-tolerant but try the poppy family, buttercup family and daisy family. Make sure to research each plant beforehand to be sure! Map Maps depict the native area of the plant (in green) Guide to using these pages: They also show areas the plant is naturalised (in purple)

Latin Binomial All maps shown Name are derived from ‘Plants of the Common World Online’; English courtesy of Kew Name Gardens

Flowering Period Photograph (this is when it is good of the plant for pollinators!) in flower

Plant Family

Insect groups known to Growing habit favour the and mature size nectar of this of the plant plant

Useful knowledge or warnings about the plant RHS AGM cultivars of this species (or a related species occasionally) i Key to these Pages Warnings

Additional information on these garden plants

This plant would The flowers only be suitable for and/or leaves meadow-style have a Pleasant Plant tissue is highly planting scent toxic if ingested

The plant has edible parts that are Sap may cause irritation Plant is often used in commonly eaten or (Wash hands after touching traditional Herbal Remedies used in cooking or avoid touching)

ii Temperature RHS Hardiness Scale

Some of the plants listed in our Top 200 are not fully H1a - Above 15ºC hardy in all or some parts of the United Kingdom. H1b - Minimum 10ºC Plants without a thermometer symbol are fully hardy in the severest UK Winter; equating to H5 or hardier. H1c - Minimum 5ºC Plants with a coloured thermometer symbol are hardy to varying degrees as follows: H2 - Minimum 1ºC

H3 - Minimum -5ºC

H4 - Minimum -10ºC

H5 - Minimum -15ºC Almost Hardy Half-Hardy Not Frost Hardy Not Hardy (H4) (H3) (H2) (H1) iii Pollinators Our data on pollinators has been collected from studies spanning over a decade. Pollinator symbols appear when plants are proven to be good nectar (a) (b) plants for certain insects. It should be noted that all bee and hoverfly data is ours but lepidoptera data is taken from Butterfly Conservation.

Our data spans a wide range of different insect species. For simplicity, these species have been condensed into six easy icons to represent them: (c) (d) a) Honeybees c) Bumblebees e) Moths b) Hoverflies d) Butterflies f) Solitary Bees (Includes Moths)

(e) (f) iv Actinidia chinensis Golden Kiwi

China

- None - Spring .

Actinidiaceae Kiwi Family

10ft+ Climber

Photograph from Flickr (CC) Manuel M. V. & Ting Chen (Flower) 1 N. America & Andromeda polifolia Eurasia Bog-rosemary

‘Compacta’ Mid Spring - Early Summer ‘Macrophylla’

Ericaceae Heather Family

Small Shrub

Photograph from Flickr (CC) Kerry Woods Acidic Marsh 2 Anemone hupehensis var. japonica Japanese Anemone

East Asia

‘Pamina’ Summer . ‘Rotkäppchen’

Ranunculaceae Buttercup Family

3ft Perennial

Photograph from Flickr (CC) Sen Itto 3 Arbutus unedo Mediterranean & Ireland Strawberry Tree

‘Atlantic’ Autumn . f. rubra

Ericaceae Heather Family

Small Tree

Photograph from Wikipedia (CC) Umberto Ferrando, Markus Nolf (fruit) 4 Berberis darwinii S. America Darwin’s Barberry

- Species - Spring . x media (Hybrid with B. empetrifolia) Berberidaceae Barberry Family

Medium Shrub

Photograph from Flickr (CC) Harry McGregor 5 Calluna vulgaris Eurasia Common Heather

‘Dark Beauty’ Early Summer - Early Autumn ‘Spring Cream’

Ericaceae Heather Family

Small Subshrub

Photograph from Flickr (CC) Andreas Rockstein 6 Camellia japonica Japanese Camellia

East Asia

‘Hagoromo’ Spring . ‘Pink Perfection*’

Theaceae Tea Family

Medium Shrub

* Fully double flowered cultivars are not good for pollinating Photograph from Flickr (CC) Eric Hunt insects so try to buy single flowers (see photo) when7 possible. Ceanothus arboreus California Island Californian-Lilac

‘Autumnal Blue’ Mid Spring - Early Summer ‘Trewithen Blue’

Rhamnaceae Buckthorn Family

Small Tree

* This plant will not survive below -10’c night temperatures, protect from very harsh winter nights Photograph from Flickr (CC) Eliot Phillips, Johnson Earls (Close-up) 8 Ceanothus thyrsiflorus N. America Blueblossom Californian-Lilac

‘Mystery Blue’ Mid Spring - Early Summer var. repens

Rhamnaceae Buckthorn Family

Medium Shrub*

* This plant will not survive below -10’c night Photograph from Flickr (CC) Kirt Edbom temperatures, protect from very harsh winter nights *C. thyrsiflorus var. repens is a climbing version. 9 Other cultivars are generally more shrub-like in habit. N. America & Cornus canadensis East Asia Creeping Dogwood

None Late Spring - Early Summer

Cornaceae Dogwood Family

1ft Perennial

Photograph from Flickr (CC) Kerry Woods 10 Cornus sanguinea Europe Common Dogwood

‘Magic Flame’ Summer . ‘Anny’s Winter Orange’

Cornaceae Dogwood Family

Large Shrub

Photograph from Flickr (CC) Andreas Rockstein 11 Daboecia cantabrica Europe St. Dabeoc’s Heather

‘Silverwells’ Early Summer - Mid Autumn ‘Waley’s Red’

Ericaceae Heather Family

Small Subshrub

Photograph from Flickr (CC) Mercedes Blanco 12 Enkianthus perulatus Dodan-tsutsuji

East Asia

- Species - Spring .

Ericaceae Heather Family

Medium Shrub

Photograph from Flickr (CC) Ume Y 13 Erica arborea Afro-Eurasia Tree Heather

*

var. alpina Spring . ‘Estrella Gold’

Ericaceae Heather Family

Medium Shrub

* This plant will not survive below -10’c night Photograph from Flickr (CC) Tim Waters temperatures, protect from very harsh winter14 nights Erica carnea Europe Winter Heather

‘Eva’ ‘Vivellii’ Mid Winter - Early Spring ‘Winter Snow’

Ericaceae Heather Family

Small Subshrub

Photograph from Flickr (CC) Maja Dumat 15 Fragaria x ananassa N. America S. America Garden Strawberry Fragaria virginiana x Fragaria chiloensis

Fragaria Fragaria virginiana chiloensis

Spring . ‘Cambridge Fav.’ ‘Rhapsody’ Summer . (Berries)

Rosaceae Rose Family

2ft Trailing Annual

Photograph from Flickr (CC) Maja Dumat 16 Grevillea rosmarinifolia Australia Rosemary-leaved Grevillea

East Asia

- Species - Midwinter - Early Summer ‘Canberra Gem’ (Hybrid with G. juniperina)

Proteaceae Protea Family

Small Shrub

Photograph from Flickr (CC) Richard Lane 17 Hamamelis mollis Chinese Witch-hazel

China

‘Jermyns Gold’ Mid Winter - Early Spring ‘Wisley Supreme’

Hamamelidaceae Witch-hazel Family

Large Shrub

Photograph from Flickr (CC) Wendy Cutler 18 Hemerocallis fulva Orange Daylily

East Asia

‘Cayenne’ Summer . ‘Selma Longlegs’

Asphodelaceae Asphodel Family

3ft Perennial

Photograph from Flickr (CC) Thomas Cizauskas 19 Hydrangea aspera Rough-leaved Hydrangea

East Asia

‘Anthony Bullivant’ Midsummer - Early Autumn ‘Peter Chappell’

Hydrangeaceae Hydrangea Family

Medium Shrub

Photograph from Flickr (CC) Steve Law 20 Hydrangea macrophylla Large-leaf Hydrangea

Japan

‘Hanabi’ ‘Zorro’ Summer . ‘Quadricolour’

Hydrangeaceae Hydrangea Family

Medium Shrub

Photograph from Flickr (CC) CyprusPictures 21 Hydrangea quercifolia Oak-leaved Hydrangea

N. America

‘Snow Queen’ Summer . ‘Snowflake’

Hydrangeaceae Hydrangea Family

Medium Shrub

Photograph from Flickr (CC) J Biochemist 22 Europe & Ilex aquifolium N. Africa European Holly

Spring . ‘Amber’ ‘Argentea’ ‘Golden Queen’ A/W (Berries)

Aquifoliaceae Holly Family

Medium Tree

Photograph from Flickr (CC) Randi Hausken, Bjorn S(Flowers) 23 Kalmia latifolia N. America Mountain-laurel

‘Freckles’ Mid Spring - Early Summer ‘Pink Charm’

Ericaceae Heather Family

Medium Shrub

Photograph from Flickr (CC) Nicholas A. Tonelli 24 Lamprocapnos spectabilis Bleeding Heart

East Asia

- Species - Mid Spring - Early Summer ‘Alba’ ‘Valentine’

Papaveraceae Poppy Family

2ft Perennial

Photograph from Flickr (CC) Mark Wordy 25 Magnolia acuminata N. America Blue Magnolia, Cucumbertree

Related Hybrids: ‘Elizabeth’ Spring . ‘Gold Star’* Magnoliaceae Magnolia Family

Medium Tree

*The species can vary between very blue (such as cultivar ‘Blue Opal’) or very yellow (such as the hybrids listed). Photograph from Trees & Shrubs Online (CC) Tom Christian 26 Magnolia campbellii Campbell’s Magnolia

East Asia

‘Darjeeling’ Spring .

Magnoliaceae Magnolia Family

Medium Tree

* This plant may not survive below -10’c night Photograph from Flickr by Bernard Spragg temperatures, protect from very harsh winter27 nights N. America M. liliiflora & M. denudata (Same native range Magnolia x spoelbergii for both species) Belgian Yellow Magnolia M. acuminata Complex Backcrossed Hybrid between three species, mainly M. acuminata

East Asia

‘Daphne’ Spring .

Magnoliaceae Magnolia Family

Small Tree

Photograph from The Garden Diary (CC) Charles H Williams 28 Magnolia stellata Star Magnolia

Japan

‘Centennial’ Spring . ‘Royal Star’

Magnoliaceae Magnolia Family

Small Tree

Photograph from Flickr (CC) Ting Chen 29 Mahonia aquifolium N. America Oregon Grape

‘Apollo’ Spring .

Berberidaceae Barberry Family

Medium Shrub

Photograph from Flickr (CC) Maja Dumat 30 Malus floribunda Japanese Crab Apple

Korea

Spring . - Species - Autumn (Fruits)

Rosaceae Rose Family

Small Tree

Photograph from Flickr (CC) Maja Dumat, Vanlap Hoàng (fruit) 31 Meconopsis betonicifolia Tibet Himalayan Blue Poppy Syn. M. baileyi

- Species - Summer . ‘Mop Head’

Papaveraceae Poppy Family

3ft Perennial

Photograph from Flickr (CC) Tim Waters 32 Meconopsis punicea Sichuan Red Poppy

China

‘Sichuan Silk’ Summer .

Papaveraceae Poppy Family

2ft Perennial

Photograph from Flickr (CC) Steve Garvie 33 Papaver cambricum Europe Welsh Poppy

None Mid Spring - Early Autumn

Papaveraceae Poppy Family

2ft Perennial

Photograph from Flickr (CC) Jill Catley 34 Pieris japonica Japanese Andromeda Bush

East Asia

‘Blush’ ‘Purity’ Spring . ‘Mountain Fire’

Ericaceae Heather Family

Small Shrub

Photograph from Flickr (CC) Pony Lauricella 35 Rheum palmatum Ornamental Rhubarb

East Asia

‘Bowles Crimson’ Summer . ‘Savill’

Polygonaceae Knotweed Family

6ft Large Perennial

Photograph from Flickr (CC) Mrs Enil 36 Rhododendron hippophaeoides Sichuan Blue Rhododendron

China

‘Haba Shan’ Spring .

Ericaceae Heather Family

Medium Shrub

Photograph from Flickr (CC) Plant Image Library 37 Rhododendron luteum Eurasia Yellow Azalea

- Species - Spring . (Possibly mildly invasive so AGM tentatively removed recently)

Ericaceae Heather Family

Large Shrub

Photograph from Wikipedia (CC) Chrumps 38 Rhododendron vaseyi Pinkshell Azalea

N. Carolina

- Species - Mid Spring - Early Summer

Ericaceae Heather Family

Medium Shrub

Photograph from Flickr (CC) Plant Image Library 39 Rhododendron yakushimanum Yakushima Rhododendron

Japan

‘Koichiro Wada’ Spring . ‘Hachmann's Polaris’

Ericaceae Heather Family

Medium Shrub

Photograph from Flickr (CC) A Qiáo 40 Ribes odoratum N. America Scented Golden Currant

None Spring .

Grossulariaceae Currant Family

Medium Shrub

Photograph © Thomas McBride 41 Ribes sanguineum N. America Red-flowered Currant

‘Koja’ Mid Spring - Early Summer ‘Pokey’s Pink’

Grossulariaceae Currant Family

Medium Shrub

Photograph from Flickr (CC) Andrew A Reding 42 Ribes uva-crispa Afro-Eurasia European Gooseberry

- Species - Mid Spring - Early Summer

Grossulariaceae Currant Family

Small Shrub

Photographs from Flickr (CC) Kev Wheeler (Fruit), Peter Stenzel (Flowers) 43 Rudbeckia fulgida N. America Orange Coneflower

var. deamii Late Summer - Mid Autumn ‘Goldsturm’

Asteraceae Daisy Family

2ft Perennial

Photograph from Wikipedia (CC) Jerzi Opiola 44 Sambucus nigra Eurasia Common Elder

f. laciniata Late Spring - Midsummer ‘Thundercloud’

Adoxaceae Moschatel Family

Small Tree

Photograph from Flickr (CC) Andreas Rockstein 45 Tropaeolum majus Peru Garden Nasturtium

F

‘Alaska series’ Midsummer - Early Autumn ‘Whirlybird series’

Tropaeolaceae Nasturtium Family

1ft Trailing Annual

* This plant will not survive below -5’c night temperatures Photograph from Flickr (CC) Mayank Sharma 46 Vaccinium corymbosum N. America Garden Blueberry

Late Spring . ‘Duke’ ‘Spartan’ Summer . (Berries)

Ericaceae Heather Family

Medium Shrub

Photograph from Flickr (CC) Maja Dumat (Flowers) & Rob Thurman (Fruit) 47 Vaccinium cylindraceum Macaronesia Azores Blueberry

- Species - Midsummer - Early Autumn

* Ericaceae Heather Family

Medium Shrub

* This plant will not survive below -10’c night Photograph from Wikipedia (CC) Christer T Johansson temperatures, protect from very harsh winter48 nights C. Asia Viburnum East Asia Viburnum x bodnantense farreri Bodnant Viburnum Viburnum farreri x Viburnum grandiflorum

Viburnum grandiflorum

‘Charles Lamont’ Mid Autumn - Early Spring ‘Dawn’ ‘Deben’

Adoxaceae Moschatel Family

Large Shrub

Photograph from Flickr (CC) Peter Stenzel 49 Viburnum opulus Eurasia Guelder-rose

‘Compactum’ ‘Rosea’ Late Spring - Midsummer ‘Xanthocarpum’

Adoxaceae Moschatel Family

Large Shrub

Photograph from Flickr (CC) Fred F 50