Air and water are needed for plant roots to support healthy growth. Saturated soils will have insufficient oxygen for healthy root function and may lead to root decay. Fortunately, there are some shrubs and herbaceous

Perennials are plants that live for multiple years. They come in all shapes and sizes and fill our gardens with colourful flowers and ornamental foliage. Many are hardy and can survive outdoors all year round, while less hardy types need protection over winter. The term herbaceous perennial is used to describe long-lived plants without a permanent woody structure (they die back to ground level each autumn), distinguishing them from trees, shrubs and sub-shrubs.

For mixed extremes, see our list of plants tolerant of both wet and dry soils.

Preparation for planting

Before planting trees in wet conditions, you may need to improve drainage. On soils prone to wet conditions in winter and drought in summer, such as heavy clays, improve the soil by incorporating bulky organic matter. This should be done over as large an area as possible. Artificial drainage will be necessary if severe waterlogging or flooding is a problem.

Planting

Improve drainage at the base of the planting hole by forking through any compacted soil. Fork through the sides of the planting hole or break down the sides into the planting hole when backfilling. This avoids creating a planting 'bucket' or sump which fills with water: a problem that can lead to poor establishment or the death of the tree. On heavy soils prone to winter wet, protect the finer surface feeding roots by planting trees on a slightly raised mound to improve drainage around the root system and carry out the planting in early spring.

(*) suitable for acid soils
(e) evergreen
(^) tolerant of wet soils but better suited to moisture retentive well-drained soil
AGM - The RHS Award of Garden Merit

Where only a genus is mentioned, such as Spiraea, all species can be considered. Cultivars of the species listed, such as Hydrangea macrophylla ‘Altona’ are also suitable.

Trees

Acer griseum AGM, A. negundo, A. palmatum, A. pensylvanicum, A. rubrum
Aesculus pavia 'Atrosanguinea' AGM
Alnus cordata AGM, A. glutinosa: Native to GB and Ireland, A. incana 'Aurea', A.× spaethii 
Amelanchier including Amelanchier lamarckii AGM
Betula nigra (river birch), B. pendula:

A native plant is one that originated or arrived naturally in a particular place without human involvement. In the British Isles, native plants are those that were here during the last ice age or have arrived unaided since.

Gardeners often use the word variety when referring to a specific plant, but the correct botanical term is 'cultivar'. Whichever word you use, it means a distinctive plant or plants, given a specific cultivar name and usually bred to enhance certain characteristics, such as flower or fruit size, colour, flavour or fragrance, plant size, hardiness, disease resistance, etc. Additionally, it is worth knowing that, botanically, variety has another meaning - it refers to a naturally-occurring distinct plant that only has slight differences in its looks. For example, Malva alcea var. fastigiata differs from typical plants by having an upright habit.

Cultivar

A plant that is not native but was introduced to the UK, through human activity, before 1500 and is now naturalised. Well-known archaeophytes include cornflower, ground elder and fennel. RHS plant profiles classify archeophytes as native plants.

archeophyte

Conifers

Abies alba (silver fir), A. koreana AGM (Korean fir), Abies procera (noble fir) (*) (^)
Chamaecyparis lawsoniana, C. obtusa, C. pisifera (*) (^)
Ginkgo biloba AGM (^)
Metasequoia glyptostroboides (dawn redwood) AGM, M. glyptostroboides Goldrush = 'Golden Oji' AGM (^)
Picea abies, P. glauca, P. omorika AGM, P. orientalis AGM, P. pungens (*) (^)
Pinus sylvestris: Native to GB
Pseudotsuga menziesii AGM 
Sequoia sempervirens AGM
Taxodium distichum (swamp cypress) AGM (*)
Thuja occidentalis (white cedar), T. plicata (western red cedar) 
Thujopsis dolabrata (^)
Tsuga canadensis (Eastern hemlock), T. heterophylla AGM

Shrubs for acid soils (chalk haters)

Andromeda polifolia (*)(e): Native to GB and Ireland
Arctostaphylos uva-ursi 'Vancouver Jade' (*)(e): Native to GB and Ireland
Aronia arbutifolia 'Erecta' (*)
Clethra alnifolia (*)
Enkianthus campanulatus AGM (*)(e), E. cernuus f. rubens AGM (*)
Erica tetralix (*)(e): Native to GB and Ireland
Gaultheria procumbens AGM (*)(e), G. shallon (can be invasive) (*)(e)
Kalmia angustifolia AGM, K. polifolia (*)(e)
Ilex verticillata (*)
Lindera benzoin (*)
Myrica gale (*)
Rhododendron hippophaeoides (e)(*), R. viscosum (*)
Vaccinium myrtillus (bilberry) (*): Native to GB and Ireland, V. vitis-idaea (*), V. corymbosum (blueberry) (*)
Zenobia pulverulenta (*)

Evergreen shrubs

Berberis stenophylla AGM (e)
Magnolia grandiflora (e)
Phyllostachys (bamboo) (e)
Pseudosasa (bamboo) (e)
Sasa (bamboo) (e)

Deciduous shrubs

Calycanthus floridus, C. occidentalis
Cornus alba, C. florida, C. sericea
Diervilla × splendens
Hippophae rhamnoides: Native to GB and Ireland
Hydrangea macrophylla, H. paniculata
Kerria japonica 'Pleniflora' AGM
Leycesteria formosa
Neillia thibetica
Photinia villosa
Physocarpus opulifolius 'Diabolo'
Prunus spinosa (blackthorn): Native to GB and Ireland
Rubus arcticus
Salix repens
Sambucus nigra: Native to GB and Ireland
Sorbaria
Spiraea
Symphoricarpos
Viburnum opulus: Native to GB and Ireland
Weigela
Wisteria floribunda, W. sinensis

Herbaceous perennials

Acorus gramineus ‘Ogon’
Actaea
Astilbe
Caltha palustris: Native to GB and Ireland
Cardiocrinum cordatum var. glehnii, C. giganteum
Darmera peltata AGM
Dodecatheon meadia AGM, D. hendersonii AGM
Euphorbia griffithii, E. sikkimensis AGM
Filipendula ulmaria
Hesperantha coccinea 'Sunrise’ AGM
Hosta
Iris ensata ‘Rose Queen’ AGM, I. laevigata, I. pseudacorus: Native to GB and Ireland, I. sibirica ‘Tropic Night’ AGM
Ligularia przewalskii
Lilium pardalinum AGM, L. superbum
Lobelia cardinalis AGM
Lysimachia nummularia: Native to GB and Ireland, L. punctata
Lythrum salicaria
Mimulus luteus, M. primuloides, M. ringens
Monarda didyma
Primula denticulata AGM, P. japonica
Trollius
Zantedeschia aethiopica

Links

AGM Plants
RHS Find a Plant