Best plants for alkaline soils

BBC Gardeners' World Magazine

Published: Monday, 16 December 2019 at 1:59 pm

Check out some of the best plants to grow in lime-rich or chalky soils.

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Alkaline soils are those that have a high pH, usually as a result of being rich in chalk or limestone.

In the UK, these soils are often found on chalk downlands, including areas like the South Downs, Chiltern Hills and Salisbury Plain. If you live in an area with limestone deposits, your soil is also likely to be alkaline.

To be certain of your soil pH, test your soil pH with a kit from the garden centre, or online.

Ericaceous, lime-hating plants shouldn't be planted in alkaline soils, as they can't take up important nutrients like iron.

Discover the best plants for alkaline soils that you can grow, below.

Lily of the valley

Lily of the valley, Convallaria majalis

White bells of lily of the valley

If you're looking for a ground cover plant for alkaline soils, consider lily of the valley. The flowers are sweetly scented and there are several attractive cultivars to grow, including 'Albostriata' and 'Hardwick Hall'.

Phacelia

Phacelia flower

Mauve phacelia flowers

Though often grown for green manure, it's worth letting phacelia flower to witness its ability to attract numerous pollinators. It's part of the borage family Boraginaceae, which includes lots of other lime-loving plants like borage, viper's bugloss and anchusa.

Ornamental clovers

Trifolium ochroleucon

White ornamental clover flowers

Ornamental clovers like Trifolium rubens and Trifolium ochroleucon are star-performers on chalky soils. In fact, most plants in the legume family (Fabaceae) dislike acid soils.

Wild marjoram

Wild marjoram Origanum vulgare

Wild marjoram flowering pale pink

Wild marjoram, or oregano (Origanum vulgare) is easy to grow if given plenty of sun and well-drained soil. Cultivars to grow include 'Aureum' and 'Compactum'. A popular plant for butterflies.

Polemonium

Polemonium in flower

Blue polemonium flowers

Jacob's ladder plant (Polemonium caeruleum) is a pretty, native perennial that will relish a moist, lime-rich soil. If the soil is quite thin, improve before planting by incorporating lots of organic matter such as leaf mould and well-rotted manure.

Sesleria caerulea

Evergreen blue moor grass

This native, evergreen grass is commonly known as blue moor grass, owing to the glaucous uppersides of the foliage. Grow Sesleria caerulea in full sun and expect it to gradually spread.

Lavender

Lavandula angustifolia 'Purple Treasure'

Lavender 'Purple Treasure'

Lavender, as well as other aromatic plants like rosemary, thyme and artemisia, will enjoy the free-draining soil provided by chalky soils. Grow them in full sun to get the best from them.

Honeysuckle

Lonicera 'Serotina'

A honeysuckle bloom

Our native honeysuckle, Lonicera periclymenum, does well in a variety of settings, and there are plenty of cultivars to grow, including 'Graham Thomas' and 'Serotina'. Overgrown honeysuckle? Find out out to prune honeysuckle.

Spindle

Euonymus europaeus

Vivid pink-winged, orange fruit of the spindle tree

Spindle, Euonymus europaeus, is a native shrub or small tree. The autumn colour is spectacular and, when the leaves have fallen, brightly-coloured fruits remain to provide interest.