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
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’.
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 like Trifolium rubens and Trifolium ochroleucon are star-performers on chalky soils. In fact, most plants in the legume family (Fabaceae) dislike acid soils.
Jacob’s ladder (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.
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.
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, 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.
Lilacs (syringa) grow best on chalky soils. Planted here, you’ll be rewarded with richly scented flowers and attractive, heart-shaped leaves.
Getting the best from alkaline soils
- Grow alkaline-loving plants
- Avoid lime-hating plants
- Mulch regularly
- Water plants well
- Feed plants regularly