Optimal Greenery for High-pH Soils
In alkaline territories, where soil pH levels often exceed 7, growing the right plants can make all the difference. If you find yourself dwelling upon chalky landscapes like the South Downs or Salisbury Plain in the UK, or regions rich with limestone, then you've got yourself a prime spot for alkaline soils!
Laurence the gardener has got you covered with a rundown of the finest picks for those territory-taming, soil-loving plants:
- Lily of the valley – Smell the sweet nectar while adorning your alkaline soil with this ground cover gem. Pick from the irresistible scented cultivars like 'Albostriata' and 'Hardwick Hall'.
- Phacelia – Known as a green manure hero, but let it bloom to create a buzzing hub of pollinators on your alkaline patch. This borage family member joins fellow borage brethren like the stunning 'Viper's Bugloss' or the easy-to-love 'Anchusa'.
- Ornamental Clovers – The fabulous duo of Trifolium rubens and Trifolium ochroleucon will shine bright on your chalky soil. Most legume family (Fabaceae) members tend to be more comfortable in alkaline conditions, making them a stellar choice.
- Wild marjoram, or oregano (Origanum vulgare) – With a taste for the sun and well-drained soil, this aromatic delight will grow like a champ in your alkaline garden. Grab the "Aureum" or "Compactum" cultivars for an extra boost.
- Polemonium – A native British perennial that adores moist, lime-rich soil. Moisten the earth, add lots of organic matter such as leaf mould and well-rotted manure for the best results.
- Sesleria caerulea – You can't go wrong with this native, evergreen grass that glows under the sun on alkaline soil. Watch it gradually spread.
- Lavender – Aromatic plants like lavender, along with herbs like rosemary, thyme, and artemisia, just love the free-draining beauty of alkaline soil. Give them plenty of sun, and they'll flourish.
- Honeysuckle – Our native honeysuckle, Lonicera periclymenum, is versatile and grower-friendly. There's a wealth of cultivars to choose from, like 'Graham Thomas' or "Serotina". Overgrown? Check out our guidance on pruning honeysuckle.
- Spindle – A native shrub or small tree, the Euonymus europaeus is perfect for alkaline soils. As the leaves tumble autumn leaves, the colorful fruits provide a lively display.
- Lilacs – Savor the rich scent of lilacs (syringa) as they stretch their limbs across your chalky paradise. Plant these beauties for heart-shaped leaves and intoxicating fragrance.
Now, how do you get the best results from your alkaline soil? Glad you asked:
- Grow alkaline-loving plants – Research and select plants that thrive in high pH conditions.
- Avoid lime-hating plants – Don't attempt to force grow plants that are itching for acidic soil, like Acers, Rhododendrons, or Gardenias, in an environment that favors the high pH.
- Mulch regularly – Keep the soil barrier tight to prevent water evaporation and nutrient leaching.
- Water plants well – Make sure to water your plants thoroughly and not just the leaves, especially during dry spells.
- Feed plants regularly – Alkaline soil can be a challenge for some nutrient-starved plants; ensure they get frequent feedings to stay healthy.
Expert tip: If you need to alter the pH level of your soil, consider these techniques:
- Add an alkaline amendment such as hydrated lime or baking soda dissolved in water to further raise the pH or maintain it.
- If you long to cultivate acid-loving plants in pots, create a more acidic environment by using soil rich in peat or another organic matter. This method can work wonders if pursuing the Himalayan beauty of an Acer palmatum or the tropical allure of a Gardenia.
- Venture into the realm of home-and-garden enthusiasts and discover how Laurence the gardener recommends incorporating several plants suited to alkaline soils, such as lily of the valley, Phacelia, ornamental clovers, wild marjoram, Polemonium, sesleria caerulea, lavender, honeysuckle, spindle, lilacs, and euonymus europaeus, to create a stunning alkaline garden.
- To establish and maintain a thriving alkaline garden, follow these tips: grow alkaline-loving plants, avoid lime-hating plants, mulch regularly, water plants well and frequently, and feed plants regularly to compensate for potential nutrient deficiencies. In addition, adjust the pH level of your soil as needed using alkaline amendments like hydrated lime or creating a more acidic environment in pots using soil rich in peat or organic matter.
