A rock garden filled with the best rockery plants is a beautiful addition to a sunny outdoor space. Not only do they look great, but they're undemanding, too, as suitable plants tend to be drought-tolerant once established.
Rockeries complement a variety of garden trends, including Mediterranean garden schemes. And, as garden designer Melanie Hick points out, they can be as small or as large as you desire.
This makes them an ideal way to create a striking outdoor feature, whether you have a large bed or border to play with, a small courtyard, or even a balcony, she says.
There are many plants to choose from that will thrive in this sort of environment. So, to narrow down the list, we chatted with gardening experts to find out their top recommendations. Plus, you'll find a simple guide on how to build a rock garden, too.
8 of the best rockery plants to grow in your garden
Whether you're looking for fantastic colour, stunning succulents, or easy-care ground-cover, there's something for everyone in this mix.
1. Alchemilla alpina
Garden designer Harriet Worsley is, in her own words, "slightly obsessed with rockeries".
"Many of the plants that grow best there are alpines, which are often the plants we know and love – but miniature low-growing versions," she says. "Alpines are native plants from mountainous regions, which are often cold, dry, and windy and have little water."
Her favourite place for inspiration for rockery plants is the Royal Botanic Gardens, Kew – "they have incredible varieties in the rock garden and the alpine house. Not all are available in every garden centre, some are rare, but it’s fabulous to go to the gardens to get ideas," she says.
Harriet also likes to take ideas from nature when doing planting design. "I’ve found tiny alchemillas growing wild when walking up in the Pyrenees mountains in France. Alchemilla mollis is a favourite summer garden plant of mine, so you could try the tiny alpine version in your rockery, Alchemilla alpina, with its silvery-edged leaves and tiny sprays of acid green flowers."
This alluring plant tends to be resilient against pests and diseases and, as a perennial, will come back year after year. Like with all of the best rockery plants, ensure the soil is well-draining.
2. Sea holly
Emma Fell of Hillier Garden Centres recommends eryngium, also known as sea holly, as a captivating addition to rockeries.
With spiky, metallic-blue flowers and a thistle-like appearance, these drought-resistant plants prefer well-drained growing conditions so thrive in sandy, coastal areas, she says. "This unique plant adds texture and visual interest to outdoor spaces and evokes the wild beauty of the coastline." These are also popular plants for pollinators.
As well as the classic blue varieties, such as Eryngium x zabelii "Big Blue" available from Crocus, sea hollies can also be silvery in colour – Eryngium giganteum "Silver Ghost", also from Crocus, for example.
3. Helianthemum
Emma also recommends helianthemum due to its low-growing, spreading habit, which helps to cover ground quickly and fill gaps between rocks. "Additionally, its bright, vibrant flowers and drought-tolerant nature make it a perfect choice for adding colour and resilience to rocky landscapes," she says.
Annelise Brilli of Suttons agrees that these make some of the best rockery plants, noting that they're easy to grow and flower in profusion for weeks. "They require little attention other than a light trim back after flowering, which will often promote a second flush of blooms," she says.
Annelise highlights their versatile range of colours, too. These include soft pastels such as "Peachy Keen" to the sizzling orange of "Fire Dragon" (available from Suttons).
We also like "The Bride" helianthemum from Crocus for simple, white blooms with yellow centres – the perfect accompaniment to the quiet luxury garden trend.
4. Corsican mint
Pim Dickson of Mr Fothergill’s Seeds Limited recommends Mentha requienii, also known as Corsican mint, which he says is more unusual but well worth seeking out.
"An aromatic hardy perennial, it will come back quickly after dying down for winter. I love the way it flows perfectly over any contour wherever the mood takes it, to create a beautiful baize-like carpet just 1-2cm high. It attracts more comments than almost any other plant in my garden."
It's easy to grow and vigorous, Pim continues. If you’re worried about it spreading, he suggests growing it in a container sunk into a suitable space among the rocks. Be sure to give it an occasional water if it’s growing in full midday sun, he adds.
Corsican mint is available to buy from Crocus. As well as in a rockery, you could grow it as a patio container plant.
5. Erigeron karvinskianus
Harriet says, "One easy rockery plant to try is Erigeron karvinskianus which is a little frothy pink and white daisy.
"It’ll seed everywhere like crazy and grows in cracks and corners. Once it’s in your garden you’ll never get rid of it, but it’s the prettiest little plant – and it flowers and flowers and flowers."
Erigeron karvinskianus "Profusion" seeds are available to buy from Sarah Raven. We think they make a beautiful addition to a sunny rockery in a cottage garden scheme, or spilling over stone walls.
6. Thyme
Josh Novell, plant expert and director of Polhill, recommends thyme as one of the best rockery plants. "You need to plant thyme in a sunny location where it will receive at least six to eight hours of sunlight each day," he says. "You also need to ensure the soil is well-drained and on the sandy side, as thyme doesn't like waterlogged conditions."
According to Harriet, a good variety to try is the low-creeping Thymus serpyllum. "It should form a dense, beautiful mat."
Pim also recommends Thymus serphyllum, as well as Thymus pulegioides. Both, he says, are heat- and drought-tolerant, flower for ages, and remain evergreen for continued interest throughout the winter. "They are a favourite for me also because of their delicious aroma," he adds. "Planting them at the rockery edge, in and along paths where they tolerate occasionally being crushed by passing feet, adds an extra sensory dimension."
Thyme flowers are also excellent for bees, so these plants are a good pick if you're looking to rewild your garden. Try "Snowdrift" from Crocus for a carpet of white summer blooms.
Top tip: Josh says it’s important to regularly trim thyme to keep it bushy and prevent it from becoming woody.
7. Lewisia
"For a showstopping display, plump for Lewisia cotyledon," says Annelise. "Lewisias are spectacular in bloom, with sprays of starry, tropical-looking flowers held on long stalks above a neat rosette of succulent leaves.
"Although very hardy, they hate winter wet, so planting them on a vertical face is advisable," she says, adding that a crevice on the north or east side of a dry stone wall is perfect.
Try Lewisia cotyledon "Elise Mixed" plants from Suttons for an attractive range of hues.
8. Sedum
Josh says sedums are drought-tolerant and can thrive in poor soil, making them perfect for the well-drained conditions of a rockery. These succulent plants also come in various shapes, sizes, and colours, he adds.
"It’s best to plant sedums in a sunny spot," Josh continues. "This should enhance their colour and promote healthy growth, but it’s also crucial that you ensure the soil is well-drained. If your soil is heavy, consider adding grit or sand to improve the drainage."
When you go to water your plants, note that you only need to water sedums sparingly, as Josh points out – too much moisture can cause root rot.
For yellow flowers and variegated foliage, try Sedum takesimense "Atlantis", available from Thompson & Morgan.
Pim recommends sedum acre, commonly called biting stonecrop – a "great evergreen rockery plant that persists through winter and seems almost indestructible." He highlights how its small, succulent leaves provide an attractive contrast to other plants. "It fills the gaps between rocks beautifully, making the separate stones seem part of a single, natural entity," he adds.
Pim also suggests Sedum spathulifolium "Purpureum" and "Cape Blanco". "I’d go as far as saying that sedums like these are essential rockery plants."
FAQs
What are some other good succulents to grow in a rock garden?
Alongside sedums, Emma recommends sempervivums and delospermums as excellent choices for rockeries, due to their drought-tolerant nature and distinctive appearance. "Their fleshy leaves, unique shapes and variety of sizes add texture and can be a really unusual feature."
How do you make a rockery?
Garden designer Melanie says creating a rockery is rather simple. "First, select a sunny spot and prepare the land by removing any weeds," she says. Then, you'll need to gather your rocks of varying sizes, your chosen plants, and some small stones or gravel. Sourcing rocks from a local reclamation yard is a great option for a more sustainable garden, Melanie highlights. Emma also says rockeries are a fantastic way to use up any spare rocks, tiles or slabs that may be lying around.
“Next, map out the main structure either by putting pen to paper or by physically placing your rocks," Melanie continues. "Position larger pieces toward the back of the space and use smaller pieces to surround the arrangement and fill in any gaps between the bigger rocks.
“When you’re happy with the overall shape of the structure and desired positioning of each piece, it’s time to secure them in place. Make sure the large rocks, or 'keystones', are planted with a third of their depth into the earth, and use soil and smaller stones or gravel to firm them in."
When you're ready to plant, Melanie says to use compost to fill in the gaps between the rocks, then add your selection of plants. "Achieve a naturalistic look by positioning them in cracks and crevices where you’d expect to see plants popping up in their natural environment." To finish, she advises topping the compost with gravel or small stones.
Looking for more gardening tips, or perhaps some budget garden ideas to complement a rockery? Our guides have you covered.
