Choosing plants that don’t mind hot, dry spells of weather is a good idea in a changing climate. There are lots to choose from. Some of my favourite drought-tolerant plants are sedums because of the leaf colours. Alpine plants are also very hardy and naturally grow in dry places.
In this article, I want to show you how to make a rock garden to show off your alpine, succulent and other plants. Plus I’ll share with you some of the plants that I think are just perfect for rock gardens. First, though, think about where you might put your rock garden.
Choosing Where to Put Your Rock Garden
Some things to think about:
- Will plants get enough sun? Ideally, you want a very sunny spot – avoid overhanging trees, tree roots and shady areas. Your rock garden should have full sun for most of the day if possible.
- Avoid damp areas that don’t drain well. Your rock garden plants will not survive in this sort of soil. One way to improve drainage is to add grit to your rock garden soil – more on this later.
- If there are areas of your garden that are prone to frost in the winter, avoid these.
Once you’ve decided on the perfect spot, you’ll need a few materials.
Finding Materials for a Rock Garden
Using salvaged stone is a sustainable way to make a rock garden. Talk to a builders’ merchant, garden centre or landscaping service to get an idea of what’s available locally.
It’s also worth doing a search on the internet to see what you can get secondhand in your area – people sell stuff like this on auction sites. You may even find free materials on recycling sites.
As well as stones of different sizes you may need gravel, compost, topsoil, horticultural grit and sand, depending on the size of your project. Oh, and some muscles to move the stones around! If this all sounds a bit daunting, you could think about asking a landscape gardener to carry out the work for you.
Building Your Rock Garden: 10 Step Guide
When I’m doing a project in the garden, I like to sketch a little plan so I can see what goes where. It’s useful to do this to check you have thought about everything before you start.
Think about how the rock garden will look from different viewpoints. Consider what will work best for sun-loving plants. South-facing is best to get the most sun.
- Rubble/old bricks for a base layer
- Sand for marking out
- Polythene sheeting or grass turves
- Stones of different sizes – using the same type of stone throughout looks good
- Extra topsoil with added grit (30%)
- Compost with added grit (30%)
- Gravel to spread around plants
- Crowbar to help with manoeuvring large stones
- Mark out the area of your rock garden with a trail of sand. If you are removing grass, keep the turves as these will be useful later. Make sure the ground is totally free of weeds before you start adding materials to it.
- Make a base layer with rubble and old bricks to fill the footprint of your rock garden, about 15cm/6 inches deep.
- On top of this base layer, add the turves you saved earlier, grass side down. This stops the rubble mixing with the compost you will add. Or, if you don’t have turves, you could use polythene sheeting with holes punched every 10cm/4 inches or so for drainage.
- Place the large stones first. Make hollows for them to rest in. Try to get a natural look, with stones leaning slightly backwards and the lines in them running horizontally.
- Add smaller stones once you have the large ones placed and arrange until you are happy with the display.
- Set stones in place by adding your topsoil in and around them (a mix with 30% grit is ideal for drainage). The bottom third of all the stones should be buried.
- Leave the soil quite loose around the sides of the stones, don’t firm in too much. This is where your plants will go. Add your compost mix on top of the topsoil to create places with enough depth for planting.
- Water your rock garden plants while they are still in their pots. Place them in position so you can see if you have got them in the right places.
- When you are happy, plant them firmly in the compost.
- Add a layer of gravel around each plant – this keeps their leaves away from damp compost, holds moisture in the soil and adds an arid look to your rock garden.
What Types of Plants Do Well in a Rock Garden?
Perfect rock garden plants are those that naturally thrive in dry, rocky regions. These include alpine plants. Alpines grow high up on mountains in cold, dry places with lots of light. Succulents are also good choices. They often grow in much warmer conditions than alpines, but some will tolerate cold temperatures too. Like alpines, they love dry, sunny places.
As well as alpines and succulents, other plants look good in a rock garden. Some plants will enjoy the shade cast by a large rock, so don’t rule out shade-loving plants either.
If you are planning on having a rock garden as a permanent feature, you probably won’t want to move plants from it indoors in the winter. So choose plants that will survive cold weather.
This is important when you are buying succulents because some of them are tender plants. This means they won’t survive outdoors in freezing temperatures.
You’ll find my top fifteen plants for a rock garden below. This includes my pick of the best hardy succulents, alpines and other plants.
My Top 15 Plants for a Rock Garden
There are lots to choose from.I’ve only included plants that will be happy to spend the winter outdoors. My list also includes spring, summer, autumn and winter choices so you will get colour all year round. In alphabetical order then:
- Armeria maritima (sea pink or sea thrift) A compact evergreen cushion-like plant. Soft pink flowers emerge on long stems in summer. A coastal plant but it’s happy in all sorts of gardens and great in rock gardens. Deadhead flowers to keep the blooms coming.
- Crocus kotschyanus (Kotschy’s crocus) An autumn-flowering crocus with pale lilac flowers, this plant will add colour to your rock garden once the summer flowers are over.
- Cyclamen coum (Persian violet) This beautiful purple-flowered plant survives cold temperatures. It will brighten your rock garden in late winter or early spring.
- Gentiana acaulis (stemless gentian) With incredible bright blue flowers that stay close to the ground, this gentian is ideal for a rock garden. Flowers in spring and the leaves are evergreen.
- Hylotelephium cyaneum ‘Sakhalin’ (azure stonecrop) This is a mat-forming succulent with short dark red stems and grey-purple leaves. Purple-pink flowers appear in late summer and early autumn.
- Iberis sempervirens (candytuft) Pretty white flowers appear on evergreen foliage in spring. The flower stems stay relatively short, making this an ideal rock garden plant.
- Linaria alpina (alpine toadflax) Alpine toadflax is a trailing plant with pretty purple and orange flowers in summer, quite an unusual combination. The leaves are a blue-green colour.
- Phlox subulata (creeping phlox) This plant is an excellent choice for ground cover. It will spread very happily over a rock garden and has masses of pink flowers in spring and summer. Foliage is evergreen.
- Pulsatilla vulgaris (pasqueflower) The pasqueflower is a striking plant that appears around Easter. The furry, drooping purple flowers look great in a mass on the bank of a rockery. Prefers a chalky soil.
- Ramonda myconi (Pyrenean violet) This pretty violet is one to choose for the shadiest parts of your rock garden. It prefers full shade and will grow very happily in rock crevices. Flowers appear in spring and summer. Evergreen.
- Saxifraga (many different varieties) Saxifrages are winter hardy and produce pretty flowers on tall stems from evergreen rosettes of leaves. Some prefer part-shade and others like full shade. Perfect for the shady sides of rocks.
- Sedum dasyphyllum (Corsican stonecrop) An excellent groundcover plant which will thrive in hot, sunny conditions. Wonderful purple-blue leaves. A hardy succulent that doesn’t need to be indoors in winter.
- Sedum oreganum (Oregon stonecrop) A low-growing succulent that covers the ground well in hot, dry areas. The leaves turn an eye-catching shade of red. Star-shaped yellow flowers appear in summer.
- Sempervivums (many varieties) These succulents are easy to grow and will survive winter. There are many choices. Have a look for ‘Terracotta Baby’, ‘Bronco’, ‘Rita Jane’, ‘Pippin’, ‘Pluto’ and ‘Purple Dazzler’. Sempervivums like full sun and well-drained soil. Also known as houseleeks.
- Veronica prostrata (speedwell) Speedwell is a creeping plant which looks great in and around rocks, forming a dense mat. Tiny blue flowers with white centres appear from spring onwards.
I hope I’ve inspired you to make your own rock garden. And if you only have a small space, don’t worry! You can make a mini rock garden with alpines and succulents in a container.