Tabletop Mountain: make a mini alpine planter
by Rhiannon James
With their delicate foliage and tiny, jewel-like flowers, alpines are proof that small is beautiful. They’re also a great choice for city gardens because they grow happily in containers, need hardly any maintenance and don’t require much watering once they’re established. You’ll usually find them planted up in stone troughs or old sinks but for something a little different, why not try a tabletop planter. Not only will you get a close-up view of all the lovely details of these miniature mountain plants, you’ll also have an eye-catching centrepiece for your table all year round.
Stuff to get
- A container with at least one drainage hole
- Some small pieces of rock – preferably tufa
- Compost – John Innes Number 2 or 3 or a non-peat alternative
- Horticultural alpine grit
- Horticultural sand
- An offcut of turf
- Pieces of broken clay pot
- Washed pea gravel
- A selection of alpine plants
Tools you’ll need
- A spade
- A watering can
When to do it
Step 1: Make sure you’ve got a good spot
Alpines get lots of light in their natural habitat, high up on mountains, so it’s important to find an open and sunny spot for your container where the plants will be in shadow for no more than about one to three hours a day. If your garden does not get this much light, look for plants which are shade-tolerant. It’s also best to avoid places where there are overhanging trees or shrubs because alpines do not like drips.
Step 2: Choose a container
Stone is the traditional choice for alpine planters, but as it’s both expensive and impractically heavy, go for a lighter-weight alternative such as plastic, frost-proof terracotta or other ceramic, or one of the combination materials such as polystone. Plastic has a slight advantage over terracotta because it doesn’t dry out as quickly.
You’ll also need to work out what size of planter will fit your table best. If you’re planning on moving your container when the table’s in use you can go for something bigger, if you want to use it as a centrepiece, a smaller option will work better. Remember that you’ll also have to think about the final weight of the planter, especially if your table’s not that robust. We used a 40cm-diameter (and 20cm-deep) ceramic bowl. Whatever planter you choose, make sure it has at least one drainage hole and if it has been used before, give it a thorough clean before you start.
Step 3: Get some rocks
The roots of alpines like to grow in the cool, moist soil under rocks. You can recreate these conditions and add extra interest, by including a few small pieces of rock in your container. Tufa, a type of limestone, is the best option and because it’s soft and porous, you can easily bore holes to grow plants such as Saxifrages in. Tufa can be hard to track down though, so you could also try an alternative such as slate or schist. Choose rugged shapes and don’t be afraid of going for one large rock (in proportion to your container), with three or five smaller pieces positioned around it to create crevices for the plants.
Step 4: Choose your plants
Now comes the best part! There’s a huge number of alpines to choose from, but try to pick a selection of plants with a range of flowering periods and leaf forms for a long-lasting and varied display. It’s also good to pick plants with different habits for different spots in your container. You’ll need some to trail over the edges of your planter, some to grow in the crevices between the rocks, a few to create a carpet if you’ve got some flatter areas, and possibly one upright. Choose small, slow growing plants so that no one plant takes over and overwhelms the others.
Also, try to avoid being tempted to plant a small conifer or shrub. It’s more rewarding to stick to flowering alpines with interesting foliage, and the size of these plants will be a better fit for the container.
For the edges
Delosperma sutherlandii ‘Peach Star’ – this Delosperma is mat-forming with glossy succulent leaves that will trail over the edge. It also has very pretty, daisy-like flowers in summer.
Erodium x variabile ‘Roseum’ – during the summer, this Erodium produces lots of pink flowers with a delicate pattern of dark red veins.
Phlox douglasii ‘Crackerjack’ – from a mat of dark green leaves, a host of star-shaped magenta flowers appear in late spring and throughout the summer.
For the crevices
Saxifraga ‘Cloth of Gold’ – this Saxifrage forms a compact mound of bright golden foliage and in spring, small white flowers appear.
Sempervivum arachnoideum – this prehistoric-looking plant forms a mat of rosettes of deep red/ bronze succulent leaves with green bases and tips. Each one has a covering of hairs which looks like a spider’s web.
Lewisia ‘George Henley’ – sprays of deep pink flowers emerge from a cushion of dark green leaves from late spring until late summer.
Sedum spathulifolium ‘Cape Blanco’ – forming low mounds of creamy grey, fleshy foliage, this plant produces dense clusters of vivid yellow flowers through the summer.
For a carpet
Gypsophila cerastioides – this small mat-forming perennial has white flowers lined with purple stripes from late spring to early summer.
Dianthus x arvernensis – producing large numbers of bright pink flowers on long stems all summer, this Dianthus looks like a miniature firework going off.
Gentiana verna – in spring, this Gentian has star-shaped flowers of brilliant blue with bright white stigmas at the centre of each flower.
If you feel a little overwhelmed by all the choice, there are nurseries which will put together a selection for you. Hartside Nursery Garden in Cumbria (www.plantswithaltitude.co.uk), for example, offer a collection of ten plants for a trough, or you could ask for a smaller selection to fit your container. They will make up the collection using the best plants they have at the time of ordering.
Step 5: Set up your container
Setting up an alpine container is straightforward; you just need to follow a few simple steps:
1) Start by placing a few pieces of broken clay pot over the drainage hole(s), as this stops the movement of soil and allows free drainage which is vital for alpine plants
2) Then cover the rest of the base with broken pots, if you can get them, or coarse washed gravel, filling up the container until it’s a quarter to a third full.
3) Next, place a piece of turf upside down on top of the broken pot or gravel. This stops the fine soil filtering down into the drainage. To make sure your piece of turf is the right size for your pot, use newspaper to make a template which you can then cut around with your spade.
4) Then add your compost. John Innes Number 2 or 3 potting compost, or a non-peat alternative will be fine. You can add sharp grit and horticultural sand to the compost to further increase drainage. Firm the compost down gently as you add each layer, to stop it sinking later, and keep adding more until the container is full.
Step 6: Add the rocks
Try the rock pieces in a few different positions until you find the arrangement that works best. Each rock should then be well bedded into the soil with the base fully covered. Firm around all the edges of each rock before you start planting.
Step 7: Add the plants
As with the rocks, rearrange your plants while they’re still in their pots until you are satisfied with the look. Remember to bear in mind each plant’s needs and also whether it was chosen to go at the edge of the pot, between the rocks or in a flatter area. Start planting at the centre and work your way outwards to the edges of the container. Try not to plant the alpines so that the compost comes right up to their crowns. Instead, leave some space to tuck the decorative gravel under the cushion of each plant, which will keep the crown dry and prevent rot.
Step 8: Add the finishing touches
The final stage is to cover all the bare soil with washed pea gravel. This gives a more natural look to your container, helps to conserve moisture and stops the soil surface hardening up. Also, it stops soil being splashed on to the plants and spoiling their look when it rains or you water the container. Approximately 1-2cm should do the job. Tuck the washed pea gravel under the cushion of each plant so none of the foliage is in contact with the soil.
Step 9: Water the container
You should also water the plants during severe dry weather or if any appear to be wilting, particularly during the first year.
Step 10: Keep your plants happy
Your alpine planter will need little maintenance and should be fairly trouble-free. However, it’s good to periodically check the plants and to tidy them up as required, removing any dead flowers. In future years, you can also trim plants that are getting too large after flowering.
If you want to find out more, the Alpine Garden Society has a wealth of advice and information (www.alpinegardensociety.org ).