Popularised in the late 19th Century, terrariums are making a bit of a comeback – and rightly so! Although they have often been regarded as rather unfashionable over the intervening years, an increasing number of people are now rediscovering what they have to offer and there’s no doubting their ability to provide maximum impact in a very small space. If the idea of creating your own living landscape in miniature appeals, then as those old Victorian gardeners knew, they’re hard to beat.
There are many different designs of terrarium commercially available, with some of the most attractive modern ones echoing the hexagonal or octagonal shapes of the originals, but if you’re looking for something less formal, you can make a great display in almost any suitable container. A disused aquarium tank, a large jar or even a big glass bowl can all make the ideal beginnings for your bottle garden – so you can let your imagination run as wild as you like when it comes to finding something which will fit into the rest of your living space.
Of course, there are some limits. Whatever you pick has to be able to be thoroughly cleaned before planting; a terrarium is a largely self-contained world, so there’s no point in starting it off with a ready-made collection of bugs, pests and diseases just waiting to ruin your plants. Secondly, however attractive that bottle looks, do make sure that the opening is large enough for access. Once you’ve planted your garden, you’ll still need to do a spot of maintenance from time to time – so don’t make things hard for yourself by choosing something impractical.
The closed nature of the terrarium or bottle garden makes a few demands on planting too. It’s essential to make sure that the compost remains properly drained and doesn’t go sour, since it would be a major undertaking to try to solve this kind of problem once everything has become well established. A good drainage layer is a must, so start off with a generous layer of clay, gravel or pebbles – up to about 2 inches (5cm) – at the bottom and add a few pieces of horticultural charcoal to absorb any unwanted gases produced and help keep things fresh. The growing medium itself needs to be fairly light, but moisture-retentive, so a good quality potting compost, possibly with a little extra peat or peat-substitute added in, makes a good general purpose choice for this kind of growing.
Having settled on the plants that you want to use, it’s well worth spending the time on planning the actual planting regime carefully; altering it later will be difficult, so it pays to think it through at the start. Probably the most important thing to consider is whether your display will be viewed from the front, or needs to be equally attractive from all sides, principally because this affects the placement of taller and shorter plants. As a general rule, keep anything that is going to be relatively tall to the back or centre and plant lower growing species in front and you won’t go far wrong. It’s a simple and obvious point, but one that’s all too easy to forget, especially when you’re first setting it up with a lot of plants that all look about as big as each other.
Once everything is carefully in place, dress the surface between plants with a layer of moss, pebbles or small bark chips to help with water retention.
The Victorian terrariums were mainly popular for growing ferns and they’re still a perfect choice today, though virtually any fairly slow growing variety of plant that likes a fairly humid micro-climate can be grown in this way, so you needn’t feel too restricted for choice. It’s probably best to avoid anything which flowers, since dead-heading in the confines of a bottle garden can prove something of a challenge and any fallen blooms that do remain will rot, which is both unsightly and likely to affect the growing conditions inside.
Fortunately there are plenty of suitable candidates available with more than enough contrast in leaf shape and colour to make an eye-catching display anywhere. Some of the best candidates include:
- Asparagus Fern Asparagus densiflorus (Sprengeri) – not a true fern, but a striking taller plant which makes an ideal centre to the display.
- Stromanthe amabilis – a long established favourite with its broad fleshy striped leaves
- Creeping fig Ficus pumila (variegata) – a beautiful evergreen with variegated leaves
- Gold Clubmoss Selaginella kraussiana (aurea) – a striking plant, native to the Canary Islands
- Creeping moss Selaginella martensii – another dense and compact plant.
Bottle gardens and terrariums aren’t for everyone and they’re certainly not the easiest way to garden, but if the idea does appeal, it’s well worth giving them a try. Whether you want to grow something with particular needs that you can’t accommodate elsewhere, add a bit of interest to a room, or you’re simply a keen gardener who’s a bit short on space, these greenhouses in miniature might just be the thing for you.