Carniverous Plants
Carnivorous plants seldom enter the consciousness of most gardeners. While many of us have kept – and possibly killed – a Venus flytrap at some point in our lives, that's where the novelty usually ends, which is a great pity because, armed with a little information, you'll soon discover that carnivorous plants are surprisingly easy to look after and are incredibly beautiful to look at. They are also a fun way to engage children in gardening - it may be the age of innocence, but children love the macabre! The idea of flesh-eating plants luring insects to their sticky end has instant gore appeal. In the process of keeping a small collection, children (and adults!) learn a great number of valuable gardening skills.
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If you decide to have a go at growing carnivorous plants, the most important thing you'll need is a steady supply of rainwater. Without a water butt you'll struggle to provide the right conditions - chlorinated tap water will eventually kill your plants. Some carnivorous plants, such as the Nepenthes pitcher plants, come from tropical countries, so need a heated greenhouse to survive. These are best left to specialist growers.
There are plenty of others, however, which are easy to grow. Pitcher plants (Sarracenia), with their long trumpets, are native to the US and many are hardy. Several sundews (Drosera) and butterworts (Pinguicula) are hardy, and both have species that occur in the UK. Slightly less hardy is the Californian cobra lily (Darlingtonia), which benefits from the shelter of an unheated greenhouse to over winter. Propagate your plants in the greenhouse in spring to summer, but then keep them there to catch whitefly and other greenhouse pests. And in your home, keep a sundew by the fruit-bowl to control fruit flies. |
Insect Trapping Plants
There are more than 300 species of carnivorous plants. The ones listed below are all easy to grow despite their exotic look, and can be kept in a cool greenhouse over winter. Trumpet pitcher or huntsman's horn (Sarracenia fraya) Classic yellow trumpets with red veining and extraordinary flowers. Insects drown in the liquid-filled traps. Sundew (Drosera) Tall, spindly leaves that are covered in fine hairs all the way up. The hairs are coated in a sticky mucus, from which insects can't unstick themselves. Venus flytrap (Dionaea muscipula) Readily available to buy as a houseplant, but grows better in a cool greenhouse, or outside in summer. Fine hairs on the inside of the traps trigger the snapping mechanism when touched by struggling insects. Butterwort (Pinguicula) Flat, pale leaves that resemble those of succulents, albeit for their sticky surface. Unlike most other carnivores, they prefer partial shade. Cobra Lily (Darlingtonra) Long trumpets that end in a cobra-shaped curved head with a checkered top. Insects find their way in but can't figure their way out very easily. |
Why Do Plants Catch Flies?
In habitats where nutrients are scarce, such as on very sandy soils or in acidic peat bogs, some plants have developed methods of extracting nutrients from animals instead.
Carnivorous plants lure or trap insects in different ways. Pitcher plants use sugary nectar to lure bugs into their liquid filled traps, while Venus flytraps snap shut when trigger hairs are touched. Butterworts emit an inviting smell, which stimulates flies to land on the sticky leaves, while the glistening leaves of sundews fold over, trapping their prey in a sticky embrace. Cobra lilies confuse their prey with their curved traps – once inside, there is no obvious way out. When growing carnivorous plants at home, it's important to replicate the conditions they are used to in the wild. This means providing a potting mixture that is poor in nutrients, and peat is the best choice. Ordinary compost mixes contain fertilisers, which can kill your carnivores, so don't be tempted by multipurpose. |
Look, Don't Touch !
Why is it that people find it impossible not to touch a Venus flytrap? It might be fun to see the traps snap shut, but this uses up a lot of energy for the plant without the reward of a tasty snack at the end! Repeated opening and closing without replacement nutrition can eventually kill the plant off.
Touching sticky carnivorous plants also causes them stress: more mucus is produced and energy is used to slowly curl the leaf. Similarly, if a plant looks like it's been overeating, don't try to empty traps. This can easily result in damage, which may lead to die back and a gradual weakening of the plant. |
Conservation of Carnivores
Many carnivorous plants are endangered in the wild, so by growing them at home, you are helping to conserve them. Peat use is discouraged for environmental reasons, but carnivorous plants need a nutrient-poor medium. As an alternative, try Moorland cold.
Plant Up Your Own Collection
Containers are the perfect way to give hardy carnivorous plants the particular growing conditions they need. Here I’m growing Sarracenia's and cobra lilies in an old ceramic sink, which will spend most of the day in full sun. I keep my sink on a table outside the window so that I can look at the plants closely. Some carnivorous plants will happily live outside all year round but, as a precaution, move them to a cool, frost-free greenhouse in winter, but don't give them any heat as this can kill them.
- Line your container with plastic or a folded bin bag. Any container at least 20 cm deep would be suitable to house your collection.
- Fill the container with peat and add handfuls of perlite and lime free sand. Loosely firm it into the container.
- Knock the plant from its pot and tease out the root to encourage them to spread out.
- Make a hole and put the plant in position, back filling with compost mix, then lightly firm in place.
- Add a selection of plants of different heights, then water thoroughly with rainwater.
Take Root Cuttings
It's surprisingly easy to make more sundew plants, by taking root cuttings, much as you would with oriental poppies. Do this between spring and June.
- Take the plant out of its pot and you will see a tangled web of roots - just cut a few out to use as cuttings.
- Make up a potting mix if the following parts: 6 parts peat, 2 parts perlite, 1 part lime free sand.
- Sieve the mix, then fill a seed tray that has drainage holes.
- Lightly firm the surface, then space out the pieces of root on top.
- Keep the tray out of direct sun in the greenhouse, and in a month or so, curly stems begin to appear.
- Move young plants into individual pots filled with the same mix as above.
Dividing Plants
Just because they look exotic, it doesn't mean that you have to handle them with kid gloves. Sarracenia’s are easily divided by hand and, in most cases, are as tough as old boots.
They are slow growing, so only divide when they have become congested. Divide in March or April before the new traps are active.
They are slow growing, so only divide when they have become congested. Divide in March or April before the new traps are active.
- Turn the pot upside down over a seed tray and hold the traps by the base.
- Carefully tease the root ball apart, then tear one half from the other.
- Place in a pot that is only a few centimetres larger. Use the compost mix mentioned previously for potting up.
- If you have a single trap left over, you can pot it up provided it has a few roots.