Category Archives: Carnivorous Plants

Pitcher plant, Sundew, Venus Flytrap

Getting the Best Out of Your Venus Fly Trap

Venus Fly Trap

Dionaea muscipula

This is another must-have if you are thinking of starting a carnivorous plant collection.

The Venus Fly Trap is native to  the United States and is found in bogs and pine barrens.  As with all carnivorous plants it derives its energy from catching and digesting mainly insects.

The trapping mechanism has 3 hairs which are sensitive to touch and when triggered twice in succession will cause the trap to snap shut trapping its prey.  The reason why the trap will only respond after two triggers is so that the plant doesn’t waste valuable energy on non-prey items like a leaf blowing across the hairs.  Anything other than its intended prey causing the plants lobes to shut will greatly deplete the plants energy and is counterproductive so don’t be tempted to touch!  Once trapped the leaf will squash it’s prey between the two lobes, secrete its digestive enzymes and absorb all but the victims exoskeleton.

Only the exoskeleton remains …

Here you can see my plant has been busy and is waiting for the wind to tidy up after it.

Dionaea muscipula should be planted in a mix of vermiculite, peat and sphagnum moss and should be kept permanently moist either by regular overhead watering or by standing in a shallow tray of soft water (rainwater).  Never use tap water, there’s too much calcium in it and over time will kill the plant.  There’s much controversy regarding the use of peat in horticulture and I normally would not advocate its use as there are for most situations alternatives, but this group of plants will not tolerate anything but.

Levels of sunlight and how many hours a day the plant receives will affect its health.  As a rule it will generally need at least 4 hours of direct sunlight a day.  Couple this with fresh air (I open my kitchen window daily during the summer) and you are likely to get a low-growing rosette which is highly coloured.

New leaves forming …

Temperature also affects growth and in turn the watering regime.  The plant will tolerate temperatures just above freezing but growth will cease until the temperature rises again to 13 degrees centigrade.  Growth stops again above 27 degrees centigrade.  When there is no growth, watering should be reduced accordingly.

Dionaea muscipula can be propogated by seed, division or by leaf cuttings of the petiole.

As far as potential pests and diseases are concerned, the Venus Fly Trap may be susceptible to slugs (in the greenhouse, hopefully not indoors!) and botrytis.  Fresh air and regular tidying of dead and dying leaves will help to avoid this fungal disease.

Carnivorous plants in the home are a practical and eco-friendly solution to unwanted flying intruders and they are fun to watch too as they go about their daily business of catching flies and other insects.


Delicately Deadly

New flower spike on my Sundew forming, unfurling as we speak …

Drosera capensis

Pitcher Perfect

White Pitcher PlantI first became familiar with this beautiful plant as a trainee gardener at Down House in Kent (former home of Charles Darwin now owned and managed by English Heritage).

The white pitcher plant, Sarracenia leucophylla, belongs in the family Sarraceniaceae and is a master at catching its prey.  Within the family Sarraceniaceae there are 8 species of carnivorous herbaceous perennials.  S. Leucophylla is the one I have here at home.

In the wild they can be found in warm-temperate climates specifically along the south-eastern coastal plain of the United States.  Only one, S. purpurea can be found further north and into Canada.  All species require distinguishable summer and winter seasons and strong direct sunlight for optimum growth. The white pitcher plant produces two flushes of pitcher growth a year, one in spring and again in autumn.  They grow in environments which are permanently wet such as fens, swamps and grassland.  These habitats tend to be nutrient poor especially in nitrates, and highly acidic.  Nutrients become unavailable to the plant either due to leaching of water from the soil or the plants’ roots are unable to take up nutrients because of the low pH.  They compensate for this by catching their insect prey instead.

So how exactly do they go about this?  All Sarracenia traps are immobile and rely on a combination of lures and specialized morphological characteristics to attract and trap their prey.  These include narcotic nectar, colour, scent, waxy deposits which clog insects’ feet and inescapability due to the complex structure of the pitcher’s leaves.  Once the insect has fallen into the tube a series of inward pointing hairs make escape impossible.  At the very bottom of the pitcher the insect is drowned in a small pool of water which also contains digestive enzymes.  Usually every part of the insect is digested except the exoskeleton and over the course of the summer the pitcher will fill up with the remains.

Pitcher Plant

Waiting for the next meal …

Cultivation at home requires only a few important rules be followed:-

  • Plant in a mixture of sphagnum, sand and leafmould to ensure a low pH;
  • NEVER water from the tap, it will be too alkaline, always use rainwater;
  • Keep the substrate moist at all times by standing in a container that will collect run-off from regular watering and keep the roots moist by capillary action (but make sure that the water doesn’t stagnate);
  • Place in a bright spot with direct sunlight, they won’t thrive in shade;
  • No need to feed them but try and place them where there will be a source of insects;
  • Remove dead leaves from the base;
  • In a cool greenhouse they need a minimum night-time temperature of 4.5 degrees centigrade (40 degrees farenheit) and in winter a daytime minimum of 10 degrees centigrade (50 degrees farenheit).  Damping down in summer is recommended to keep the humidity high but spraying the leaves directly should be avoided.

Sadly, this species of Sarracenia is threatened in the wild by loss of habitat and the cut pitcher trade for floristry.  Other land management techniques are also contributing to their gradual decline including herbicidal run-off from agriculture, urban development and land drainage for forestry.

This one is quite safe though and languishes in luxury on my kitchen windowsill where it earns its keep by catching the unwary insect or two.

Fly’s Eye View …