I 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.
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.