With the onset of autumn the Venus Flytrap will start the process of entering dormancy.
Think of dormancy as a rest or sleep where the growth of the plant will slow and eventually stop. For the long term health of the plant a period of dormancy is essential to reset biological processes and conserve stored energy in the bulb during the low temperatures, short days and lack of insects to feed on in the winter months.
Preparing your Venus flytrap for dormancy
Where the Venus Flytraps are kept in the environment of the average house, the temperature may be too high to enable dormancy to start, resulting in a plant that produces weak, straggly leaves and flowers during the winter months. This growth will be drawn and spindly due to the lack of light and will draw upon the stored energy in the bulb. To encourage dormancy it is now time to move your plant to its winter position (see below).
There may however be signs of dormancy starting. You will notice that the leaves that have been produced over the current growing season will start to die back as the chlorophyll in the leaf starts to break down. This will occur whether the trap has caught a fly or not.
Cutting off dead growth
The first sign of this change is a yellowing of the trap followed by the leaf stalk. Eventually the leaf will go completely black. At this stage a good pick over of the plant is important as this dead growth can provide a starting point for Botrytis (grey mould) to attack the plant.
Either pinch/pull off the old traps with fingers or use a small pair of scissors or tweezers. This is something that you will do periodically over the winter period as the traps die off. The pictures show the same plant at various stages of cutting back.
Plant ready to be cut back.
Plant after initial cut back – further die back will happen on the old trap and yellowing leaf stalks
but we will leave them to die back naturally.
Plant after further cut back. More leaves will have to be removed in a few months time.
With the slowing growth rate and dying back of the leaves, reduce the wetness of the compost by not leaving the plant standing in water for any length of time. Give just enough water for the pot to draw up and then leave the compost to dry out slowly but not totally before watering again. The best way to judge the water content of the compost is by weight.
DO NOT LET THE PLANT DRY OUT COMPLETELY.
Check for Pests
Check your plant for signs of insect pests especially aphids (greenfly) as the underside of the flat leaves that do remain provide the perfect place for these pests to spend the winter, draining energy and getting a head start in the spring. A spray of Provado (a systemic insecticide) should sort them out.
The perfect position is a cold greenhouse where temperatures can be allowed to go down well below freezing. During the winter of 09/10 our VFT?s went down to below -10?C in the greenhouse. You do not need to provide any winter heating.
If you do not have access to a greenhouse, an unheated or slightly frost protected conservatory is suitable (5?C or lower). Sun during the winter is not important as the plant will not be growing so even a north facing conservatory will do.
For growers who do not have the benefit of a greenhouse or conservatory you can over winter your plant outdoors in your garden. It is important to place your plant in a sheltered position out of cold winds. Some protection using a cloche of cold frame will help but is not essential. There are several areas in the country where the Venus Flytrap has been naturalised in the wild. It is important to put your plant outside before the onset of the very cold weather so it can acclimatise and become more frost hardy. If an exceptionally cold period if forecast, a covering of straw or fleece will help provide protection.
Those of you who have to keep their VFT indoors over winter should move your plant to the coldest room in the house to slow the rate of growth as far as possible. For a deeper dormancy* put the plant in the fridge for about 3 months, from December until the end of February. This can be done by cutting off all the growth above the ground and putting the just damp pot in a bag in the salad drawer, or by taking the plants out the pot, washing off all the compost and cutting off the traps and drenching in a suitable fungicide to prevent Botrytis before placing in a bag in the salad drawer. It sounds dramatic but it does work and is a method we have used in the past.
*ask permission from fridge owner first.
Not all Venus Flytraps die back to the same degree. Our observations show that the greener varieties tend to keep more of their traps over winter than the red ones. Do not expect all your flytraps to exhibit the same changes at the same rate and at the same time.
For many people getting their plant through the first dormancy will change their understanding of the Venus Flytrap enabling them to have success year after year.