Venus flytraps (Dionaea muscipula) 

Many VFTs die for their new owners after a few months, after getting progressively smaller and withering away. But they can live forever, and hopefully you will be able to keep yours large, healthy and multiplying until you have so many that you have to give some away.

 

Aside from the amount of red colour and trap size, variation is mostly in the teeth, with tiny “Microdent” teeth, and triangular “Dentate” teeth. These plants are typically slower growing or smaller than the typical types.

 

Triggering: What we all want to do when we get a VFT is to set off the traps. Not the best for the plants, but they can open and close a few times each. There are 3-4 hairs per lobe. Touch them twice to close. However it needs extra movement of the hairs to close fully, and to produce digestive enzymes for full digestion – so it is best for the insect to be alive and struggling. Dead insects fed to the plants can rot the trap due to not enough digestive enzymes, but the trap often dies after eating a big meal anyway, and will be replaced with new traps.

 

Habitat: It helps to know where a plant comes from to work out how to grow them. They grow in America on the border between North and South Carolina, which is 34°N. Similar latitude to Northland. They get steamy summers, but due to the ocean currents, the winter gets quite cold and it can snow there. They live in grassy swamps that need to be cleared of taller vegetation by regular scrub fires, and can grow well under power lines where vegetation is kept short by mowing, but the land is not otherwise disturbed.

 

When growing inside: VFTs love sunlight, and if grown on a windowsill need a Northerly window where the sun shines directly on the plant for at least a few hours per day. Sit in a tray of water so that the potting mix is always wet. However the roots don’t grow below the water level so deep pots grow longer roots and produce larger plants.

 

They go dormant in winter and need this dormancy for a big flush of growth in spring. In winter indoors, it is better to keep them in an unheated room where the growth will slow down and then they don’t need much light. In a heated room they will try to grow but winter sunlight isn’t enough to keep them healthy, and if they do survive in a weakened state, it reduces their spring growth.

 

It is best to grow the plants in trays of water (mark the minimum and maximum on the tray), but the salts naturally present in water can build up in a water tray as it evaporates and gets refilled. It becomes toxic to the VFTs so clean out the tray and flush the pot whenever you collect some rainwater, or leave it outside through winter so the rain can flush out the salts. Take care where you put the plants as birds can peck out the plants.

 

If the VFT is grown in a hot room such as a conservatory, or near an open window where wind can blow across the plant, then the humidity can be too low to just grow the plant in a tray. The hotter the temperature, the higher humidity is needed for large happy traps. Leaves can dry out, and new leaves and traps may be smaller. In this case, a terrarium or plastic tub with sides higher than the plant will keep the humidity around the plant.   

 

Remember: Lots of water, and lots of sunlight.

 

If you grow them outside: VFTs appreciate the sun and grow happily outdoors in a tray of water, but dry wind can shrivel the traps, slugs and snails damage the unopened traps, and birds can peck out the plants. The plants also start growing later in spring as they wait for frosts to finish. A bit of shelter on a porch or under the eaves is a good place and will protect them from strong wind, especially dry wind, but also hail. They can handle -5°C frosts in winter no problem at all, and I haven’t seen any Spring frost damage on new growth.

 

I recommend growing them in a glasshouse for maximum trap size and to stop damage from the elements. Excellent ventilation is needed to reduce heat in summer, and also in winter as the plants can go mouldy. They are dormant in Winter don’t need warmth then. A hothouse really gets plants growing faster in spring, and you can start your vegetable seedlings in there as well. Install a spray system for humidity so the plants grow beautifully at higher temperatures if it gets to the upper 30s instead of wilting or shrivelling if humidity drops. Watering by spray system is also good as you can grow plants without trays as that avoids salt build-up, and the potting mix is more aerobic without trays of water, which encourages longer roots and bigger plants.

 

Full sun in spring gives the fastest initial growth and largest traps, but I think that shade cloth is best on a hothouse in summer as you control the light to give the nicest colouration. The plants get a bit sunburnt in full summer sun, and look nicer with a bit of shade-cloth, but are still healthy.

 

Pots and potting mix: Best to repot every 2 years or whenever the trap size decreases or if the pot becomes full of plants.

 

VFT potting mix is peat moss or sphagnum moss mixed with fine pumice or coarse sand in equal amounts. DO NOT use commercial potting mix, as the fertiliser makes the traps tiny because they don’t need any more nutrients, and the petioles huge. The plants also lose their red colour and become prone to rotting and aphids.

 

You can transfer the existing potted plant directly to a bigger pot at any time if you don't disturb the roots. They only have a few roots which grow straight down so it is possible to transfer with minimum disturbance if you are careful.

 

To repot and divide the plant, tip the plant out of the pot and split the potting mix, then lift out the corm and roots. Division of the corm should be done in late Winter with the first signs of growth, but will survive transfer later in the season though it may stop growing for a while. If there is any damage to the corm then a new growing point needs to develop, and the initial leaves can be quite small. Make a hole in a new pot with a stick or plant tag, and pop the plant into this and firm the soil around it. This can stress the plant if there is any root damage and the plant will probably produce a few smaller traps.

 

Oderings and Mitre10 have peat and pumice to repot once your plant gets bigger, or if you want to create a mini-bog in a tub. You can place the pots directly in the planter box and just decorate with sphagnum moss, or else fill it up with the mix of equal amounts of peat:pumice and transfer the plants into it. A watering tube sunk into the mix is useful to see how wet it is.

 

Other methods of propagation

Plants can be grown from leaf and flower stalk cuttings if you lay them on the surface with a thin layer of sphagnum moss. I recommend cutting off the flower stalks anyway, as traps stop growing while the stalk is developing. Need to keep the temperature and humidity just right for this to work and the small shoots can take some time to get to a decent size. Can also try the water floating method where you put a leaf in a jar of water until shoots develop.

 

Seeds can be bought from overseas CP nurseries or on Ebay without any import issues, but a lot of other CPs cannot be imported and will be confiscated. You may see blue VFT seeds being advertised, but they don’t exist. I’d suggest that seedlings be grown indoors under LED growlights through the first winter so they reach maturity in two years instead of three. A lot of the seedlings die for me even, except when I grow them in tissue culture. Moss or algae out competes them or they can dry out easily. About half of them grow small traps, even from large parents, half are OK plants, and maybe 3 per hundred grow bigger traps than the parents. But that is the fun of breeding.

 

Problems:

Triggering traps cause them to die sooner and go black. Without food, the replacement leaves take a bit longer to replace. The plants don’t actually need to be fed so long as they are placed in a sunny spot with water and not triggered all the time.

 

If the potting mix gets too dry, even briefly, or the humidity is low because it gets a breeze or a draught, then the traps go black and the replacement leaves get progressively smaller until the plant stops growing leaves. VFTs can handle high temperatures so long as humidity increases with temperature from a spray system or in a tub with high sides that keep humidity around the plant.

 

I mentioned earlier that the insect needs to be wriggling or the trap may not close fully. Dead insects are more likely to rot and kill the trap. But in good conditions a new trap grows every week or two so don’t be too concerned if traps rot after feeding. Pull off black traps, and wait for the rest of the petiole to go black before removing it.

 

A bit of red colour in the trap is a good indication that it has enough light. One of my varieties is a lot redder than others, so the amount of red can vary but entirely green traps means that it does not get enough light. And then the petioles get a lot bigger to catch the sunlight and the traps become smaller. Using potting mix with fertiliser produces similar large petioles and small traps – and then dies.

 

Once you have got your plant growing beautifully, with lots of water and sunlight, after a few years it may decline in vigour. Salts from the water can build up, or else the potting mix can go stinky, or it might be so crowded with plants that they don’t have space. Best to repot the plant every two years, and if it is happy, it will fill the pot and need dividing by then anyway

 

Drosera species 

Grow in a mix of equal parts peatmoss and fine crushed pumice or coarse propagating sand. Sphagnum moss is also suitable instead of peatmoss. Water either by automated spray system or else sit pots in trays of water and never let the potting mix dry out. Drosera prefer 30% shade through to 50% shade in mid-Summer. If grown indoors, then the plants need a North facing window with bright sunlight for as many hours per day as possible, and must not dry out.

 

Drosera filiformis and D.binata need to go dormant each Winter, and will survive heavy frost when dormant. When leaves become smaller in Autumn it is a good idea to put them outside for the Winter so that they go properly dormant. Drosera regia can go dormant but doesn't need to if provided with sufficient warmth and light.

 

Should your Drosera produce small or poorly formed traps, this usually indicates that there is not enough sunlight. If the tips of the leaves go black then there is not enough water or humidity in the air. Tentacles should have a reddish tinge which indicates that there is enough sunlight, while a fully green leaf indicates less than ideal light. 

 

Pinguicula

These prefer a better drained mix of 1 part peat to 2 parts pumice/coarse sand. They can adapt to a wide range of lighting conditions from indoor shade to nearly full sun. They do not need to go dormant in Winter, but will form small compact leaves as the weather cools. Can survive a light frost when dormant.

 

Potting Mix

Peatmoss can be obtained as the Hauraki Gold brand from Mitre10, or else from Oderings Nurseries. Do not use typical plant potting mix as these include fertilisers which are harmful to carnivorous plants. Mix peat with either fine crushed pumice, or coarse propagating sand, available from Mitre10.

 

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