Many of my plants are dormant in winter - because of the cooler conditions, particularly in the night. I keep them on the dry side but never let the soil dry out totally. Well, it may happen though, but the plants never stand bone dry for more than a day. I´ve heard of several losses in dormancy. In these cases people haven´t watered their plants for months. I´ve only read that this works when plants are kept outside and relatively cold - even perhaps down to freezing point. In Italy there are some very advanced growers of Petiolariscomplex species for whom it works. In Germany I guess keeping Petiolariscomplex outside in winter would most likely kill the plants.
There are some significant differences between plants in cultivation and in habitat. First is: In "winter" in Northern Australia it rarely rains, but the nights are getting quite cold and dense fogs are moving from the sea towards the inland. This is the reason why these sundew species (well not all of them
) develop petioles covered with lots of hairs. They filter moisture out of the fog which forms to perls of water on the surface of this fur and then run down to the centre of the rosette - providing the underground bulb with moisture. I actually do the same. I mist my dormant plants every three days - so that the surface becomes moist and about the upper 3 or 5mm of the soil. The pots are close under grow lights (~ 10 cm), so daytime temperature can still reach
26 -
28°C in winter, nights cool down to about
15°C. I don´t dare to let the temperature drop further down. I want to be safe.
If your soil is too moist and it gets cold - it can be the end of your plant, even just overnight! Had that once with my first
D. ordensis. It was shipped during a cold November night with wet soil. The plant died in three days!
D. paradoxa is more robust - it can take chilly temperatures and being in wet soil.
D. petiolaris is also relatively robust. But more sensitive than
D. paradoxa.
Another thing I was told is many Petiolariscomplex species grow in soils where lower layers contain clay. When these layers dry out they become a kind of isolation. Comparable to the habitats of tuberous and pygmy sundews. Petiolariscomplex species can also grow long roots which reach into these layers of clay. Below the thin isolation some moisture retains - just enough to keep the plants alive, if they should have died completely overground.
You can easily imitate nocturnal fogs for the dormant plants, but you would unlikely mix clay into your soil, would you? The question is would it work in cultivation as well as in nature!
When days are getting warmer in my climate the tub with my "Petios" is put back below my South-West roof window. They appreciate the direct sunlight! If you have
30+°C at daytime and at least
20°C in the night your soil can be permanently wet (during growing season of course). For you in Indonesia surely no problem! I don´t let the pots of my plants stand permanently in water! Nights can still drop down far below
20°C even in our summers.
In cultivation Petiolariscomplex sundews may not have certain dormancy periods - depending on climate. You can grow them for a couple of years without dormancy. From my American pals I´ve heard the plants can step into dormancy quite irregularly. Just when they fancy! Which can mean even in the middle of summer. Even a single plant or only two while your others (if you want hundreds
) are happily growing. Same can occur in winter! The rule is: If you watch a plant forming a smaller rosette stop watering! Let the soil slowly dry and observe the plant(s). If it stops growing or if it grows only petioles without trap leaves keep the plant dry, but don´t let it stay bonedry for several weeks. I´d recommend to take care that either the surface and a few mm into the soil have a little moisture every few days or alternatively you provide a few mm of water in the tray - for about one hour. Then put the pot back onto a dry place. If you watch the plant starts growing larger leaves start watering - a little first and then increasing.
Don´t force plants into dormancy by stopping watering when they are in full growth only because it´s "winter"!
They will show you when they need a dormancy. And they will show you when they wake up again.
This group of sundews like it hot, sunny, moist and relatively humid when in growth. When in dormancy they like a slightly cooler night I guess.
As for soil mix...well...I have no clue what you can get in Indonesia. I take peat 50%, and 25 % each perlite and coarse (lime free) quartz sand. Instead of peat you can take an equal amount of chopped dried (and dead) sphagnum moss, I´ve heard. There should be some coarser material in the soil mix to make it loose and airy.
Well, this is what I can tell you about cultivation of Drosera section Lasiocephala. Certainly I cannot guarantee that it works for you as well as for me, but I don´t know why not.
Regards,
Andreas
D. paradoxa is more robust - it can take chilly temperatures and being in wet soil. D. petiolaris is also relatively robust. But more sensitive than D. paradoxa.