bluemax

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It seems to me that there is a lot of interest in sundews of the petiolaris complex but not a lot of information out there. I consider these plants to be some of the most beautiful and interesting of all Drosera, if not all plants. They continue to be rare in cultivation and expensive to buy when they are available at all. Many consider them to be too difficult to grow but the irony is that once you have found a way to provide them with the continuously warm temperatures and high humidity they require they become quite easy to cultivate. It would be nice if more growers were able to enjoy these plants from close up. I hope this can be a place where information about petiolaris sundews can be exchanged, questions can be asked and growers can post their photos. There are many threads about this group of plants but nothing really encompassing yet. So - what do you have?

I can start with this. These are photos of my set-up in a 10 gallon aquarium tank. If the plants look kind of ragged it's because most have been divided lately or still need to be.

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This one's Drosera lanata.

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Tacks

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Great idea for a thread! I've been interested in Petiolaris sundews since I saw the picture of D. derbyensis on the Wikipedia page on sundews, but I've held off as I try to get better at growing the easier subtropical species. I am looking at building a couple new grow spaces soon though, and something geared toward the Petiolaris group is at the top of my list.

Could you describe your setup in more detail? I'm particularly curious about your lighting, circulation (that looks like a computer fan on there) and supplemental heat (if any). Also I can't tell if you're using tray watering or not. Thanks a lot!
 
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Great idea. I'd love to see information about: seed germination, guiding through dormancy, heat and cold tolerance, and perhaps where to even get some from. They seem impossible to find anywhere domestically.
 

bluemax

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@Tacks: D. derbyensis is a beautiful plant. I still haven't seen that one in the flesh. As for the setup, sure thing. I think it could be done more simply but I have a tendency to deal with the variables one at a time. This produces a sort of piece-meal approach.

The lighting is 2 24" T5 florescent tubes with a reflector. Because it seems to cause the plants to lose their dew if the cover glass, which is just regular window glass, is allowed to get too hot the fixture is 3" - 4" above. I could use a bit more light for that reason.

Heating is provided by a heating mat, of the kind you use to germinate seeds, attached to the back of the tank behind the aluminum foil wrapped on 3 walls. There is also a low-wattage aquarium heater in a glass jar filled with water and a plastic lid to keep down evaporation. This heater uses only 7.5 watts and runs continuously without a thermostat. It is of the kind designed for small fish bowls. This is important because thermostatic heaters will heat the water in the jar to the preset temperature and then shut off. The room the tank is in becomes quite chilly in winter so I need the extra heat. I also have styrofoam insulation on the 3 walls with the foil to keep in the heat. In a warmer room a lot of this could be eliminated. I feel it is critical to keep the temps over 70F. and I prefer that they never get below 80F. A daily high in the 90's to low 100's is my aim.

The plants are indeed watered by tray. They sit on a raised egg crate platform that has water below it as well. The computer fan blows down through this and helps to raise the humidity while providing circulation. It was too powerful and created way too much air flow originally so I have cut off about 80% of the impeller blades.

I would love to know how others grow the petiolaris 'dews. There must be simpler ways.

@Jimscott: That's Vancouver, Washington State. We're across the Columbia River from Portland, Oregon.
 

bluemax

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What it all comes down to for me is the petiolaris sundews need all the regular things sundews need: relatively high light levels, lots of water and fairly standard Drosera soil. But what they need besides is humidity in the 70%+ levels and temperatures that never go below the 70's F., unless you are intentionally inducing dormancy. How you produce these conditions can vary a lot. In truly tropical climates they can be grown out of doors.
 

Cindy

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This group of plants go dormant when the Australian summer hits them in the wild (like how pygmy sundews are dormant except autumn and winter) but they went dormant during the coolest months for me at the balcony. My ambient conditions ain't that different from where they originate from so I was confused.

Then I found out that they go dormant too during low light levels (usually the case for the year end months with loads of rain). And this dormancy often results in losses. Last year, I kept them going with high light levels under T5 lights. Seems to work so far.
 
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beautiful plants, they are hard to come by here in AU, same with N.Tenax and Rowanae, they are native yet are almost impossible to get in AU, also although most petiolaris die down in the dry season I have seen wild Lanata growing in the heart of the dry because they found permanent wet seeps.
 
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Excellent growing! That D. linata is a beauty. Thanks for sharing your setup, its always nice to see how others grow their CPs.

Happy growing;
Victoria
 

bluemax

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Then I found out that they go dormant too during low light levels (usually the case for the year end months with loads of rain). And this dormancy often results in losses. Last year, I kept them going with high light levels under T5 lights. Seems to work so far.

That is news to me and I've never heard of low light levels causing dormancy in other Drosera. Petiolaris 'dews are different in many ways, it seems.

beautiful plants, they are hard to come by here in AU, same with N.Tenax and Rowanae, they are native yet are almost impossible to get in AU, also although most petiolaris die down in the dry season I have seen wild Lanata growing in the heart of the dry because they found permanent wet seeps.

I'm surprised that they are hard to come by in Australia. I believe there is a vigorous CP community there. 'Cool that the D. lanata plants can grow through the hottest of the summer given water. That would explain their love of heat.

Excellent growing! That D. linata is a beauty. Thanks for sharing your setup, its always nice to see how others grow their CPs.

Happy growing;
Victoria

'Glad you like the photos. I am hoping to see what others have done.
 

Cindy

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That is news to me and I've never heard of low light levels causing dormancy in other Drosera. Petiolaris 'dews are different in many ways, it seems.

Yep, that is from the growing experiences of the growers here. We all thought it was temperature at first but we are hot year round...hardly even warm by temperate standards. The plants go dormant at about the same time as the Vfts and Sarracenia and after checking with each other, we do think light plays the biggest part. During the year end, we have reduced light levels because of the rains. And also since most of us are apartment growers, a change in season sometimes mean light no longer shines directly into the growing area for a few months. We haven't been able to validate the "theory" as there aren't that many garden growers who have their petiolaris complex plants growing in the open to compare with. These plants are hard to come by so most of the growers keep them indoors and protected from the torrential rain. LOL
 

bluemax

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Cindy - It would be interesting to try out lowered light levels under artificial lighting and see if one gets the same results. On the other hand I avoid dormancy like the plague. As you mentioned you never know if the plants will wake up at all. I have heard that there are growers who induce/allow dormancy year after year. Do they just deal with the losses or have they figured out how to minimize them? I wonder.
 

bluemax

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D. paradoxa temperature question

Drosera paradoxa is the most tolerant, or at least one of the most tolerant, petiolaris sundews when it comes to cool temperatures. They will continue to grow in temperatures that have other species completely shut down and dormant. Has anyone watched D. paradoxa become dormant due to low temperatures? If so, at what temperature did the plant(s) become dormant?
 

Cindy

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Hi mark, there is lot of literature pertaining to the plants going dormant in summer in the wild. But I haven't read anywhere that they go dormant with low temperatures or low light levels...These are experienced by temperate and tropical growers as well. Have you come across any literature about cold dormancy?
 

bluemax

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Hi, Cindy. I haven't, and I'm just assuming that dormancy could be induced this way. I make such an effort to ward off dormancy that I have only seen two species go dormant and never D. paradoxa. Having done some quick reviewing I've found one source, the AIPC publication The Petiolaris Complex by Maurizio Saroldi, states that D. paradoxa remains growing in a diminished form during the dry season in its natural habitat. This makes me wonder if this species has the capacity to go dormant. Have you seen it do so?
 

Not a Number

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There isn't much day length variation at the latitudes these are found 12-18°S, maybe 1.5-2 hours either way at the most. The lowest average temperatures that I can find in the area is 13°C (55°F). More typical is around 18°C (64°F) in the winter. Mean monthly rainfall can be as low as 1.2mm during the winter.

My plants experience winter temperatures at night around 64-68°F (18-20°C). The only ones that have ever gone dormant on me are D. paradoxa. It has been remarked by other growers that D. paradoxa seems to go dormant at random times. Light on the tank are on 14 hours a day. I do not vary the photoperiod but there is plenty of ambient daylight too. They seem to flower on cue around the same time each year.

Lowrie mentions that the soil takes on an almost concrete texture during the dry dormancy period for some of the species in one of his papers.
 

Cindy

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We experience random dormancy by D. paradoxa too...which is why we do the divide and conquer strategy. Manual divisions for backups against losses. LOL
 
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I know D.Lanata can get nights as cold as 5-6C in winter, but this is normally only for a few nights at a time, and the days are still in excess of 24C, so I would imagine it would have to get pretty cold for a sustained period to induce a dormancy, there is a population near a town called Herberton, and they have recorded temps as low as 1-3C, but 5-6C is the coldest I have ever recorded at a location with them (west of Mareeba near a mates place) and it is never sustained for more than a few nights.
 
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Also there is a rumour that -5C was recorded at Herberton, but I am yet to meet anyone who can confirm it.
D.Burmanni, Indica, Banksii, Spathulata and Utricularia Limosa, Nivea, Uliginosa, Bifida, Aurea, Gibba and a few other utrics also live there.
 
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