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Petiolaris complex

  • #21
I've grown most members of the complex and have a few thoughts to share. I agree with most of what has been said but offer a word of caution regarding repotting. There is an urge when plant is doing well to repot into larger containers. In my experience this is not always wise, and especially so for the petiolaris plants. Rapid growth and offsetting in my collection often happened prior to the plants heading into dormancy. The moisture content in the pot needs to be reduced in increments *as soon as signs of dormancy are noticed*, so that the pots are just moist by the time new growth ceases. I found plants growing lustily one month quickly shut down growth. Too much moisture in the pot and you get crown rot and plant loss. The larger pots take longer to dry off, and the time difference can spell success or failure. I would suggest a largely inorganic medium that can be quickly dried out, and close attention to signs of incipient dormancy, and recommend that the plants be kept in smaller pots for this reason. I haven't run any controlled experiments, its just a gut level feeling. I also haven't been able to determine any rhyme or reason to the dormancy triggers: some plants shut down in winter, some in summer. I believe that uniform warmth with little differential between day and night temps. *may* contribute to forestalling dormancy, but it isn't an absolute. I have watched large offsetting plants take a nose dive within a month, so there is little forgiveness. I also recommend plants not sit in tray water, but be given water only when the need is apparent. For me, the plants did respond to higher than normal levels of humidity, and were grown outdoors in terraria with covers open a few inches while avoiding night time drops by applying bottom heat as necessary. It meant a lot of fussing in my area since the differential is 5-10 degrees even in summer.
 
  • #22
Hi CP2K,
Nice plants & nice photos - thanks for sharing these and your info.

In your post, you bring up an interesting point on heat:
[b said:
Quote[/b] ]....I've been growing Drosera paradoxa from seed to flowering plants within 6 months in an outdoor terrarium that is 75% covered(traps the heat but not much of the humidity). It seems like the perfect place for cactus, rather than Drosera.
Otherwise, I have an indoor setup consisting of a large plastic container covered partly with some saran wrap(again to trap heat rather than humidity). The container sits on a heat mat....
Obviously most of the longer-term growers of this group seem to find that higher heat is a good thing for Pet complex plants. My question - where is the upper limit? When I hear about terrariums outside in the LA sun, it really makes me wonder how high of temps these plants can handle. Have you ever stuck a temp probe / thermometer in there? Or better yet - a digital max-reading thermometer? I really don't want to find out the hard way what the upper limits are by finding 'mush' when I get home.

We know that there is a limit as Pingman found with some D. falconeri cuttings/divisions (from a 2002 post):
[b said:
Quote[/b] ].... There were many basal leaf segments that were knocked loose in this process and I placed the smaller crown and the loose pieces into wet, long-fiber NZ Sphagnum Moss in a small translucent plastic box with a lid of the same material. I kept the plastic box within 2 inches of a 100-watt incandescent light. Disaster, this time I had the light too close and when I checked the "propagation ward" everything inside looked mushy, brown, and dead. I almost cried. But I moved the container farther from the light and ....
Based on my [limited] personal experience, I've measured 107-108*F (42*C) in my terrarium in the sun and the plants loved it (or so it seemed). I suspect that the max is much higher - what temps should start to cause nervousness? And is the high temp related to the humidity (plants can stand higher temps in higher humidity)?

I think I've read a Seandew post that his greenhouse sees 45*C (113*F) temps in the summer with no issues (is that the temp the plants see?)

Just since my original post on humidity - I've opened my top more and allowed the setup to dry out between waterings and the D. lanata has resumed its previous growth and none of the other plants have suffered (still early but looks promising)...
 
  • #23
Hi Ron,

One of the reasons I never completely seal the terrarium is because the temperatures would be too high. I have tried growing paradoxa in a sealed terrarium outdoors in full sun. In the winter and spring, the plants grew fine, however, the plants died back during the summer. I did not record the temperature, but the pots were almost too hot to handle.
 
  • #24
Hi Tamlin,
[b said:
Quote[/b] ]The moisture content in the pot needs to be reduced in increments *as soon as signs of dormancy are noticed*, so that the pots are just moist by the time new growth ceases. I found plants growing lustily one month quickly shut down growth. Too much moisture in the pot and you get crown rot and plant loss. The larger pots take longer to dry off, and the time difference can spell success or failure. I would suggest a largely inorganic medium that can be quickly dried out, ...
Thanks for this info. In researching old postings, I've come across similar recommendations (seems that a lot of people lose plants during dormancy
smile_h_32.gif
). One thing that has bothered me with these recomendations is how to do it...

If I've got small pots with a mostly inorganic media, that I want to dry out failrly quickly - how do I keep them from drying out completely and killing the plant? Everyone seems to say to keep the pots slightly damp during dormancy. At 90*F+, things can dry out pretty quickly. Maybe it's just the years of growing all the other VFTs, Drosera & Sarrs that have me really paranoid. Many times, when they completely dry out, they're dead. Just a few weeks ago, I had to take a trip and be away for a few days. I tried to give detailed instructions to my family but when I got home, I noticed that a small group of D. rotundifolia that was growing larger than anything I've grown before - were dead (one has since resurrected).

Are plants in the petiolaris complex naturally more resistant to being dried out - so they can handle it better than other plants I've grown? As I've noted previously, I've slowly been experimenting with lower humidities (with pretty extreme paranoia) and getting decent results so far....
confused.gif
 
  • #25
Hi Ron,

Well, daily watering is just about a must when growing in those hot conditions so it's a matter of attention and focus. I think that seed grown plants can probably take extreme heat (at least extreme heat here in cool upstate NY) if they are started in those conditions. I grew all the common Drosera started from seed in a glass covered bin with maybe 3 inches between the substrate and the glass which was cracked no more than 1/4 inch. The bin was 8 inches deep and sat in about 6 inches of water. After heavy rains the plants were submerged for days on end. The bin sat in full sun, and all the plants prospered like no other method I have used. If these species can take it as hot as it must have been I am sure the petiolaris would as well. I believe it was the humidity that was essential to the success and the fact they were all started from seed in the naked outdoors. I feel that there is a corresponding relationship between high temps and higher humidity (makes sense: in habitat the higher temps would mean higher humidity). As far as a upper limit goes, well, just because something can survive doesn't mean it is optimal. I never tried to push it and aimed for a 90-100F range with good results. I always used correspondingly warm water when watering in the evening. So in a nutshell, the hotter it got the more I aimed for higher humidity. As to areas where the sunlight is more intense a different protocol is probably needed - here we get only some 40% available sun. I can't imagine growing them enclosed in Arizona or California, but then again I never expected my bin experiment to produce the results I got. MAybe if the enclosing space were small enough it could be possible, but at 20-30.00 a pop for plants who can afford to experiment?
 
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