Date: Tue, 21 Mar 2000 13:35:23 +0000 From: Phil Wilson <cp@pwilson.demon.co.uk> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg798$foo@default> Subject: Re: Huh? Summer dormancy?
Hi,
>
>I'm worried about some of my sundews, namely Drosera cistiflora, D.
>manni and D. sewelliae. All these need a summer dormancy, don't
>they? But I have "germinated" these in winter, and now that the
>weather is warming, they are growing, when they should be starting
>to rest (my D. menziesii have flowered and are already dying, so I
>guess it's time to rest). What should I do, then? Let them grow?
>I don't understand the pigmy drosera life cycle. When do they
>produce gemmae? I want that my D. sewelliae produce gemmae before
>they enter dormancy. And the flowers? The D. manni are flowering,
>will they enter automatically dormancy after that? Or must I
>trigger dormancy?
>
Your plants will enter dormancy when they are ready to. Do not try to
force them into dormancy. Before going through dormancy the plants will
need to build up reserves. You will probably find the plants start
entering dormancy within the next few months. The two factors which seem
to trigger this is daytime temperature and photoperiod.
If your plants have only just started to grow again you may have kept
them too cold over the winter. While most of the winter growing Drosera
will take a slight freeze and are certainly okay at temperatures around
5C they will not actively grow. I prefer a day time average of about 8
- 10C allowing the temperature to drop to around 2-5C at night.
Pygmy Drosera produce gemmae once they have started to grow again - i.e.
after dormancy. Mostly pygmys will start to go dormant once they have
finished flowering. This does not apply to all species or even to
individual plants.
Once your plants are dormant reduce watering but do not entirely dry the
pots. The aim is to keep the dormant plants damp enough to prevent their
death and dry enough to prevent rotting. The exception is D. cistiflora
which can be allowed to dry out but also does not seem to mind a
slightly damp dormancy.
The pygmys will restart growth on their own. Do not try to coax them out
of dormancy by watering too early. As with dormancy the trigger to get
the plants growing again seems to be a drop in temperature and a
reduction in the daylight length.
D. cistiflora is again different. In my experience you need to re-wet
the pots to get the plants back into growth. I usually start watering my
plants at the end of August and expect to get above the ground growth by
the beginning of November (though quite often this is sooner).
Hope this helps.
Phil Wilson
Email: cp@pwilson.demon.co.uk
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