Oxalis--TOW

Robin Attrill robin@rpattrill.freeserve.co.uk
Tue, 11 Nov 2003 13:27:56 PST
Mary Sue et al,


>
> Another one I think is really beautiful not mentioned yet is Oxalis
> callosa.
>

I agree this is a lovely species, not uncommon in cultivation but frequently
labelled as Oxalis sp.  I think it is the best of the later flowering
species.

>
> I do have one question. My Oxalis have been very slow to come up this
fall.
> I planted most of them before I went to South Africa not wanting to have
to
> do it when I returned. It has been my observation that ones that have been
> out of soil and sprouted come up very quickly once you have potted them
up.
> In fact I recently received some from Uli that arrived looking a bit
> smashed. I think they all had roots and I believe almost all of them are
> now up and not showing any ill effects. Contrast that with maybe ten pots
> of other Oxalis that aren't showing any life and others that have only
come
> up in the last week or two. When I reported about the talk in South Africa
> people were saying they weren't dormant long and would immediately start
> growing with moisture. Any clues what is going on? I am tempted to unpot
> them all next year and not replant them until I see roots.
>

In addition to moisture I suspect that lowering temperatures are also
important for the winter growers. For example I've notice that pots of O.
versicolor, watered at the same time in autumn, come into growth much more
quickly if placed in a shady location out of doors relative to those in the
greenhouse.

As you point out bulbs of many species will produce roots and shoots out of
soil and can then be potted up as normal. I have not, however, come across
any species where this treatment actually confers a positive benefit. In
general they are remarkably resilient to robust treatment, both in and out
of active growth. In addition they are amongst the easiest of plants with a
dormant period in their annual cycle to transfer between the northern and
southern growth cycles - they seem to 'sort themselves out' in about 18
months.




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