Weldenia candida

Dennis Szeszko dszeszko@gmail.com
Sat, 11 Feb 2006 19:21:48 PST
The other species of Weldenia (apart from W. candida) is Weldenia
shultesii.  (Angelo, thank you for looking it up.)  I have never seen a live
plant nor an herbarium specimen so I cannot tell you much more about it.
Apparently it is a valid specific epithet and not just a synonym of W.
candida.  I asked the preeminent expert on Mexican monocotyledons, Dr.
Adolfo Espejo, about this genus and he told me that both species names are
valid.  I agree that most botanical books will probably state that there is
only one species in the genus, but these books are either out-of-date or
written by people who do not work in the field in Mexico.

I cannot comment on the caerulea form of Weldenia candida because I have not
been lucky enough to find it.  I found one herbarium reference to it and it
was found in another state (Durango) about 800 miles from where I work
(Mexico state).  However, it doesn't make sense to look for the caerulea
form of a white flower when there are already so many pretty blue flowers in
the Commelinaceae family.  I say let the white flowers stay white and let
the blue flowers stay blue.  I have some pictures of Commelina species from
the wild with absolutely stunning true-blue flowers (dark sapphire-blue!),
but identifying these plants is very difficult because the literature is
vague.  As soon as I can figure out what they are I will post them to the

As far as I know, ALL of the Commelina species from Mexico have tuberous
roots that enable the plant to survive 6 months without rain. The plants
have finger-like roots much like Dactylorhiza and other tuberous orchids.
I've collected many plants of Commelina sp. thinking that they were orchids
when they were either sprouting or drying out because the roots look alike.
It's not until the first leaves emerge that the difference is apparent.

Interestingly, the plants of Weldenia candida in the wild do not offset like
they do in Bill Dijk's nursery/garden.  They form colonies of 10-15 plants,
but they are all seedlings that grew up around the mother plant.  However,
each plant is capable of producing many flowers at once which makes for a
beautiful spectacle.  The plant flowers just as new growth is initiating.
This is in contrast to most other plants in the Commelinaceae family that
flower at the top of mature growths.

The plant grows above 3000 meters (10,000 feet) but it rarely sees a hard
freeze because it is dormant during the winter (dry season).  Thus, it may
be possible to grow this plant in a cool but temperate environment.  The
plant is probably fairly tough (like other members of the family) but will
not tolerate any kind of heat (above 85 degrees) nor too much water during
its dormancy (I imagine).  I've seen it growing underneath Pinus hartwegii
so filtered light and a rich, acidic medium should be perfect.  (NB All
herbarium specimen collections were made in Pine, Fir or Juniper forests)


PS - As others have pointed out already, Dichorisandra thyrsiflora is
commonly sold as "Blue ginger" at garden centers.  However, the color of its
flowers is more purplish than blue and is not as pretty as the Mexican
Commelina species that I've seen.

> Dear all,
> I'm catching up with some of the latest posts. That was a beautiful
> picture
> from Bill Dijk of Weldenia candida. At this stage in my addicition I
> appreciate seeing pictures of things I shouldn't try to grow since they
> need such different conditions than I can easily give them so I shouldn't
> even think of wanting them. I am also grateful to Dennis Szeszko who did
> such a nice job of setting up the wiki page for Weldenia. Dennis if you
> ever get a chance to see the other species in the wild, it would be
> wonderful to have a picture for the wiki. I am sure you are correct that
> none of the rest of us would have much of a clue about it.
> Tsuh Yang asked: "but i guess i didn't know there were any that were
> tuberous or geophytical.  are there any others in the family?"
> This statement from Dennis is on the Wiki Weldenia page:
> "This rare and unusual genus belongs to the Commelinaceae family, or
> Spiderworts, that includes plants such as Dichorisandra, Tradescantia, and
> Commelina. " I've never heard of Dichorisandra, but aren't there tuberous
> or geophytic Tradescantia and Commelinas?
> Mary Sue

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