Oxalis in bloom etc

Matthew Mattus mmattus@charter.net
Sun, 10 Oct 2004 15:37:54 PDT
I've been a little lazy lately in the greenhouse, especially during the dog
show season. So I have been late in watering the oxalis, that we're spending
the summer up on a higher shelf out of reach. They had their first rains
last week, since I placed them outside to get drenched with the remains of
the Hurricanes that we had. Since I don't fertilize most of my South African
bulbs, I took the opportunity for the natural rain while it was still mild.

It's surprising how quickly they emerge, I haven't repotted them except for
a few (more about that later), and they are still growing in a mixture of
Pumice and sand, as directed by Michael Vassar a few years ago.

Emerging OXALIS include Oxalis pocockiae, which has sent out long thin
singular stems each with a single blossom, all before any foliage, and I
also have a few buds on my O. commutata, which does have emerging foliage

Oxalis that are just showing foliage emerging now are also O.obtusa "rose",
O. zeekoeviensis, O. luteola, O.imbricata, O. hirta, O, purpurea , and my
tiny and lovely O.palmifrons, Oh, and my VERY favorite, O. braziliensis,
which when in full foliage looks more like a mounded bun of an alpine plant
than an oxalis.

Now, when Michael Vassar spoke at the IBS Symposium a few years back, he
insisted on using a soil mixture for Oxalis, that was much more closer to
the soil that they grow in in South Afican, basically a low nutrient mixture
of Sharp sand and pumice. I know that many of thse oxalis will also thrive
in a richer soil, but that they will become monsters with lush foliage and
such. However, I must note that some of what appear to be escaped O.obtusa
or errant O. purpurea became deposited in sime of the larger tubs of citrus
in the greenhouse last winter, they we're spectacular, to say the least, one
orange flowered O.obtusa also ended up in the rich soil of a hanging plant,
and it over shadowed the plant with incredible flowers.

This year I repotted some O. purpurea hybrids and O. obtusa hybrids into a
richer yet fast draining mix that I use for my fritialra and crocus
collections, basically Ian Youngs' mix of one part leaf mold, two parts
granite chips and two parts loam, with a touch of bone meal. I added some
sharp pool sand to keep the mix dryer. I'll let you know what happens.

Not that I like big showy hybrids, but these examples sure beat the  single
flower at a time that I would get from the same plants in the Pumice
Mixture. I believe that certain Oxalis species do wel one way or the other,
but I am looking for advice as to which Oxalis and what soils have other
used to achieve a desired look. Many of my species I will, of course,
continue to grow in the pumice mixture, it keeps them tight and dense. But
which ones should I try experimenting with? Any thoughts?

Matt Mattus
Worcester, Massachusetts, USA Zone 5
Where "Margaret" our little Irish Terrier won Best Of Winners at the
National Terrier Specialty at Montgomery last weekend. :)

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