Oxalis recommendations?

Mary Sue Ittner msittner@mcn.org
Sat, 08 Nov 2008 13:27:02 PST
I too am an Oxalis fan and every year give offsets to the BX. I'm just 
passing on the generosity of Mike Mace who shared many offsets in the 
beginning from his IBS Michael Vassar collection. I still remember him 
describing his delight when his wife gave him the collection as a present 
and how he stayed up late planting them since they were already growing. A 
lot of Oxalis enthusiasts are very generous with their extras. Bill Baird, 
Uli, and Ron Vanderhoff have all shared with me too. And Diana at Telos 
sells a lot of wonderful species so it isn't hard to get started (at least 
in the US) and much too easy to become addicted/passionate.

I've found the winter rainfall species from South Africa do best for me if 
I start watering them in August which is earlier than I start watering most 
of my winter growing bulbs. This means that the early blooming species can 
start flowering in September and put on a dazzling display of color during 
the often sunny days we have in fall. Besides the bright colorful flowers 
and the long blooming season, I also love the variety in the leaves. Oxalis 
pes-caprae is the one to watch where I live where it has naturalized and 
taken over in many areas of coastal California. Oxalis purpurea is likely 
to spread and be hard to eradicate too for me if planted in the ground. It 
also doesn't bloom for me in the shade which a lot of my property is so I 
regret the few experiments where I tried it in the ground, beautiful though 
it may be. However, if you have a place where you don't care if it takes 
over, it is carefree and blooms for a very long time. I've tried a few 
Oxalis in the ground like obtusa and they have disappeared. I've grown 
others in pots in raised beds where I haven't repotted them and have had 
better luck with a few species like O. flava and O. luteola, but they don't 
bloom quite as long it seems as when they are repotted each year. At least 
that's my experience.

Living in an area with a lot of winter rainfall and dark days, I expect my 
plants will never have the tight form that plants do in South Africa and 
southern California. I often grow a number of them in a cold frame where 
there is sometimes just enough extra warmth to have the flowers open in 
winter. Oxalis gracilis is not a strong bloomer for me and Oxalis 
inaequalis was an early casualty. I did see it bloom briefly one year and 
was surprised how huge the flower seemed in relation to the size of the 
plants. So neither would make my favorite list although I like the color of 
Oxalis gracilis.

I think my ten would have to be influenced by which was blooming at the 
time so if you asked me at different times of the year I might give 
different answers. But I share some of the favorites that others have 
mentioned and it's difficult to choose since ones I don't have on this list 
I'm very fond of:
Oxalis bowieii -- fall bloom, large bright pink flowers for a long time
Oxalis convexula -- I like the succulent leaves of this species
Oxalis elegans -- summer growing species from Ecuador from Uli, or at least 
that's what we think it is, long blooming in summer, could be hardy if you 
stored it appropriately since I just leave mine dormant in winter and don't 
start watering until spring
Oxalis flava -- fall bloom, lots of variety in leaves and flower color, 
long bloom
Oxalis hirta -- nice fall blooming plants although they need a deep pot
Oxalis peridicaria (syn. O. lobata): I too love this one from South America 
with its bright yellow flowers
Oxalis luteola: I have three forms of this one, one with spotted leaves 
that does not offset much. I love all three.
Oxalis obtusa: Some years some of the forms I grow bloom for three or four 
months. Lots of great variety in these, but there is a pink one that 
appears in a lot of pots and I wonder if it seeds itself about
Oxalis palmifrons: Grown for the leaves
Oxalis versicolor: Another favorite in bud and flower

Mary Sue

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