Oca: Frost tolerance

Mexican Red looking pretty sad after light frost

We planted out the oca (Oxalis tuberosa) a couple weeks ago and since then have experienced a couple of very light frosts.  When I say light frost, I mean the sort that just barely appears only on the lowest areas of the garden – in frost pockets.  Very little of what we grow is affected by such light frost, so I don’t give a lot of thought to frosts at this time of year.

I know that oca is frost sensitive, but my experience has been that it is not particularly vulnerable to light frosts.  Of course, I am growing a lot more varieties now, and they don’t appear to all be equally robust, so it appears that I will have to reassess that position.

Several of the varieties were damaged by the frost.  The most significantly damaged was Mexican Red. They lost some of their lower leaves and all of the leaves significantly yellowed.  They are looking pretty bad, but after a few days, the leaves haven’t dropped, so I’m hopeful that they will recover.  The stems don’t look damaged, so this may just be a set back.  BK08516.8 and Golden also took some damage, but primarily to the lowest leaves.

BK08516.8 showing damage to lowest leaves

Meanwhile, Hopin, Sunset, and Bolivian Red look no worse for the wear.  Those are the only varieties that are up in significant numbers at the moment, so I can’t evaluate the rest.  In all cases, I had multiple plants of each variety that showed the same level of damage (or lack thereof), so I think that coincidence is unlikely, although this is certainly not a large sample size.

This may help to explain why Hopin is such a common variety among the oca suppliers in the Pacific Northwest.  If Mexican Red is a Mexican variety as the name would suggest, then it may make sense that it has less frost tolerance.  That may explain why it seems to be a very common variety in California.  Assuming that it exhibits the same level of frost sensitivity at the end of the season, Mexican Red may not be the best choice for the Pacific Northwest and similar climates.

At any rate, clearly there are some significant differences in frost tolerance among the available varieties.  I will add this information to the oca profiles on this site.

Hopin looking unaffected, other than a bit of rabbit sampling

Oca seeds and tubers are sometimes available from our seed shop.