One of our focus areas for crop experimentation is Tropical Perennials Grown As Temperate Annuals. Many of the crops that we can sustainably grow in Western NC and beyond are root crops because we can store the dormant root over the winter and re-sprout the following spring. If you’ve ever sprouted your own sweet potatoes then you are already are well acquainted with growing tropical perennials as temperate annuals!
Within this general focus area there are a subset of root crops that have their native home in the Andes (which is not all tropical). The world-known ‘Irish’ potato has a strong Andean heritage and Peru, Bolivia and Ecuador are home to an incredible diversity of potatoes. There is a sub-species referred to as the Andean Potato, which we’ll talk about below. But beyond the potato there exists a whole host of edible root crops from that region.
A key resource for these plants is William Whitson, owner of Cultivariable. Whitson has spent a lot of time and energy working with these crops as an independent plant breeder. His aim is to release disease free, improved varieties that will work well in a North American environment. I highly recommend visiting his website and listening to his podcast for an insight into his work.
Oca (Oxalis tuberosa)
Oca is a challenging plant to grow in the Southeast for two main reasons. First, it doesn’t really like it when it gets hot (much above 80F), so getting the plants to survive happily through the summer can be problematic. Second, the tuber formation is triggered by short days, which means a late winter harvest is needed to maximize yield. Sadly, in a normal season, our first frost will kill oca before significant tuber production…
This year we have 10 tubers planted from Cultivariable breeding stock, which have been selected (among other things) for longer day length tuber formation. These are actually ‘breeding-seconds’, which means they didn’t make Cultivariable’s cut but are good trial material for us in the Southeast. We have successfully grown oca in buckets before, which meant they could be moved around to maintain optimum conditions and protected from early frosts. This year we’ll try a mix of planting methods and plant protection.
Mashua (Tropaeolum tuberosum)
Mashua has a similar story to oca in terms of sharing many of the same challenges that exist for other Andean root crops, the main one being short day tuber formation. Mashua is basically a tuber forming nasturtium, which you may recognize from the leaves in the picture above. Nasturtium (Trapaeolum spp.) is widely grown; The common garden flower nasturtium is often T. majus, but mashua is T. tuberosum speaking to its tuber forming talents.
We are growing two released varieties from Cultivariable:
Ahahawat tubers are large. At full maturity, they are light yellow with purple eyes. Harvested before full maturity, they are white, with just a little bit of yellow at the tip. The flavor is excellent, slightly sweet with no bitterness or flowery aftertaste. I think it is one of the best mashuas that I have tasted.
Chockalilum tubers are pink, ranging from white with just a little pink when immature, to fully pink or even darker red at full maturity. They have a relatively low density of eyes, which means less cleaning. The flavor is fairly cabbagey and will probably remind you of Brussels sprouts. It lacks any bitter or flowery aftertaste. The texture is soft and the tubers will break down with long cooking time.
Yacon (Smallanthus sonchifolius) aka Bolivian Sunroot
We have been growing yacon for a few years in WNC, using propagation material from board member, Yanna Fishman. Yacon is an Andean crop that does not seem to mind the summer heat and forms a good amount of storage tubers by first frost. The small propagules are separate to the edible tubers, so you can eat everything you harvest and just save the small propagules for replanting the next year.
This year we are exploring some additional varieties from Cultivariable (notice the theme here!).
There is a lot to like in this variety, but I selected it for release based on the fact that it is an early flowerer and carries the genetics of Cajamarca, which is a difficult variety to work with. It is about a month earlier to flower and form tubers than the next earliest variety, Bekya. The roots are medium sized, white/tan, and sweet, smaller but otherwise similar to Cajamarca. It sets seed with a compatible pollinator. It is medium to tall with green stems. It isn’t a particularly high yielding variety, but I think it will be a good variety for climates with shorter growing seasons. It will probably do better in containers than larger varieties. The smaller root balls are also a lot easier to harvest than those of heavy yielding varieties and smaller roots are a more practical size for fresh eating than two-pound monsters.
Sol Duc has a moderate yield, with an average of eleven pounds of storage roots. It has red skin and develops skin color relatively early, so that the tubers are all red at harvest. In most varieties, color develops late and many of the tubers are still white at harvest and require a week or more of exposure to color up. Sol Duc will continue to grow darker with exposure, becoming nearly black in some cases. The flavor is among the sweetest at harvest and continues to intensify in storage. Sol Duc flowers abundantly and sets seed easily, but is not early to flower, beginning in October.
Quinault is the first new variety introduced from our breeding program, grown from open pollinated seed of the variety ‘Rojo’. Mature tubers come out of the ground a light/red purple, sometimes partly tan, but become the darkest red of any variety that we grow after a couple weeks of exposure. Plants are of medium height, usually reaching between five and six feet here by the end of the growing season. The one purpose that this variety is not suitable for is as an ornamental. It is a slovenly looking plant with sprawling stems and droopy leaves. That doesn’t affect food production, of course, but it is a better plant for the back yard than the front.
Achira (Canna edulis)
Achira is another Andean root crop that doesn’t mind the summer heat. Canna indica is perhaps the better known ‘Canna Lilly’, which is planted as a landscaping plant that produces beautiful flowers loved by hummingbirds. Canna edulis has been selected for the edible rhizomes, which can get extremely large and are used commercially in starch production.
The picture above shows Achira on the left and Lerenes (we’ll talk about that next time) on the right.
We have been growing one variety for a few years, supplied by board member, Yanna Fishman. It has beautiful foliage. This year we are stepping up production to explore more culinary uses of the root.
Andean Potatoes (Solanum tuberosum subsp. andigenum)
The Utopian Seed Project volunteered to be part of a participatory breeding project for Cultivariable. That basically means that we received 100 seeds of an Andean Potato cross which we’ll grow out. William Whitson has some specific qualities he’s looking and so we’ll make assessments at harvest and send back the best of the tubers for him to continue his work.
True Potato Seed (Solanum tuberosum)
This is our first time growing potatoes from seed. With the knowledge that each plant will be producing a brand new potato variety, it’s quite an exciting project, kind of like hunting for gold. However the chances of stumbling on something better than what is currently available is quite small… Still, True Potato Seed (TPS) offers an introduction of wide genetic diversity, which is something potato growing is lacking. So we’ll see if we strike gold at harvest!
As spring progresses, we’re getting close to transplanting outside, although this morning was 26F in Leicester NC, so still some indoor babying to do yet! Field prep starts next week…