The Trouble with Arracacha...

I previously announced my successful overwintering of Arracacha cuttings.
So by now I should have the stout healthy specimens established outdoors, perhaps just flicking off the odd aphid, or casually hoiking an occasional weed from their mulch. But in fact they are still in pots, and under intensive care.
So what is the trouble? Well, I've been up some blind alleys trying to answer that. I noticed dieback of parts of the root system, along with yellowing then death of older leaves. Here's one plant during an unsuccessful examination for root-eating wildlife.

Here's a shot showing leaves at the stage after yellowing...

...Next comes complete death of the leaf. My guess is that the original cuttings carried some virus with them from Brasil, and given that the plants are now dropping leaves as fast as they grow new ones, I'm loosing hope of getting a crop this year. I should probably cut my losses and burn the remaining survivors.

But there is another approach...

A couple of plants have been determined to flower since mid winter.  The photo above shows the umbel-mounted tiny flowers in various stages of doing their thing.
If the plants stay alive long enough for the seed to become viable, this might give a route that leaves any virus behind, and give some plant variation, with all of the benefits that brings.

So probably no Arracach fritters this year then.

Update. All plants died by Spring. Darn it!

Overwintering Arracacha — Mustering the Survivors

Back in the Autumn I described (here) how I obtained Arracacha cuttings from Brazil, and was faced with the tricky problem of keeping them alive through a winter when they had just been plucked from Brazilian spring. Well, despite the particularly miserable winter, I think I am now in a position to confidently declare the survivors safe, seasonally syncronised, and ready for the growing season. Here they are...

Overwintered Arracacha, 2nd March

But it has been far from straightforward. The rooting and initial growing-on went easily enough. In fact, it seems that rooting can be successful even in relatively unfavourable conditions. Fellow gardener Ale Abrao, by way of illustration, placed cuttings outdoors in rubbly soil, with just an open-ended polythene cloche to keep off the worst of the winter.

Cuttings outdoors, 21st November

Four weeks after their October planting, they are growing away well despite some pretty grim weather conditions — near freezing, and grey cloud cover. These plants seemed reassuringly tough, and were doing almost as well as my mollycoddled indoor-grown specimens...

Rooted cutting, 7th December

But then the days got shorter, the light levels dropped, and the coldest winter for many years set in. Ale's 'outdoors' were finished off by -10°C temperatures. My plants stopped growing (apart from a few that bolted) and began to look yellow and sick. Here they are in mid January...

16th January

Many died, wilting back and rotting at the roots despite my efforts to give them light, warmth and dry feet.  By early February less than a third of the original plants remained.

But then a few cuttings which had apparently died, but not actually rotted, started to show signs of regrowth...

Apparently dead plant showing regrowth,  2nd March.

This one looked like a goner, but is reshooting from its central stem, and there is a tiny green bud, just visible, growing from the base.

Ale's plants, including his indoor ones, did not make it.
Back in October I also sent backup cuttings to Rhizowen and Frank van Keirsbilk. Reportedly they have both had the same difficulties as me; the latest news is that between them only one plant has hung on (well done Frank). Admittedly their cuttings were not as fresh as mine, having sat for a while, then suffering additionally in the post.

So, what next?  It's certainly still too early to plant out ( only 3°C  today), so they will staying in the greenhouse for a while yet.

The next target (apart from the obvious one of obtaining an edible crop) is to grow them through to autumn, then lift and store crowns to produce propagation material in late winter. The timings for this are all a big unknown, but are key to adapting this crop for growth in northern latitudes.

Given their noticeable tendency to flower in winter (I think induced by short day-length) I will also attempt to collect some seed for distribution this time next year.

Brazilian Arracacha Arrives

Arracacha (Arracacia xanthorrhiza)... may require some introduction. It's a high-yielding starchy root-crop popular in southern Brazil, and parts of the Andes. A member of the Umbelliferae family, and sometimes called the Peruvian Parsnip, it forms sizable crowns with several good-sized edible roots growing below, and propogation shoots above.
All sounds good so far, but it's another crop that has failed to make an impact outside its home territory, probably because of the tricky combination of frost tenderness, and a required growing season of up to 14 months.
Reports are divided on whether it is day-length sensitive.

So... these are arracacha propagules - unrooted buds cut from the plant's crown. This is a named variety, 'Governador Amaral', recently developed in Brazil to have a short growing season — short enough perhaps to crop in a temperate climate such as the UK.

Just like the black Oca which I received recently, these cuttings are seasonally desyncronised, having just been whisked from Brazilian spring to English autumn. I have gleaned enough information to know that they would probably just rot if I tried to induce dormancy using low temperatures, so I'm going to have to try to get them rooted, then nurse them through the coming winter.

Here they are installed in a cozy propagator.
There are bound to be some casualties but if most of them root, I'll have some little plug plants to spare for my friends.

UPDATE 9/11/10
After a couple of weeks, almost all of them have burst into vigorous life, above ground at least. Checking the cut surface of a couple reveals a few short roots starting to reach down into the compost.

They have been spending the nights (and colder days) indoors, in the propagator under a window, but whenever the sun shines and the greenhouse warms up a bit, I'm moving them out to catch what daylight is available. I've even washed the greenhouse glass especially for them!

UPDATE 22/11/10
Almost all have rooted well, and made nice little plug plants. I used a very sandy open compost to minimise the risk of rot, and the roots have raced down through it.

Had I used a normal plug tray with such a crumbly compost, it would have been almost impossible to remove the plugs intact, but the process was, as always, trouble-free using a self-ejecting Agralan plug tray.

I'm potting on promptly to avoid a congested root ball, just in case it results in humorously distorted comedy vegetables at harvest time. Peruvian folk-lore would apparently suggest that this can be a problem; the recommended precaution for growers there is to avoid sleeping with crossed legs during the planting season.

Mission accomplished with regard to rooting. Now I need to slow them down till spring comes, so I'll leave them in an unheated greenhouse from now on, only bringing them indoors on really cold nights.