Not recommended for growing in USA - Zone 5a regions
Yacon is perennial in sub-tropical/tropical areas. Save some root pieces and treat as an annual in other areas.
Grows into a large plant ( about 2m/6ft) with flowers similar to sunflowers and Jerusalem artichokes.
The plants die down after frost but the roots are sweeter. To store, dig and dry out for a couple of days in the sun if possible. Store in a dry, cool, not freezing and dark place.
Any roots left in the ground will grow the following year except where there are frosts.
The large roots can be used raw in salads peel and chop. Sprinkle with lemon juice to prevent browning.
'In the Andes, they are grated and squeezed through a cloth to yield a sweet refreshing drink. The juice can also be boiled down to produce a syrup. In South America the juice is concentrated to form dark brown blocks of sugar called chancaca.' (Green Harvest)
We cannot help if you are overrun by giant slugs.