Dioscorea

Family Dioscoreaceae. About 600 species are known, mainly in the tropics of all parts of the world; a few species extend into temperate zones and montane belts.

Herbaceous or woody (in the tropics) vines with rhizomes or tubers. Female flowers solitary at the nodes of a spike; male flowers 1-7 in a semi-umbel or cluster at the nodes of a spike, raceme, or panicle. Fruit - a three-winged capsule with 3 locules that split at maturity. Seeds flat, with a broad wing on one, two, or all sides. Easily cultivated from seeds, tubers, and cuttings.

Location: should be sheltered from wind and situated in partial shade. These species tolerate bright sun poorly, but in full shade they develop significantly more slowly. Protection from frost is also quite important - frost damages Japanese Dioscorea and young plants of the Caucasian species.

Soil: loose, rich in leaf mold, moderately moist.

Care: They are demanding of soil moisture, so during drought they must be watered abundantly and often. Annual mulching with leaves for the winter is desirable. Young plantings are best protected from frost for the winter. Not affected by diseases and pests.

Propagation: by sowing seeds and division. Rhizome divisions at least 10-15 cm long are best planted in early autumn, when the plants finish vegetating. Dioscorea seeds do not tolerate drying well - they must be sown quickly. They require cold stratification, the best method of which is overwinter sowing in the ground or in wide boxes in a mixture of leaf soil and sand, choosing a partially shaded site. Young seedlings usually germinate uniformly, but late - in June to early July. It is important to carefully weed all weeds from the "seedbed". In summer it is good to feed the plants several times with a solution of mineral fertilizers (manure is undesirable). In the first year the plants are small (forming no more than 4-5 leaves), but their main task at this time is to build up the rhizome rather than the aboveground part. In autumn the seedlings should be set out into a bed for further growing at a distance of 5-10 cm from each other, renewing the substrate and adding long-acting mineral fertilizers. With good cultivation some plants already form small twining shoots in the second year, but overall the plants develop rather slowly and are ready to be planted in a permanent place only in the third to fourth year.