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Corydalis sewerzowii - plant of the month April 2017

Corydalis sewerzowii - several different spellings of the name occur, the original being sewerzowi - is a semi-desert plant from mountain foothills, favouring steep clay slopes. It comes from the area formally known as central soviet Asia - Tadjikistan, Uzbekistan and Kazakhstan at between 500 to 1700m. To overcome the harsh environment and climate where it can be found and in common with other members of the section Leonticoides, C. sewerzowii has developed a relatively large tuber with a 'corky' outer skin which is found buried deep in the rocky soil. The growth cycle in this environment is by necessity rapid; the shoots develop from autumn through winter and emerge as the local snow melts in early spring. Flowering, seed set and tuber growth needs to fit into a window of around 2 months before the climate becomes to inhospitable for active growth above ground.

Cultivation needs to take these adaptions into account. Bulb frame culture is by far the best way to accomodate its needs; an unrestricted root run with the tuber planted at a great depth (30-50cm) gives the best results. because the shoots tend to travel outwards for a distant, pot grown specimens tend to flower around the edges of a pot rather than from the centre. Good light is also very important - poor light quality and quantity leads to elongated stems which extend and hang over the pot in an untidy manner. Temperature has less of an effect if the tuber is planted deeply; new shoots may be killed off by late frosts but a mature tuber will remain unharmed. Because the tubers do not divide naturally, seed is the best method of propagation. In common with a number of species in this section, C. sewerzowii is self-incompatible; it needs two separate clones to produce viable seed. Fresh seed sown gives good results and flowering sized plants can be expected in the fourth or fifth year.

The base colour of the flowers of C. sewerzowii is yellow, with the long spur often flushed brownish-red, characteristically straight but recurved at the apex. flowers can be as long as 4.5cm in mature specimens. The grey-green foliage, biternate with divided leaflets is an added bonus to this attractive species

Ray Drew