Gladiolus cardinalis

Gladiolus cardinalisThis wonderful gladiolus species comes from the Southern Hemisphere and it can’t seem to forget its native seasonal rhythm.  This  poses a cultural quandary in this country for growing it in the open ground.  The reason is that it starts growth in the autumn and  produces new shoots that break the surface, often as early as February.  If we then experience a spell of sub-zero temperatures, these new shoots will be killed off and it will take a while for replacement growths to develop.  At best this will delay and reduce the flowering, or worse, stifle it completely.

This has been the pattern over recent winters here, and although the corms are unlikely to be killed outright, it poses the question of how to get the best display from this spectacular plant.  It is not suitable to treat it as a hardy perennial plant left to its own devices.  It can of course be pot-grown in cool greenhouse conditions. There is also the option of putting some form of protection over the newly emerging growths before winter sets in, and this may work.  But a preferable option is to lift the bulb colony around October time, divide it into good sized groups, pot them up and keep them just moist in a frost-free place, before planting them out once the risk of frost has passed.  Some vigorous new growths will already be present in October and these will quickly emerge at the surface.  Given a good long season of growth, these are almost certain to produce their magnificent flowers in late summer.

In this way the seasonal rhythm is preserved and the little trouble that it takes to over-winter the corms is amply rewarded.  Plant in an open, sunny position and if, by some miracle, we have a hot, dry summer spell generous watering will be helpful – after all it is not called the Waterfall Gladiolus for nothing!