Calathea Picturata ‘Vandenheckei’
The Brazilian species Calathea picturata is less frequently grown than the cultivar C. p. ‘Vandenheckei’, which is now considered to be the juvenile phase of the plant. The species itself has long, oval, dark green leaves, marked with streaks of white and yellow along the midrib and around the edges; in the cultivar shown, these markings take on a silvery appearance, with the central midrib thickly drawn and the leaf margins carefully feathered and scalloped; each leaf underside is of a rich purple. All Calathea need steady warmth and a high degree of humidity to maintain the health and appearance of the striking leaves; they are worth the effort for the diversity of form and leaf patterns available. This cultivar is one of the smaller Calathea available and, as such, is one of the better selections for the modern home.
High and constant temperatures are essential. During the Spring and Summer growing period, provide 17-21°C (65-70°F); Winter temperatures should be maintained at above 17°C (65°F). C. p. ‘Vandenheckei’ benefits from good, draught-free ventilation during hot weather.
In Winter, keep this plant in good, indirect, light, and in light shade during the growing period.
Use tepid, lime-free water, keeping themoist at all times, but avoid over-watering. Water regularly, reducing the amount when temperatures are low.
All Calathea benefit from a daily misting: in addition, place the pot on a bed of moisture-retentive pellets, contained in a 5cm (2in) tray; keep the tray half-filled with water to increase the humidity level around the plant without the risk of over-watering.
Feed this plant every two weeks with a proprietary houseplant fertilizer at half-strength; do not feed newly-potted plants for six weeks .
Repot overcrowded plants as necessary; most will need repotting every other year: use a lime-free compost, and only pot-on into the next pot size up. If the root is overwhelmed by the amount of compost, the plant will be more difficult to water correctly.
As a group of plants which benefit from warm, moist air and shady conditions, Calathea can be used to best effect in a North- or East-facing conservatory.
Crisp brown leaf margins result from too little humidity.
Botrytis (grey mould) may result from a lack of ventilation and a very ‘muggy’ environment; ventilate regularly without exposing to draughts.
Drooping and limp leaves will occur if conditions are too cold.