Colocasia antiquorum ‘Black leaf Illustris’ is a large impressive colocasia known in the U.S.A as ‘Imperial Taro’ It is a really spectacular variety which with us, grown outside during the warmer months can and does reach 180cm high producing large leaves with attractive variable blackish centres with emerald green veins and outer margins. Extremely fast growing once the weather warms up this Colocasia does best planted in very fertile moisture retentive soil, we use a generous helping of well rotted horse manure to the planting spot. Happy in full sun to partial shade but try and avoid windy positions due to the size of the huge leaves which may become damaged.
Like most Colocasia, Colocasia antiquorum ‘Black leaf Illustris’ is not fully hardy although it will tolerate short spells of cool but not freezing weather it is best brought into a frost free position during the winter. Tolerating being dug up and placed into a container and kept just moist whilst dormant. It will remain evergreen given a little warmth and is happy in a cool room or conservatory. Given it’s large size leaves can be cut back to reduce size or if you are really short on space the swollen stem and growing point can be cleaned of compost and most of the roots then stored in damp compost at between 10-15 degrees centigrade until growth resumes in the spring. Unlike most of the Colocasia esculenta forms antiquorium tends to form a swollen stem in its dormant phase rather than the usual corm.