The calla (Ethiopian zanthedeschia) are rhizomatous plants native to Africa, cultivated in Europe for centuries.
The white calla lilies are vigorous and rustic plants, which tolerate well
to be grown outdoors even in areas with a harsh winter climate; the large rhizomes are placed in a good rich soil, well worked, and are watered quite regularly,
avoiding to leave the soil constantly humid, as the rhizomes fear excessive humidity. They are placed in a semi-shady place, and generally do not fear the cold; if we fear that they suffer during the winter,
mulch the soil at the base of the leaves well, in order to preserve the rhizomes.
The colored calla lilies, on the other hand, are hybrids of less rustic varieties compared to the white calla lilies, for this reason they are grown outdoors
only in areas with mild winters; the rhizomes fear temperatures below 5-8 ° C, therefore in areas with a cool climate they are cultivated in ivnerno as house plants.
As with many bulbous plants,
during the winter months also the calla lilies go into total vegetative rest, and the aerial part dries up; in autumn we can therefore unearth the rhizomes, and keep them in a dark, dry and cool place, until the end of winter, when we will reposition them.