Calla Lilies

Zantedeschia ' Green Goddess' - Calla Lily
Zantedeschia ‘ Green Goddess’ – Calla Lily

Calla Lily season is in spring and they will flower for over a month outdoors. They are regarded

The Calla Lily is an easy care bulb or rhizome that produces attractive flowers in spring to summer. They can be grown in the garden however are equally at home in containers. In many zones this is a more suitable method for most gardeners as it makes them easier to protect over winter.

Although we call them Calla lilies, however they go by the botanical name of Zantedeschia, and the hybrids now available give us a colorful group of flowering plants

If we do a search for the botanical names we will come up with pictures of the white species, well known and widely grown. However it is the many colorful named cultivars and varieties that gardeners around the world are now using in the garden.

Zantedeschia aethiopica is the flowering species is often planted in wet or damp soils, although it does grow well in any good humus rich soil.

The new hybrids prefer drier conditions although they do like a humus rich soil with some moisture.

Although we see calla lilies almost year round in florist shops, flowering season in around June to July. The blooms appear as tight spathes, and they open to reveal the spadix.

Pink Calla Lily
Pink Calla Lily

Best picked for indoors before they open fully. And remember that these plants are toxic, so wear gloves and take appropriate safety precautions when handling.

Care

Calla lilies are a perennial rhizome or bulbous plant, evergreen to semi evergreen depending in the climate. Calla lilies prefer moisture and some resources say they need constant dampness, this may or may not be true. In dryer climates they seem to simply, go underground in summer.

Calla lilies grow well in full sun to part shade, however they do not like dry conditions. They also do not like wet conditions in winter, so a humus rich well drained soil that retains moisture. A position where they receive good morning sun and some afternoon shade works well.

Flowering season is in summer for cooler climates and spring to summer in warmer areas. They will die back over winter in all but the warmest zones.

In spring they will have reappeared and this is the season when most flowers appear, however they are are likely to bloom at other times, depending on the climate.

So a humus rich soil, moist in part shade and they are happy, some slow release fertilizer in spring and thats about it. Except for drainage, in winter they need good drainage.

Yellow Calla Lily
Yellow Calla Lily

Planting

  • Choose a position in full sun to light afternoon shade in warmer zones.
  • You need a moist but well drained soil, only the species Zantedeschia aethiopica really like wet soil.

  • If you have purchased the dormant rhizomes, plant them around 1 inch deep and 12 inches apart.
  • Water in with a liquid seaweed fertilizer.
  • When the flowering season is over it is important to leave the foliage to die back naturally, this puts energy back into the bulbs for the next flowering season.

It is also a good idea to deadhead the plants, this means that you will stop them setting seed, the calla will them put its energy into the bulbs resulting in bigger bulbs and better expansion of the clump.

Lifting and dividing

  • This can be dome as soon as the foliage begins to die back. If you live in a warm climate, with no freezes or heavy frosts then you can happily leave them in the ground.
  • In cooler climates you will need to either lift them over winter or provide some protection from the cold.

Varieties

The species is the white flowering Zantedeschia aethiopica, very common in older gardens. Zantedeschia rehmannii is the pink species and the yellow flowering Zantedeschia elliottiana.

Zantedeschia aethiopicaa ‘Green Goddess’ is one of the best known colorful callas, white with splashed of green, a real break in tradition from the single color white species.

However it goes a lot further than this with many hybrids also available as well as multi colors.

The hybrids are available in colors from white and pale pink through to orange, red and almost black. Many of these are hybrids of Z. rehmannii and Z. elliottiana.

The hybridized forms are often shorter growing and are favored by gardeners. The taller growing species are favored by the florist trade.

Problems

In general calla lilies have very few problems however sometimes gardeners will find that Calla Lilies will not flower. There are a few reasons why calla lilies do not flower or flower poorly

  • Firstly calla lilies need sun, those planted in very deep shade will struggle to flower.
  • Overcrowding is another problem. As clumps age they become overcrowded and bulbs compete for nutrients. Its time to divide the clump.
  • Using the wrong fertilizer. Using a fertilizer that is to high in nitrogen can cause the plants to put on lots of leaf growth and no flowers.Use a balanced fertilizer.
  • Bulbs drying out over spring to summer. Calla lilies like to have a moist cool root run, so bulbs that are planted to close to the surface or in dry soil will often decide not to flower. Plant a little deeper and mulch well.