Written by Fergus Masons • January 04 Calla Lily
The Calla Lily is one of the most distinctive wild flowers, but also one of the least likely to have found fame as a cultivated plant. It only occurs naturally in a quite small area of the world, and one that wasn’t well explored until the mid-19th century. However, our love of flowers has made it a popular plant that’s won fans everywhere for its simple beauty.
When we talk about gardening, a lot of the time we’re talking about flowers. The color and timing of blooms is an important factor in choosing plants, and a lot of pruning and fertilizing is aimed at getting the best display possible. Flowers matter to us and have done for thousands of years; even before the beginning of recorded history they were used in funeral rituals, and ancient writings describe them being given as gifts or used to decorate homes and palaces. The calla lily, however, seems to have been just another wild plant until Europeans started collecting them for cultivation.
First it’s useful to know exactly what a calla lily is, because it can be confusing. Botanists and gardeners have different definitions. Scientifically it’s the species Calla palustris, usually called Marsh Calla or Bog Arum, which grows in cool regions of Europe and North America. This is an attractive little plant but its small size makes it unspectacular and it’s also extremely toxic. Gardeners are more interested in a distantly related plant that makes a bolder display. This is Zantedeschia aethiopica, which was once thought to be a more exotic member of the Calla genus and still has the common name of Calla Lily.
The calla lily prefers much warmer weather than the marsh calla, because it’s native to southern Africa. In the wild it’s found in the southeast corner of South Africa, along with Lesotho and Swaziland, where it grows in and around streams and ponds. It’s an evergreen where the weather stays wet enough all year round but becomes deciduous if there’s a dry season. Even in the spectacular flora of Africa it stands out as one of the most attractive plants found around wet areas.
Where the bog arum grows to between six inches and a foot high the calla lily is a much larger plant. Some cultivars can reach three feet and its broad, dark green leaves can be over 18 inches long. What really makes it stand out is its large and unusual flower.
The calla lily’s flower grows at the top of a single straight green stem, and it’s highly distinctive. The yellow spike at its center is actually a spadix covered in hundreds of tiny yellow flowers, which give off a faint sweet fragrance. That’s surrounded by the spathe, which looks like a petal but is really a modified leaf, and that’s the really impressive part. It’s pure white, lightly furled round the base of the spadix and can be over nine inches long, and it gives the appearance of a white heart with the spadix nestled inside.
As European colonists spread through Africa they took the calla lily with them to help create beautiful garden scenes with Africa’s finest plants. It often found the climate to its liking and established itself in the wild, so now it can be found growing as far north as Kenya. The Portuguese also took it to the Madeira islands, where it thrives, and the British introduced it to parts of Australia. That wasn’t such a great idea, because it’s spread rapidly in Western Australia and is now classed as a weed there. That doesn’t make it any less beautiful, though, and it’s much sought after for flower arrangements. Traditionally the calla lily symbolizes beauty, purity and new beginnings, making it a favorite for wedding bouquets. It’s also associated with endings, though, so often makes an appearance at funerals too. They’re now cultivated for the cut flower trade, and millions are grown in California each year.
In much of the USA it’s possible to grow your own calla lilies outdoors. They grow from bulbs, and it’s best to start them indoors in late winter. Once the chance of frost has passed look for a location that gets bright sunlight in the morning, but ideally has some shade in the afternoon. Moist soil that’s rich in organic matter is best, and they’re quite tolerant of wet ground – they can grow in ponds, after all. Plant the bulbs about four inches deep, leaving a foot between them, and water them regularly. Apply a good balanced fertilizer every month, and they should grow rapidly. After they flower let them rest for around two months – the leaves will die back – then start watering again. The plant will reward you with flowers as long as the growing season lasts.
Because the bulbs are vulnerable to frost, if your winter temperatures fall below about 5%°F it’s best to bring the bulbs in for the season. After the first frost dig them up and discard the dead foliage, then clean any soil from the bulbs. Leave them in the sun to dry for a few days then store them in a dry place where the temperature remains between 50-60°F. When spring arrives and the danger of frost arrives you can plant them again and start over.
If you live in USDA hardiness zones 8 to 10 it’s a lot easier – you can plant calla lilies at any time of year and leave them in the ground, although if low temperatures go below 60°F you can apply a mulch of bark or straw. As long as the weather stays warm they’ll keep flowering, adding their simple beauty to your property. Calla lilies are also easy to grow as house plants and again will thrive all year round.
One thing to be aware of is that calla lilies aren’t benign. They’re safe to handle, but live plants contain high levels of calcium oxalate. Eating them can quickly cause a serious burning pain in the lips, tongue and throat, and swelling often follows. Stomach pains and diarrhea are also likely, so make sure they’re out of reach of children and dogs. Dry plants are safe, though.
If you’re attracted to the idea of growing calla lilies look at some of the cultivars available. Most have the classic and elegant coloring of a white spathe and yellow center, but there are variations. Green Goddess has green stripes on the spathe, and its large flowers last longer than other varieties. Red Desire has a red spadix, and while it’s hard to find it looks great mixed in with standard varieties. Pink Mist is similar but with a pink spadix and a delicate rose tinge at the base of the spathe. It’s trickier to grow, though, because it’s more delicate than other cultivars.
The calla lily is a beautiful plant, and not difficult to grow if you have the right conditions. It’s a striking and exotic addition to your garden and its large, simple white flowers will create a splash of brightness and serenity wherever you plant them. Use them to enhance a water feature or bring variety to borders, or mingle them with smaller bulbs for a sophisticated display. Whatever you decide to do with them, though, you’ll be delighted with these distinctive plants.