Zantedeschia, the florists’ arum

Wide-reaching leaves, and flowers elegant enough to cut for a vase: the florists’ arum (Zantedeschia aethiopica) settles as happily at a pond edge as in a flower bed or an indoor pot. Its one real demand is a full two months of dormancy without a single drop of water — meet it, and the plant blooms year after year.

Zantedeschia at a glance

Name	Zantedeschia aethiopica
Family	Araceae
Type	rhizome perennial
Height	20 to 32 inches (50 to 80 cm)
Exposure	full sun, part sun
Soil	rich, well drained
Flowering	early summer to mid-autumn outdoors

Also used as an indoor plant, it is quite easy to care for and blooms year after year outdoors and indoors. Follow our advice to produce magnificent zantedeschia:

Planting Zantedeschia

Zantedeschia bulbs are planted at the beginning of spring, around 1 ½ to 2 inches deep, from early spring to late spring.

• Space bulbs around 12 to 16 inches (30 to 40 cm) apart, because zantedeschia has wide-reaching leaves and needs space.
• Choose a location that is in full sun but stays cool.
• Don’t plant in very dry soil, because zantedeschia requires cool, moist soil.

• At a pond edge, Zantedeschia aethiopica will happily sit in the boggy margin with its base under a few inches of water.
• Wear gloves when handling unfamiliar rhizomes: some, such as those of aroids like Alocasia and Colocasia, contain needle-like calcium oxalate crystals, while others irritate skin and mouth through different compounds.

Watering your Zantedeschia

Watering outdoor zantedeschia

You can grow your Zantedeschia outdoors provided you observe a period of dormancy of at least 2 months within the year without watering a single drop.

• After the blooming, reduce the watering until the leaves turn yellow.
• When the leaves have withered, stop watering altogether.
• Slowly start watering again at least 2 months later.

Water sparingly at the beginning and then more regularly once flowers have appeared, until the end of the blooming season.

Arum grows very well adjoining a body of water, which indicates how much it needs water.

Take note, though, that the term used for this plant is semi-aquatic, because it does need a water-free period of at least 2 months, generally during summer.

Watering indoor Zantedeschia

You can grow your Zantedeschia indoors, in pots, but again you must respect a period of dormancy of at least 2 months within the year without watering a single drop.

• After the blooming, reduce the watering until the leaves turn yellow.
• When the leaves have withered, stop watering altogether.
• Slowly start watering again at least 2 months later.

Pruning and caring for zantedeschia

• Cut short just when the first frost spells hit.
• Do not cut before leaves have turned completely yellow, since this is the span of time when they are building up their nutrient reserves for the next blooming cycle.

For spectacular blooming, add special bulb plant fertilizer.

• Wear gloves when cutting back: zantedeschia sap contains calcium oxalate and irritates skin, eyes and mouth.
• For many common spring bulbs such as daffodils and tulips, a balanced feed is generally applied from shoot emergence until the leaves yellow, including the weeks after flowering while foliage remains green.
• Use a clean, sharp blade: standard pruning practice favors smooth cuts over ragged, crushed tissue, which is generally considered slower to seal and more vulnerable to disease than a clean wound.

Protecting Zantedeschia in winter

Zantedeschia is quite hardy even in cool winters.

In areas that are prone to cold winters, protect the rhizomes with a thick layer of mulch.
The mulch can either be a bed of dried leaves, hemp or flax straw, or ferns.

• For many rhizomatous perennials such as bearded iris, winter losses commonly stem from waterlogged soil rotting the rhizomes rather than from cold alone, which is why growers prioritise sharp drainage.
• For bearded irises on heavy clay, replant the rhizomes on a slight mound or raised ridge so water drains away from the crown, since sitting in cold wet soil encourages rhizome rot.
• With winter mulch over perennials, bulbs or strawberries, gardeners are commonly advised to pull the covering back gradually once the first shoots appear, so emerging growth is not left damp and crowded.

A video on caring for Zantedeschia

• All parts of the zantedeschia contain calcium oxalate crystals, so wear gloves when dividing rhizomes and keep the plant away from pets and small children.
• Slugs feed on the young leaves of many garden plants in damp weather, rasping irregular holes in them; because they shelter by day, check under pots, boards, and plant debris after rain.

Potted zantedeschia, how to care for it

Once the leaves are completely yellow, you can cut them to the shortest.

• Remove the bulb from its pot, cleaning the dirt off delicately.
• Set it for the winter in a cool spot where it doesn’t freeze.
• This storage spot must also be very dry and dark, for example a small shoebox with a ventilation hole pierced in it.
• In early spring, you can bring your bulb out and plant it again in new soil mix.
• Start watering again when the soil is dry and your arum will bear flowers again.

You can also stow the bulb or rhizome away without removing it from its pot, but the soil mix needs replacing every two years anyway.

Propagating your Zantedeschia flower

When provided with rich soil that is full of humus and sufficient sun and water, Zantedeschia tubers (roundish rhizomes) will multiply underground:

• In the dormant phase, when the leaves have died back (a couple months after blooming), unearth these tubers.
• Spread them apart to cover more ground, about one to a foot (every 25 cm).
• Don’t bury them too deep: ensure the top of the tuber is just under the soil surface.
• Protect the rhizomes or tubers from the cold with a thick layer of plant mulch.

They’ll grow back in the following season and keep multiplying year after year.

The zantedeschia year: what to do and when

Zantedeschia follows a simple cycle of growth, flowering and a compulsory dry rest. Here is what each stage asks of you.

Respect the dry rest and the same cycle repeats, year after year.

Which zantedeschia to choose

Some zantedeschias are tall, hardy white types for a damp border or pond edge, while others are shorter, brightly coloured forms better suited to pots. This comparison should help you pick the right one for your spot.

Learn more about Zantedeschia

This bulb perennial is native to South Africa, not from Ethiopia as its scientific name seems to imply.

It grows naturally in damp marshy areas that are drenched during the rainy season and dirt dry during winter.

Particularly exotic, it is perfectly suited to wet areas like water bodies and ponds, and it’s also the perfect plant for your flower beds, edges or standalone spots.

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