Calla Lily - Zantedeschia



∙Water - 🔸🔸🔸

As Zantedeschias grow near ponds or rivers, dry soil is a rare sight. Although keeping them on the dry side will damage the plants longterm, be sure not to keep the soil too soggy as this will cause root or rhizome rot. Hydrate the plant once the top third of the soil dries out and if possible, try not to use cold water as their roots will be quite sensitive to temperature change. Either use rainwater, fresh bottled water or tap water that has been allowed to settle for over 24hrs to alleviate the ionised chemicals. The final tip is never to allow excess moisture to sit in the stems' cubbyholes; not only will it cause the foliage to rot away, but it may even result in pythium (bulb or rhizomes) rot. Either use the bottom-up method of irrigation or just be careful when hydrating the plant. Under-watering symptoms include a weakened stem accompanied by a loss of flowers, stunted growth and the greying or yellowing of leaves. These issues are commonly down to forgetfulness or too much heat or sunlight. Over-watering symptoms include yellowing of leaves, wilting, basal collapse, and plant death; these issues are commonly due to shady location that's too dark, excess moisture in the soil, a too water-retentive soil type or water-logging.


∙Humidity - 🔸🔸

A constant level of moderate humidity is best, as fluctuations could harm the plant over time. A weekly mist during the winter months is best to counteract the dry air caused by operating radiators. Botrytis or powdery mildew is caused when excess moisture settles on the foliage or flowers, harbouring harmful bacteria and fungi within the plant. Remove all affected flowers or leaves and maintain a drier climate. If your Zantedeschia is displaying signs of these disease, click on this link for more info on how to address them.

Identifying Common Houseplant Pests & Diseases


∙Location & Light - 🔸🔸🔸

An hour or two of direct sunlight is best for good quality growth. Never situate a Zantedeschia in dark locations as the chance of fungal or bacterial diseases are far too likely for such an expensive specimen. The frequency of irrigations solely rely on the amount of sunlight received each day; those situated in slightly darker locations must be far less than with those in strong light. 


∙Fertilisation - 🔸🔸

Use a fertiliser high in potassium to prolong its flowers during the festive period - an excellent example would be a Tomato Feed. Regular fertilisers, for instance, BabyBio or Miracle-Gro, will still do the job but will favour foliar growth instead. For the rest of the year, a standard fertiliser can be used to supplement the plant.



Common Issues with Zantedeschia

Spider mite are minute chlorophyll sucking pests that can reek havoc if left to manifest. Areas of attack are under the leaf, in circles and next to the midrib (central column of leaf). For more information on how to identify and address this issue, click here.

Browning leaf edges or tips are the result of too dry air; a good level of humidity is mandatory for a healthy specimen. Although misting the foliage is acceptable to keep the surrounding humidity high, never saturate the flowers as botrytis petal blight will develop. Click here to learn about how to keep humidity levels high and dying leaf tips at bay

Over-watering will quickly lead to the plant rotting below the soil line. Typical signs of over-watering include yellowing leaves, wilting foliage, a stem that's able to be pulled free from the rootstock and stunted growth. The roots, rhizomes or bulbs can all begin to breakdown if it's exposed to too soggy soil for long periods. As soon as the heart of the plant, (i.e. the bulb) begins to rot, its game over. To counteract this, allow the top third of the soil to dry out in between irrigations, with the avoidance of allowing excess moisture to settle in the plant's stems and cubbyholes above the soil line.

A lack of flowers could be due to an array of different issues that include irregular watering habits, too little light, not enough fertilisation or a poorly spent dormancy period. Cold water must not be used during the flowering period in summer as sudden temperature changes can shock the plant, preventing blooms. Although persistent droughts will also cause issues down the line, it's over-watering that must be considered. Abnormal growing conditions could cause problems with a Zantedeschia; avoid locations that are both too dark and too bright, and always provide a good level of humidity. Finely mist the foliage twice a week while keeping the flowers dry to avoid an attack from botrytis petal blight or powdery mildew. A poorly spent dormancy period could also inhibit the chance of blooms during the summer. For more information about how to set up the plant for a dormancy period, scroll down to the next paragraph.

A lack of flowers is caused by a insufficient dormancy period, served in the winter months. Locations that offer near-similar temperatures all year round won't allow the plant to go dormant, resulting in poor spring growth. To achieve, situate in a location that dips to around 10°C  (51°F) with fewer waters.




How to Get a Zantedeschia to Re-Flower & Its Dormancy Care

Shortly after flowering its foliage will begin to yellow and die off in late autumn. Prune the foliage back just above the soil line using clean utensils. Place the potted rhizomes in a dark location that provides low humidity and temperatures around 10°C  (50°F)  for a couple of months. Water sparingly so that the rhizomes are just 'ticking over' but keep in mind that too much soil moisture will cause root or pythium rot. Once foliage starts to reemerge in spring, weakly fertilise the plant using general plant food at half strength and switch to a potash-based feed after around eight weeks to promote flowers. Tomato food is an excellent choice to inhibit and prolong flower life. 




Origins

Zantedeschia consist of eight perennial species that originate from Southern Africa. The genus was first discovered in the late 18th century by Kurt Sprengel and was named in honour of Giovanni Zantedeschi, an Italian botanist and physician in the early 19th century.


Temperature

10° - 24°C  (55° - 75°F). Reduce this to around 10°C (50°F) during winter to replicate it's dormancy and to promote more efficient flowers in the summer.
H1b - can be grown outdoors in summer in a sheltered location, but is fine to remain indoors. If you decide to bring this houseplant outdoors, do not allow it to endure more than an hour of direct sunlight a day as this will burn the leaves. Regularly keep an eye out for pests, especially when re-introducing back into the home.


Spread

Up to 0.6m in height and 0.5m in width once they reach maturity. The ultimate height will take between 5 - 10 years to achieve.


Pruning

Remove yellowed or dying leaves and plant debris to encourage better growth and all-round growing conditions. When removing dying flowers or leaves, use clean scissors or shears to reduce the chance of bacterial and fungal diseases, and remember to make clean incisions as too much damage can shock the plant.


Propagation

Seed & rhizome division. To learn about the essentials with sowing seeds, be sure to click on this link - Seed Propagation Tips.

Division - Once the foliage has died back in late summer, split the rhizomes by either using your hands or a clean pair of secateurs. Some soil may have to be removed to get a better vision and grip. Transplant the rooted rhizomes in a moist, well-draining soil and place in a location that offers low humidity and temperatures around 10°C  (50°F)  for a couple of months. Water sparingly so that the rhizomes is just 'ticking over' - too much soil moisture will cause many diseases, including Pythium rot. Once foliage starts to re-emerge in early spring, weakly supplement the plant using a general plant fertiliser at half the recommended strength and switch to a potash-based feed (Tomato or Streptocarpus Food) after around six weeks to promote flowers.


Flowers

Most Zantedeschia will flower in summer, but the Z. aethiopica and Z. odorata will bloom from late winter until early spring. The flowers largely resemble that of a Peace Lily, with a coloured spathe protecting the spadix for pollination and enticing airborne insects. 


Repotting

During spring or summer, transplant every two or three years using a well-draining potting mix - this is an excellent time for rhizomatous division. For matured specimens, introduce slightly more grit to promote a stronger root ball; click on this link for more information on how to perform the perfect transplant. 


Diseases & Pests

Common diseases to attack Zanteschias are rhizome or root rot, leaf-spot disease, powdery mildew, pythium rot or grey mould (botrytis). Keep an eye out for aphids, spider mite, mealybugs, vine weevil & scale. Click here for more information about how to identify and address any of these issues.


Toxicity

This plant is classified as poisonous. If parts of the plants are eaten, vomiting, nausea and a loss of appetite could occur. Consumption of large quantities must be dealt with quickly; acquire medical assistance for further information and actions.


Retail Locations

Online Stores; most garden centres during late spring or summer. Check for pets and diseases when introducing outdoor plants into the home, replacing the top few centimetres of the soil for precaution.

Comments
* The email will not be published on the website.