How to grow codiaeum

What are crotons?

Known as crotons or codiaeums (or botanically as Codiaeum variegatum), these are bold and colourful evergreen shrubs, native to tropical regions of Malaysia, Indonesia and Australia. When grown as houseplants, they need consistently warm temperatures, indirect light, regular watering and high air humidity.

Several cultivars are available, offering different leaf shapes, textures and colour variegations, including white, purple, orange, yellow, red and pink. The colours often form contrasting splashes or blotches or follow the veins of the leaves. Plants range from a compact 30cm (1ft) tall, up to 90cm (3ft) or more, depending on the

Gardeners often use the word variety when referring to a specific plant, but the correct botanical term is 'cultivar'. Whichever word you use, it means a distinctive plant or plants, given a specific cultivar name and usually bred to enhance certain characteristics, such as flower or fruit size, colour, flavour or fragrance, plant size, hardiness, disease resistance, etc. Additionally, it is worth knowing that, botanically, variety has another meaning - it refers to a naturally-occurring distinct plant that only has slight differences in its looks. For example, Malva alcea var. fastigiata differs from typical plants by having an upright habit.

Sap is a fluid that circulates through a plant's vascular system, in a similar way to blood moving through our veins. Phloem sap carries the sugars produced in the leaves by photosynthesis down to roots and other storage organs, as well as carrying minerals and hormones. Xylem sap is watery and transports nutrients absorbed by the roots upwards to the rest of the plant. Some plants leak sap from wounds or pruning cuts, and this is known as bleeding.

sap

Buying crotons

It’s usually best to buy plants in person, rather than online, so you can choose the leaf shape and colouring you prefer. These flamboyant plants are available from many houseplant retailers, with larger stockists offering the widest range of cultivars.

Choose a healthy-looking plant with lots of vibrant leaves and no signs of wilting or damage. As codiaeums are tropical plants, be sure to keep them warm while bringing them home.

Buying: garden centre plants

Buying: garden centre plants

Buying: mail order plants

Buying: mail order plants

Location

Crotons need bright but indirect light in summer to grow well. In insufficient light, the leaves may lose their vibrant colours or drop, but if exposed to full summer sun through glass, they may overheat and scorch. The plants will grow less in winter, when light levels are lower. 

Temperature

As codiaeums originate in tropical regions, they need constant warmth throughout the year, around 18–35°C (65–95°F). Make sure they don’t go below 15°C (55°F). Fluctuating temperatures and cold draughts can cause the leaves to drop.

Humidity

These tropical plants like moist air, so stand the pot over a tray of damp pebbles or ceramic clay granules – the water will slowly evaporate, raising the humidity around the foliage.

Wipe the leaves with a damp cloth occasionally too, to remove dust and help the plant absorb sunlight efficiently.

Watering

Water once the top layer of compost has dried out, preferably using rainwater at room temperature. Too much water can lead to root rot, so hold off watering if the compost is still damp to the touch and tip any excess away afterwards, so plants aren’t left standing in water for long periods.

Avoid using hard tap water on a regular basis, as this makes the compost more alkaline, instead of maintaining the acidic conditions that codiaeums enjoy. Use collected rainwater or softened water whenever possible.

Reduce watering in winter, when growth slows down – always let the compost be your guide, only watering when the surface feels dry.

Houseplant 101: Episode Four

Houseplant 101: Episode Four

Houseplants: holiday care

Houseplants: holiday care

Water: using softened and other types

Water: using softened and other types

Codiaeums can be tricky to keep in good condition, as they need high humidity and constant warmth. The main issues you may find are:

• Leaf drop – if your plant is losing a lot of leaves, it may be because the compost is too dry, or the air is too dry, the plant is in a cold draught or the temperature is below 15°C (55°F) for a long period

• Root rot – is caused by waterlogged compost, due to overwatering, leaving the pot standing in water, or using poorly draining compost (add perlite to improve drainage when repotting). Left unchecked, this can kill the plant
  
  

  

  How to help a poorly houseplant

  How to help a poorly houseplant

  

  Leaf damage on houseplants

  Leaf damage on houseplants

  

  Mealybug (Glasshouse)

  Mealybug (Glasshouse)