Dumb Cane Care Instructions

Dumb Cane

Scientific name: Dieffenbachia
Synonyms: Dumb Cane

Dieffenbachias are relatively easy-care plants with large, broad, patterned, oblong leaves. There are many varieties of Dieffenbachia, from small, almost dwarf types (best for table-tops) to large plants that can reach heights of 120cm (best used as floor plants). As they are generally large and showy plants they are widely cultivated as decorative plants.

Dieffenbachias are fairly versatile and will take some neglect and poor treatment, but not too much. Additionally, they are fantastic at regenerating themselves if you have to start over.

They are commonly known as Dumb Canes due to the toxic sap which inflames the tongue and throat, if digested, causing a temporary inability to speak.

Note: All parts of the Dieffenbachia are poisonous and should be kept away from pets and children. Always wash your hands after handling.


Common Symptoms

  • Stem soft and discoloured are signs of overwatering. Or a combination of overwatering and low temperatures. Remove the affected stems and adjust watering/room temperature accordingly. If the damage is too severe you will have to discard the plant as rotting cannot be reversed once started, however, you can try to propagate the plant by using the top parts as cuttings.
  • Brown leaf Edges are a result of overwatering or underwatering. You should be able to assess the problem by looking back on your watering schedule. Remember to only water again when the soil has dried out a little from the previous watering.
  • Brown leaf Tips / Water forming on leaf tips: If you find water-like droplets have formed and collected on the leaf tips wipe the water away with a tissue before it dries as the water droplets contain various salts from the plant that will cause leaf burn if left to dry.
  • Pale or scorched leaves occur if the plant is exposed to direct sunlight or very bright light. First, the plant’s leaf colours will begin to fade and if the plant is left in that condition for a prolonged period, scorching will result. Cut the scorched sections out, or remove the leaf entirely and find a new space for your plant.
  • Yellow leaves, dropping off: This can be due to 3 things:
    1. This is a normal sign of aging.
    2. However, if multiple leaves are affected at once this is a sign of too low temperatures, or that the plant has been placed in a draughty area.
    3. Yellow leaves can also occur when you are consistently overwatering.
  • Pests: Scale, red spider mites, and aphids all enjoy setting up home one the Dieffenbachia plant. Scale and Aphids can be removed with a soapy spray, though you may need to do this a few times to totally remove them. Red spider mites normally only appear if the humidity is too low, so keep it as high as possible to deter them.
  • Plant is leggy (stem becomes naked) when the plant looks like a bunch of stems with foliage on top (kind of like a tree) then the plant has not been pruned enough during its lifetime. Remember to prune Dieffenbachias to keep them full and bushy. The topshoot (foliage on top) can be cut off and rooted: See Propagation instructions below.

Care Instructions

  • Origin: New World Tropics: Mexico and all the way south to Argentina.
  • Height: Grows up to 120cm
  • Light: Dieffenbachias require medium to bright indirect light, but should be kept out of direct sunlight to avoid leaf burn.Remember to rotate the plant regularly to provide adequate light to all sides of the plant.
  • Water: Water when the top few centimeters of soil are dry to the touch. Reduce watering during the colder months. These plants do best when watered on a regular schedule.
  • Humidity: Dieffenbachia Plants prefer high humidity, but still does well in average household humidity. Increase humidity by misting the plant or placing it among other plants.
  • Temperature: Temperatures of 16-27°Care ideal for the Dieffenbachia. Try to keep the plant always warm. Keep the plant out of cold drafts and away from cold sources such as air conditioners or windows.
  • Soil: Use well-draining rich organic mixture.
  • Fertilizer: Feed your plant with half strength balanced feed only when it is actively producing new leaves. Most Dieffenbachias should be fed every two weeks in summer and once a month in spring and autumn. Never fertilize the plant during winter.
  • Repotting: Dieffenbachias like to be a little pot-bound. However, when the roots have filled the entire pot you can repot the plant in spring into a new pot that is only a little wider (about 2-4cm) than the old pot. Repotting the plant into a larger pot will allow it to grow taller, so keep that in mind before repotting. You can repot the Dieffenbachia at any time of the year.
  • Pruning: To create a fuller, bushier Dieffenbachia, aggressively prune your plant. Pruning the plant also keeps it from getting too ‘top heavy’ due to leaf growth.
  • Propagation: Division – medium difficulty. If the plant is bushy with lots of stems coming from the soil, you can divide it into smaller plants. Gently pull the clump apart, making sure each section as some of the original root system and pot.

    Cutting 1.1 – easy difficulty. As the plant gets older and taller you sometimes find bare stems near the base of the plant. Remove one of these stems and cut it into chunks of about 5cm. Push these chunks into free draining compost mix, about halfway. Water well and keep warm. After several weeks you should see new growth sprouting.

    Cutting 1.2 – easy difficulty. If the stem you have cut off (see above technique) has a crown of leaves on top, you can try root it by planting the crown into a free draining compost mix and you might find that new roots will begin to grow from the bottom. Keep it warm and moist (but not too wet else rotting may occur).

If in stock, shop for Dumb Cane here.

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