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Plant Profile: Pencil Plant

Euphorbia tirucalli

Picture of a Potted Pencil Plant

Pencil plants are an easy plant to grow especially in a pot. Photo Credit: Robert A. Putnam County Master Gardener Volunteer.

Euphorbia tirucalli (pronounced you-FOR-bee-ya tie-roo-KAH-lee) commonly known as Pencil plant is relatively easy plant to grow in North Florida.  It is well adapted to drought conditions; it enjoys full sun and has few pests.  It can be easy to propagate and can be shared with friends.  There are a few points of caution to be aware of, but over all this plant is fairly low maintenance.

Plant Biology

As a Horticulturalist I just couldn’t get by without a short botany lesson.  Let’s start with the most referred to common name, Pencil Cactus.  Common names tend to mislead people when it comes to the nature of a plant.  It can be said that this plant is a succulent because it stores water in leaves, stem, and roots.  However, it is not a cactus.  Remember all cacti are succulents, but not all succulents are cacti.  Pencil plants are actually in the Euphorbia Family whose best-known member is the Poinsettia.

Top of a Pencil Plant showing the small leaves

Having leaves is one of the main reasons that Pencil Plants are not Cacti. Photo Credit. Vicky K. Putnam County Master Gardener Volunteer.

There are actually three reasons that Pencil plants are not cacti.  First, Pencil plants have leaves.   They are very small, develop at the tips of the plant, and quickly fall off. The second reason is, Euphorbs (a shorthand for the Pencil plants family) have thorns that are actually modified stems, whereas cacti have spines which are modified leaves.  Finally, the last difference is that Euphorbs ooze white sap when they are cut.

Words of Caution

Speaking of the white sap, be careful when cutting or handling a pencil plant.  Ephorbs’ sap, like members of the Ficus family (fig and rubber plants), contain latex.   The sap can cause major irritation to the skin, eyes and cause severe irritation to the mouth and digestive system if ingested.  According to the ASPCA this plant can cause irritation to the mouth and stomach as well as vomiting to you pets.  Seek veterinarian attention if you suspect your pet has eaten a part of this plant.  For more information, please visit https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/pencil-cactus.

Care

Pencil plants are really easy to take care of and often prosper with neglect.  North Florida, it best to keep this plant in a pot.  Frost and freezes can kill this plant, so you will need to bring it in during cold spells.  Like most potted plants, especially succulents, the next major problem is watering.  These plants like the soil to get fairly dry between watering.  You can tell when it needs water by either using your finger to check if the top 1 inch of soil is dry or wait for the plant stems to start to droop.  Water the plant more often in the summer (growing season) and less in the winter.

Remember the symptoms for overwatering and underwatering look the same (curling leaves (if present) and drooping stems).  If you are keeping them outside in a pot for the summer make sure you keep an eye on both the soil and the plant.  Any sign of stress mentioned check the soil.  If it is fairly wet, you will need to move it to an area that gets less rain.

Propagation

Creating new Pencil Plants is fairly easy and is best done in the summer.

  1. Make sure your sharp cutting instrument (pruner or knife) is sterilized to prevent any fungal or bacterial infection of your cutting.
  2. Wearing gloves cut at least a 6-inch piece off your plant.
  3. Allow it to air dry and callus (typically 4 days to a week) on a sheet of paper towels  or newspaper.
  4. Fill a small pot (4-6 inches) with already moistened soil and make a hole with a pencil or dowel.
  5. Place your cutting into the soil (if you prefer you may use some rooting hormone, but usually it is not needed) and firm up the soil around the plant.
  6. Do not water until the top 2 inches feels dry otherwise rot will set in.
  7. In about a month you should have good root formation and your plant can be slowly moved outdoors.
For more information about propagating plants

3 Comments on “Plant Profile: Pencil Plant

  1. This pencil plants have done real well in containers in our yard in South Florida.

  2. I can not find a picutre of my plant. I think it’s some sort of pencil plant, but not sure. If I take a picture of it, can I email it to you and see if you can help me with it? It’s very fast growing and needs very little care. Also wondering if I should stake it up to re-inforce it. I would like to have your e-mail so I can send it to you.
    Thank you. Judy