Pencil cactus is an interesting but poisonous houseplant

I get a lot of questions about poisonous plants. Many

species, both interior and exterior can contain poisonous

chemicals. Most aren’t a major concern. In fact, many of our

common houseplants are considered poisonous, but they are found

everywhere. Often, we see them in public places frequented by

pets or small children.

Poinsettias are common Christmas decorations, and they have

poisonous latex in them. If we get this latex on our hands and

then rub our eyes, we’ll be sorry. However, the same can be said

for touching habanero peppers.

Elderberries are quite poisonous prior to ripening. In

large quantities, nutmeg can cause dizziness, drowsiness and

seizures. Apple seeds and cherry pits contain cyanide compounds.

Potatoes exposed to light contain glycoalkaloids. These can even

cause death. Raw cashews contain the same compound found in

poison ivy.

Pencil cactus (Euphorbia tirucalli) is a poinsettia

relative. It has a reputation for being extremely poisonous.

I’ve even had folks ask me why we have it in our greenhouses.

The answer is simple. We keep poisonous cleansers under our

sinks. Who worries about that? We even eat foods containing

poisonous components like the ones already mentioned.

I wouldn’t place pencil cacti around unsupervised toddlers

or puppies, but they are an attractive and intriguing houseplant

for well-lit places. The white latex is the only toxic part, and

these plants have no thorns.

They’re great in succulent dish gardens, but after a year

or two, they often must be separated and planted by themselves.

Eventually, they can become large. I’ve seen these Euphorbias

well over six feet tall indoors.

Pencil cacti require very little maintenance and they can

be pruned without causing harm to the plant. The white sap can

be a skin irritant to some. It will cause severe eye problems

for most people.

People allergic to latex are especially susceptible to eye

irritations, and in some cases have even gone temporarily blind.

Corneas can be totally burned out. I wouldn’t recommend people

with latex allergies to keep this plant or others containing

latex. Otherwise, washing with soap and warm water immediately

after handling will remove the toxins and avoid any problems.

Pencil cacti are also toxic to pets. The sap can cause

irritation to the mouth and digestive system, but generally,

toxicity is overrated. Many other plants like daffodils are

potentially a greater concern for pets. Oleander, Aloe vera,

castor beans and tomato foliage are common plants that can be

problematic for canines.

Ingesting the sap from pencil cactus is not common.

Numerous articles warn us that it’s toxic, but the sap is so

bitter I doubt even the most curious toddler could tolerate

swallowing enough to be life-threatening.

Dumbcane is another houseplant often touted as extremely

toxic. It contains calcium oxalate crystals, which cause burning

and tongue paralysis. Symptoms are mild and temporary, and I

suspect children and pets wouldn’t consume enough to hurt them.

We have houseplants for decoration, and pencil cacti make

striking contrasts to our other plants. Furthermore, any plants

with latex are likely to cause skin and eye irritations. Keep

that in mind.