Pencil Cactus Pruning: Pruning My Large Euphorbia Tirucalli

As many of you know, I recently bought a house and moved. My (once) 8′ Pencil Cactus was the only plant that really took a hit in the moving process. I needed to get the Felcos out and spring into action!

Buying, selling, and moving are always a process, but the volume of indoor and outdoor plants I have made it even more of a challenge.

The movers did a great job handling them all but the Pencil Cactus, like some other succulents, breaks at the drop of a hat. It wasn’t able to stand up on its own and is really heavy so I’m happy it came out of the moving process so well.

I live in Tucson, Arizona where this Pencil Cactus grows outdoors year-round. They make wonderful indoor plants if you have medium to high light and I also have a smaller one growing indoors.

This pruning adventure yielded quite a few cuttings both large and small so once they get potted up, I’ll soon have another plant plus quite a few to give away.

The Pencil Cactus pruning in action:

Reasons to Prune a Pencil Cactus

1. A Pencil Cactus grows fast & tends to get top-heavy over time. This 1 of mine was propped up in a corner of the house. Pruning off a portion of the top has helped it to stand up on its own.
2. It’s getting leggy. This is usually due to a lack of light.
3. The plant has grown too tall or is getting too wide. This might cause your Pencil Cactus to lean.
4. You want to propagate the plant via cuttings.

My PC plant that grows indoors. I planted it from cuttings taken from the large plant late last spring. I brought a couple of cuttings from my large Pencil Cactus in Santa Barbara when I moved to Tucson 4 1/2 years ago & that’s where this large one came from. These plants propagate so easily!

Important things to Know About Pencil Cactus Pruning

1. Before you start the pruning process, be sure to clean & sharpen your pruners. This will ensure that you make clean cuts.
2. Warning: A Pencil Cactus, like other Euphorbias, will emit a sap when cut into. This milky substance is considered to be toxic. I’ve gotten it on my skin & it has never irritated me but it may be different for you.
3. I would advise wearing long sleeves & gloves when pruning this plant. Not only will this protect your skin, but the sap can stain your clothing. And, never get it anywhere on your face.
4. I cut up rags into smallish pieces to help contain the “sap flow”. This helps to keep it off of you, the plant & the surroundings. It takes about 5 minutes or so for the sap to stop dripping, depending on the size of the branch. 
5. Make the cuts straight across, just above an existing branch or branches.

Best Time of Year for Pencil Cactus Pruning

This is a do as I say, not as I do! Spring and summer are the best times to prune a Euphorbia tirucalli. I’m in a climate with a warmer fall and winter so late winter and early fall would also be fine.

I pruned mine in early January because the very top branch (40″ in length) had snapped in the move. The plant was leaning against the house and the patio fence so I wanted to get it shaped up as soon as possible.

Pencil Cacti are hardy to around 25F. Mine grows outdoors year-round. We haven’t had a freeze night or 2 yet this year but some evenings have dipped to around 34 – 36F.

After I pruned, I covered it with a sheet as protection while it’s healing and will leave it on for a week or 2.

How I Pruned my Pencil Cactus

1. Clean & sharpen pruners.
2. Cut up the rags.
3. Remove the large broken branch.
4. Prune 3 additional larger branches. 1 was tied to the mini-clothesline, the other was completely bending over, & the third was the other top branch. 
5. Stand back & see how it looks.
6. Prune a few smaller branches towards the back to get them off the wall.
7. Success – the plant now stands on its own & looks better!

The Cuttings

I always let my Pencil Cactus cuttings heal off (dry over at the ends, like we do with a wound) for quite a period of time before planting.

Some succulents cuttings will show roots and some won’t – no worries, just plant them and the roots will form. The latter is true of a Pencil Cactus.

It’s now been over a week since I’ve done the pruning. The cuttings I took off this plant have healed off and are laying on the floor of my guest room. They get moderate light but no direct sunlight.

I could plant them now but I’m going to wait until the beginning of March to do it. By the way, I’ve found that the larger stems do as well as the smaller stems when planted.

With those 4 larger stems, I’ll have 4 Euphorbia tircallis well on their way!

I’ll do a post and video on propagating and planting these Pencil Cactus cuttings so stay tuned for that.

What Happens Next?

Whether the Pencil Cactus remains in this spot or not remains to be seen. It gives a nice hit of greenery right off the patio, so it most likely will stay right there. 

I’ll assess how it’s growing and see how it looks in early May.

I may need to do a tip pruning (in case you don’t know, this is the removal of the soft new growth by 1-6″) just to do a little further shaping.

Conclusion: Pencil Cactus grow fast and are forgiving when it comes to pruning. You can prune them lightly or heavier as I did. Just mind the sticky sap and give your pruners a good cleaning before and after pruning. They’re easy to grow and are a fun plant to have in your collection!

Happy gardening,

Nell