Cereus Forbesii is a great choice if you’re after a really spikey cactus that grows tall and fast. However I will add a caveat to the word “fast”.
I’ve purchased a few of these over the last few years as they are readily available from Bunnings from time to time.
The first one I purchased was in a 7cm punnet which I planted into the ground in a nice sunny position. After about a year though it hadn’t really done much at all so I dug it out and replanted it in a pot. Over time I purchased a few others as I really liked the blue/green colour and they were relatively cheap to buy. However I never really had much success getting them to grow.
One weekend though I came across 2 in Bunnings in 10cm punnets. One went into the ground and the other got potted up into a larger clay pot. Anyway the one in the ground really took off while the one in the pot didn’t really thrive at all. No surprise!
Here are the photos of the one in the ground.
13/04/2020
So you can see, in about 3 years it grew to about 2m tall. Out of the 6 or 7 of these I’ve grown over the last few years it really was the only one I’d had any real success with. So considering that all of these were seed grown the question was, whether this seedling was vastly superior to the others or was it just the situation it was planted in. Over the 3 years I can’t remember watering it at all or giving it any fertiliser. However it did have a free root run and there was a compost bin right next to it leaching nutrients into to ground below.
Therefore, being curious, the next step was to take some cuttings, root them and then plant them into a less favourable situation to compare the growth rate.
Therefore I took 2 large cuttings. Each about a 1/3 of the overall height.
Using Cereus Forbesii for grafting stock.
Cereus Forbesii has a couple of really good qualities that could potentially make a it a great grafting stock. Firstly, this one is quite vigorous. Secondly, unlike alot or Cereus it doesn’t have deep ribs. It has a large epidermis and a large flat area of cross section to attach a larger diameter scion.
Potentially on the negative side, from my experience, it doesn’t seem to perform very well in pots (unlike Trichocereus). Therefore I have a couple of options. Once the mid has rooted, I can cut it in half, use the bottom half as a root stock and then re-root the top piece. Alternatively, I could just let it pup in spring and then use the pups (still attached) as root stock. We’ll see!!!
The other option is to use the plant still in the ground as a root stock.
The second Cereus Forbesii, which I had some success with.
I’m pretty sure I purchased this one a few years previously in a 7cm punnet. There were 2 together. It then got potted into a 15cm clay pot. Over the next few years it didn’t put on any growth at all. Then at the start of 2022 it suddenly started to grow. So in the ground it went.
It then continued to grow quite happily until mid summer 2023. Then this happened!
Here’s what happened! The evening before the garden was getting a water as the next day was forecast in the mid 30’s. I’m guessing, but not certain, that this one got a nice drenching. It uploaded quite a bit of water, got top heavy and then just fell over. It can happen!!!
I then left it for a few days to see if it would right itself. But of course it didn’t. Therefore the horizontal piece got turned into a cutting and the remaining then got dug up, separated and then banished into 2 plastic pots.
Here’s the outcome.
And here’s the cutting after being potted up for a few months.
FOOTNOTE:
Here is one of the other Cereus Forbesii’s which I haven’t had much success with.
Conclusion
Most gardeners know it’s normal for seedlings in the same batch to have at least some variation in vigour, hardiness etc. With the Cereus Forbesii from Bunnings there seems to be quite a bit of variation. From experience this doesn’t appear to be unique to just this cactus. Over the last few years there have been quite few Pilosocereus Fulvilanatus seedlings available. I really like this cactus. So I over time I’ve purchased about 7 or 8 of them. I’ve noticed a difference in these as well. Some are hardier and more vigourous than others.
So, what is the message here?
Often gardeners see a plant they like, buy it, plant it and sometimes it dies. The opinion is then that the plant wasn’t any good or not suited to the conditions. However, if you really like the plant buy a few more and give them a go. You might just find one that is much better than the rest.
PS. If you’re used to giving your Trichos a good water during the summer, then try and resist with Cereus Forbesii or maybe just be a bit more frugal. In the ground they don’t really seem to need it!
PPS. This upcoming spring and summer I’ll be keen to see how these large cuttings go and how suitable Cereus Forbesii is as a grafting stock. So I’ll likely update in 2024.