35+ year old cactus turning yellow

Question

Hello fellow plant lovers!

I've adopted this beautiful 35+ year old cactus from a friend moving across the country, however I'm concerned with the yellowing you see here in the pictures. The yellowing is not all over the plant, there is some green on some sides, but there is more yellow than green. The cactus is still firm to touch and not mushy.

When I picked up the cactus it was leaning on the pot pictured. My friend and I repotted it for transport. The roots were very dry, though they seemed healthy. We removed roots to encourage root growth, I can post another picture of its roots when I repot it later this week, as this pot is far too large for the root system.

My friend mentioned the yellowing started whenever he moved it from a less sunny spot. He also mentioned he did not water the cactus often.

I'm fairly experienced with succulents, however not so much with mature cacti. I believe it is a watering problem - the combination of the cactus being in too large of a pot, as well as possibly not receiving enough water, and even enough sun. At the moment, the cactus is in a west facing window where it will receive 5-6 of direct sun, and plenty of bright light in the morning. There's also an option to move the cactus outside during the summer when it's nice and warm here in Canada.

I'm hoping someone more experienced can give me some insight on what the problem may be, what the chances of survival are, as well as give me some recommendations on how I may salvage this beautiful cactus. Also, if you happen to know the name of this cactus that would be very helpful as well!

Thanks in advance :)

Bex

Answer 1

I hate to be the pessimistic bringer of bad news, but I think your cactus is either dead or mostly dead.

It's an Echinocactus grusonii, commonly a Golden Barrel. As cactus go, this one is fairly robust and easy to care for.

The discolored part of the plant looks like rot to me, unfortunately.

You could get some anti-fungal (sulfur or something like it) from your local garden section. Keep it dry and keep an eye on the top center of the plant to see if it's making new spines. That's a sign of growth.

It's unfortunate, because the spine growth on top looks very good.

I noted that you are in Canada, is it possible it was near a window and got frost damaged? The bad part seems to be on one side, for the most part.

The good news is these things are all over as a common landscape plant here in Arizona, and I've seen them half rotted away and heal and keep growing. So, you never know.

If it were me, I'd leave it as is, water it when it gets really dry, avoid getting water on the skin (don't top water). Pour gently around the base of the plant. Give it half to 1/4 strength balanced fertilizer occasionally, it seems to be growing.

Good luck!