Monday, 8 August 2011

Red means danger

I have commented before that the colour of aloes and echeverias can be altered by controlling the amount of sun and water. Plants like echeveria 'Big Red' need lots of sun to go a good red colour.

While others like aloe purple flush need to be kept overly dry to get the best colour.

Either way colour is something we try to induce in some succulents. Today I was reminded that sometimes colour in succulents is not good and can be a warning of something not being right with the plant.

One of my favourite agaves is a. filfera x isthmensis.  It is a lovely little cross and has grown well since I got it a couple of years back.  Normally it lives on the windowsill in my shed (my substitute green house), this year though it has been outside with the rest of the agaves.

I had noticed that at some point it had gone red, and given that many plants do this when you move them out into the sun for the first time I did not think much about it at the time.  Looking around this weekend it was still red which I thought was a little strange, although the latest leaves were going back to green. I posted this on a forum and was reminded that red leaves in agaves is often a sign of root damage.  So today I took it out of the pot to have a look and sure enough the majority of the roots were dead with only 2 or 3 new healthy roots. As there was no sign or rot, the roots were cleaned up and the plant repotted and moved back into the shed and a bit less sun. The good thing is that the new roots are healthy and the new leaves seem to be growing fine, so no long term damage.  It is reminder of the signs succulents can give that everything is not well.

I had heard about the colour issue before; in relation to offsets.  If you take an offset of an agave and it has minimal or no roots, one of the worst things you can do is to put it in the sun.  They should be in a nice shady spot while they develop their roots and ability to take in water.  Too much sun will turn the plant red in the same way, warning you that it needs to be moved.

It is far better to catch a problem early than to have to nurse the plant back to health once things have got much worse. With problems with the roots, they are difficult to spot, unless you happen to be repotting the plant anyway. So watching out for changes in colour in agaves, is a good one to remember.


  1. I had no idea, thanks for the tip!

  2. Interesting. I've never seen that.

    I love the Echeveria. They have the most amazing colors.

  3. HB: E. big red is a really good plant, it would go really red for you. Well worth a space.