Yellowing Agave Americana

[guyhamilton]

Agave Americana

Hi,

I live in the southern UK in Chichester and have a large but poorly Agave Americana (see pictures below) that has up to a few weeks ago appeared very healthy (no yellowing).

I have brought him inside for the winter months and noticed his soil wasn’t draining very well and there are a number of woodlice present. So I drilled 15 or so 10mm drainage holes in the bottom of the pot to improve drainage whilst I waited for spring to repot him with new soil. The unintended consequence is that I have damaged the root system when making the holes and I think I have local root rot (I have been kicking myself). The plant began to yellow its leaves (predominantly the bottom ones) and the photo below is about 2 weeks after making the holes. The yellowing has slowed recently. The soil all though much less water logged is still not draining as well as it needs to.

What I would like some advice on is where I should go from here. I though of the following options;

1. Remove my Agave from his pot, wash off the soil, tend to the localised root rot (I am not sure how to stem this). Allow to recover. Repot him and his offspring in new cactus soil in new pots. Water after a week (or longer/shorter) to prevent repotting root rot.

2. Leave the Agave to recover and stop all water. Repot him in spring.

3. Any other options / advice?

[greenknight]

I'd go with option #1. As a general rule, if you have any reason to suspect root rot you should take the plant out of its pot and inspect the roots. The can recover from any damage that might do to the roots, but if rot spreads too far it's dead. The sooner you cut off any rot, the better. Cut anything that's rotten well clear of any discoloration.

I would wait much more than a week before watering. During the growing season I would wait a couple weeks, In Winter I'd wait until Spring to water it. Don't remove any leaves that haven't completely shriveled, the plant will continue to pull moisture out of them to sustain itself. That's what was happening - the roots were failing, so the plant was consuming its lower leaves.

[BarryRice]

This is a tough as nails plant. I wouldn't worry about the damage to the root system--but if you think rot is a possibility, take it out of the soil, let the roots dry out for a week, trim off dead roots, then replant in a dry medium.

[guyhamilton]

Thank you for your replies - I am going to bite the bullet and go with option 1 - the soil is also now 3-4 years old and the drainage is not as good as it needs to be (hence woodlice!) . Interesting to hear the reasons for the yellowing leaves confirmed. I just hope I don't lose too much blood in the re-potting process .

Guy

[guyhamilton]

Hi,
having now depotted the aforementioned agave I found the soil to be pretty damp. I have removed as much soil as I could without really breaking up the root ball and removed the pups for repotting.

Should I continue to break up the root ball (see below) or will this cause unnecessary stress? The soil is pretty old and it hasn't been drained well for a while so I doubt its very porous anymore.

At the moment I am letting him dry out and his pups will be repotted shortly.

Thanks to everyone that s offered advice this far - repotting a large agave is not for the faint hearted!



Guy

[greenknight]

Don't worry about the stress. you need to get rid of that bad soil. Best to remove it while it's damp, less root breakage.

[K.W.]

Good evening Guy,

the agave now lives in your home?
Do You have many apples in the room, fruit bowl?
Apples emit ethylene.
Agaves not tolerate ethylene. Then show exactly the symptoms of your plant.
The leaves turn yellow / brown and dry up. It also often leads to rot.

Best wishes

K.W.

[guyhamilton]

That's very interesting - I don't have a fruit bowl but I do eat quite a few apples and drink apple juice which would be more potent. I will drink the rest of the apple juice and apples in a separate room and not buy / eat anymore whilst I have the plant at home. Where did you find out about that issue? Thank you for the information its not something I had considered.

Grub

Guy

[guyhamilton]

Having looked into the issue a bit - ethylene is given off by climacteric fruits (which include apples) but is also a plant hormone which encourages leave shedding.

Guy

[HP22B]

You absolutely don't have to stop drinking apple juice for your plant's sake... I would only see ethylene gas being a problem if you kept multiple apples or bananas under your plant at all times. By no means do you need to clear them from your house.

[BarryRice]

Take your plant outside, turn the hose on the root mass and wash away that nasty soil. Start afresh with something that drains well.

[guyhamilton]

HP22B - your right, an over reaction on my part. I am going to get the soil out repot him in fresh and ignore him for a while.

Guy

[guyhamilton]

Hi,

I have completely cleaned the soil off. I have trimmed back any rotten roots, however I have found one or two that were rotten to the point of the plant. Is it sufficient to thoroughly dry the root ball and let the plant repair any damage and then re pot or do I have to keep hacking back until I find healthy plant tissue.

Thanks

Guy