Caring for a potted citron tree

March 7, 2011 12:48 AM

I have long-term custody of a potted citron tree that's a year or two old. It seems to be doing OK, but the central stem/trunk doesn't have any leaves at the top of it: Photo of the tree here. Should I prune the top of the trunk? If so, when and how? Is there any other pruning I should be doing at this point in its growth?
posted by rivenwanderer to Home & Garden (7 answers total)

Best answer: Based on my own limited experience* of citrus trees, you can cut it down rather harshly. I usually do my pruning when the tree is in growth - ie it puts on new leaves.

Try to get the cut as close to an existing branch as possible (to avoid dead stumps on the stem).

A question: During the years, have you repotted the tree? It can work wonders

I try to put a new top-layer with rich compost in the pot or repot the whole plant every other year. When I repot, I use good quality earth mixed up with coarse sand to help drainage.

* I have a couple of potted citrus-trees that put on flowers and fruit in a hot-house. But rest assured that I have killed a couple of trees also. Possibly by watering them too much during their dormatory period.
posted by Rabarberofficer at 2:27 AM on March 7, 2011 [1 favorite]

I can't tell from the silhouette if the top is dead or not. You can usually tell if it is by the tissue distinctly changing color or looking dessicated. You can scratch a small portion of the twig with your fingernail and if it's not bright green under the surface it's prolly dead there and you can cut it, just before it changes back to live tissue. Unless it's spreading down in which case you should cut it further in where you don't see any discoloration. Because the tip could have died from something like underwatering for a critical time, in which case the dieback shouldn't spread, or it could be from a fungal problem which could be active. In general you don't want to cut into the live tissue because the plant has already walled off the injury.
You asked about pruning- you don't necessarily need to prune it. What's your plan for this tree? What size do you want it to be? If you're going to keep it indoors in a pot you'll have to start pruning at some point, basically to bonsai it, keeping the growth reined in by pruning the crown and roots occasionally. Don't indiscriminately hack at it, because removing foliage= removing food.
I wish I had time to write more…
posted by Red Loop at 3:14 AM on March 7, 2011

If you want some side growth out of that central stem as it is, prune it just above a growing point, which I think are the spikes you see on the stem. (If it's like my limes... but google a bit to be sure?) Then if the plant has enough nutrition those should form leaves and eventually branches. Over time you can pick a few branches to be the biggest that form the skeleton of the tree and determine its overall shape. But if you think that the stem is still growing vertically and you want more height, leave it. Don't be afraid to prune trees like this but you don't have a ton of leaves on there right now so I wouldn't take more than a few off at this time. Can you take another photo of the top of that central stem, away from the window so we see it without the back light?
posted by thefool at 7:42 AM on March 7, 2011

Also, are you fertilizing it? Citrus are heavy feeders.
posted by cyndigo at 8:45 AM on March 7, 2011

Response by poster: I believe that the top couple of inches are dead; underwatering may well be the culprit. I'll probably cut the dead part off the top and do no other pruning for now. I'll also re-pot it (since it's in normal potting soil right now and I've read that citrus needs more drainage) and start a fertilizing regimen.

Can I prune the top and re-pot at roughly the same time, or should I wait for the plant to recover from one before doing the other? What order should I do them in?
posted by rivenwanderer at 10:08 AM on March 7, 2011

I'd do them both at the same time, under the "get it over with" theory. Plus if you just cut the top dead part, that should not be a huge shock. Do not under any circumstances let the plant view 127 Hours, though.
posted by cyndigo at 2:17 PM on March 7, 2011

I'm with cyndigo here: Do all the damage at one time, then leave the tree to deal with recovery while you nurse it with water and sunshine.

A personal note, when I repot citrus, I don't immediatelly start to give it fertilizer. Usually I let the tree establish new roots for a couple of weeks (a month or so) before I start to give liquid fertilizer.
posted by Rabarberofficer at 10:20 PM on March 7, 2011 [1 favorite]