Each stem has a certain amount of leaves right from the beginning---it will *not* get more leaves or branch with time. As your plant matures, the stalks that emerge will be taller with a larger number of leaves on them. They'll grow quickly to their final height and will not grow taller. :)

Thanks shiver :). That's just what I wanted to know, and I couldn't find the information anywhere, so am glad to get it from here!

(My first thought when I saw the subject line was, "agonizingly slowly.")

LOL, mr_subjunctive! This plant has been agony from the start. When I got it, it was in pure, hard sand, in a pot with no drainage holes, and it was the first time I've ever tried repotting something because of bad conditions. I had no idea what I was doing, and am still fretting over it as though it's the most precious thing in my life. Just cannot believe that I would get like this over a plant! I even thought of tossing it, and buying a new one that was appropriately potted, but felt guilty about being 'disloyal' to this one. It seems fine so far, so here's hoping.

These are quite sturdy & rugged plants, you could relax a bit. I think it's pretty hard to kill them except by overwatering. I've got 2 or 4 of these at home, several of which I grew from single leaves. Agonizingly slow, but very nice.

BTW, in my experience, this is their most active time to grow, Septemberish mine usually throws a new stem or 2 at least.

Thanks, pirate_girl. Yes, I think I do need to relax a bit. I'm slightly anxious about all my plants, because although in London it's quite warm, we've had an unusually overcast summer, so there's been a noticable lack of sunlight.

Good to know that this is the growing time for ZZ plants, though -- thought I might have to wait until next year to see anything. Just hope that the lack of sunlight hasn't been a huge problem. My jade seems to be growing well (although, unusually more, for this time of year, and I was wondering if that was because it thinks summer's over -- I've found that my jade prefers to grow in the winter); but I've no experience with ZZ plants, so had no idea what to look for.

Londongirl,
Have no fear about not enough sunlight for your ZZ. As Pirate Girl said, they are very rugged plants, and can tolerate much lower light conditions than many plants (mine is quite happy getting about as much light as a snake plant), but will grow faster if given more. If your jade plants do fine, this will, too. The only threat is overwatering. Only water (and then soak throroughly) when the soil is bone dry all the way through.

BTW, isn't it always overcast in London? ;P