There is an inverse relationship in all plants between root congestion and branch/stem extension, such that as root congestion increases, the rate of branch/stem extension decreases. Root congestion also causes fewer leaves and forces anomalous growth that can give plants an easily recognized 'poodle look' because of foliage growth that concentrates near the growing tips of branches (apices). Contrary to what is often popularly believed, no plant prefers to be grown tight.

I would pot up slightly now, gently teasing some of the perimeter roots away from the main mass but not root-pruning, then repot immediately after the blooming phase or early next summer, using a very fast potting medium. Soils like the 5:1:1 mix or gritty mix should be about as close to ideal as you'll be able to get.

See Josh's repotting of one of his plants, for future reference. You should only pot up at this time or wait until after blooming to ensure that the cultural change doesn't cause buds to abort.

Al

Here is a link that might be useful: Repotting tutorial

The only problem with these plants tho is if you move them while theyre developing flower buds theyre likely to abort flowering. I normallly turn mine every now and then but once flower buds form I stop.

Thanks for linking to my Thread, Al, much obliged :-)

Let me also point out that the recent re-potting that I did was "out of season," due to my own
lack of foresight and timing during the primary growing season. For the fastest recovery, the
re-potting is best done, as Al says, early next Summer (or following the bloom, if the situation
is more critical/time-sensitive). Indeed, I noticed that my own plant wasn't as perky or growing
as much as it should be, and I guessed why - congested roots in an old, compacted soil.

My "bonsai" Christmas Cactus is quite root-bound in a smallish container, and yet it grows
like crazy. I think that's due to the fast-draining soil, and frequent water and fertilization.

Lexie, have you been fertilizing your plant?

Larry, you are correct - while the buds are very tiny and beginning to set, it is important to keep
the plant in a fixed position. Once the buds are larger, you should be able to move the plant for
display.

Josh

Thank you everyone for the tips!

Josh-I don't believe I've fertilized, but maybe once mid-summer. I rarely repot anything, even to change the soil so I avoid fertilizing in an effort to minimize salts. City water is bad enough. (Your plant is beautiful, btw. Thank you for the detailed post! I'm sure I'll come back to it when it's time to pot up)

Al-I agree, it probably could use a repot now. Knowing that the poor thing is facing a cross-country move in a month or so, I think I may top off the pot with 1/2" or so fresh soil and wait for a full repot until after the move. I can attest that living things can only handle a certain amount of stress at once!

Besides, I'm clumsy and I'd lose all the buds in repotting regardless of how stressed the plant gets!

I notice in Josh's photos, his plant drapes. I've noticed the same in other photos of Christmas cactuses. Mine is very upright. Is it really a Christmas cactus, or just something related (same leaf shape)?

Lexie, do you have a photo of your plant?

If the margin of the leaf has little points, it is almost assuredly a Thanksgiving Cactus,
Schlumbergera truncata. These do tend to be more upright in habit.

The smaller "bonsai" plant that I have is pruned often, and so the growth is strong enough
to support those branch tips. I like the upright form, which is what I'm trying to achieve.
I do prune the older Christmas Cactus for structure, but I certainly allow more pendulous foliage.

Josh

Lets try doing a photo this way... been a REALLY long time since I've tried this here

Here is a link that might be useful: {{gwi:104768}}