I would think that just changing its environment light wise could have shocked it enough to prevent flowering, and there is a good chance it's not getting enough light where it is.

Since it's not in a good place re: flowering right now, anyway, I would recommend that you wait until Fall when the new growth stops emerging and the plant has slowed down in general then carefully re pot.

If it were me, I'd wait until the plant was out of the pot to decide what to re pot into. It may not be reasonable to separate the babies from the larger plants without destroying their roots, and if that's the case you'll repot the whole thing to a larger pot. But, if you can separate, then that is the best option, in my opinion.

I like terra cotta pots because they tend to wick the moisture away from the soil (vs. a plastic or fiberglass pot) and Clivia do not like wet feet.

Regarding mix, you have to think about what Clivia like, so not a dense mix, but a mix intended to allow the moisture to do its job and then dry out. I pot mine in a miracle grow product intended for cactus and succulents mixed with a small amount of regular old potting mix and it seems to work well for me.

Best of luck with your Clivia and my condolences on the loss of your Aunt.

Unfortunately, the only way to separate the offsets from the mother plant is with a knife. They are connected at their base and healthy clivias have a lot of ropey roots. They look a lttle like orchid roots, but they are much more brittle. Even experienced clivia growers lose roots when they transplant. But, mature clivias like yours are also tough, and the plants will be much healthier in the long run if you separate the larger offsets from the main plant. You don't have to seperate all of them individually at once. You could just cut tlhem into three or four clumps. Just make sure that each clump has a lot of roots. Also, in my experience the best time to transplant is now in the northern hemisphere. The plants are in their growing stage. In the fall they will be ready to go dormant.

I agree that you need a fast draining mix. You can use cactus mix or even orchid mix. The other thing that helps with flowering is regular fertilizizing with a complete fertilizer with micronutrients.I feed my clivias at least once a week from january hrough September.

Thanks for the great advice! I am definitely going to repot and move to an area that gets just a little morning sun and no afternoon sun. It's so hot down here in the summer, that I'm afraid that after being in shade so long, it will get burned if I move it. I'll try to acclimate it a little at a time.
I have some orchid mix that has small pieces and some that has large pieces. I don't have cactus soil, but I can get some. Should I mix the cactus soil with the orchid mix to add some organic matter?

I'm sure it is very rootbound after so many years in the same pot, so I may not want to separate it. I'll see when I get it out of the pot. I'll take a picture and post it to see what you think.

Believe it or not, my aunt grew this from a tiny piece that was tossed out on the side of the road when someone repotted theirs. It only had half a leaf and one root when she got it. I was just reading her garden journal. That was in 2002. She put it in this pot, and never repotted it. It's amazing that it is so healthy.

Thanks for the condolences. She was a special lady who taught me a lot about gardening. I inherited all of her plants, and while some I gave away because I had duplicates (started from hers, actually), the clivia is one I'm keeping, along with some brugs and a gorgeous desert rose she grew from seed. I hope I can do them justice.

Some of my most cherished plants were inherited or gifted from my mother and grandmother. Its a connection to the web of life that I truly value.

On the potting soil for your clivias: I think the best course would be to combine two parts of the smaller bark with one part cactus mix. Clivias don't like organic material other than bark (like manure, peat or compost). They really do much better in a fast draining mix of inert materials. One reason people say they like to be potbound is that when they are, water rushes through the pot. Soggy soil will kill the roots.

The story about how your aunt started the plant is one I've heard before. I have even seen a clivia that was unpotted and forgotten on the floor of a greenhouse for several months that bloomed. They do benefit from regular, full strength fertilizing; drying out between waterings; and bright light. I have mine in dappled sunlight. The leaves will burn if they get full sun between 10 a.m. and 4 p.m. though.