The most likely situation is that the tree is juvenile. Citrus trees don't mature with age; rather, they mature with height (specifically, number of nodes -- the bumps onto which leaves are attached, away from the original seed point). So, when the seed sprouts, the first little pair of leaves are at node 1. The next true leaf is at node 2, etc. The tree is genetically preprogrammed to mature at some high-number node -- lets guess 1742 (don't count that number as at all correct; I just picked a big number out of the blue). Indoors, most people do as you've done -- they cut it back when it gets too tall. And there's the problem -- if it had reached node 1740 at its original height, it could have bloomed on the next growth flush. But you pruned it back to, say, node 400. Now when it grows again, it starts countting 401, 402, etc. It will be a while to get back to 1742. As long as you keep pruning it, it will never flower.

To fix the problem, without adding another story to your house, I'd recommend air layering an upper branch. When it is well rooted, harvest it and pot it up as a new plant. Once you're sure it is going to survive and thrive, throw the old original, big plant away. The air layer, taken from the top of the tree, will "remember" its high node numbers, and continue counting from there. So in that plant, rather than the ground-level node being 1, it may be 500. You have a big head start!

Other things that would lessen flowering indoors -- lack of light is the major one. Citrus trees like all-day sun, and anything less may be tolerable, but it won't be appreciated.

Good luck.

Malcolm

Hmm... alright... I might do that the next time they decide to trim it. Where would I find information on this technique?

-Kat

Graft buds of fruiting trees onto your tree. Play it some Dylan. Say nice things to it. Hope this helps! Scott

this web site (actually a PDF file download) explains air layering.

Here is a link that might be useful: air layering document

Midnight, I'm sure MM's advise will help, but for the time being, ask yourself these questions..Has the tree ever been fertilized? When pruning, are you cutting off fruit stems? Is the tree ever brought outdoors? Is it getting proper sunlight?

Two stories? How high are we talking about? Sounds gigantic..lol..Toni

Never been fertilized... no idea what a fruit stem looks like... and no, it's never brought outdoors... It spent a good 5 years in a south-facing sunroom with bay windows.

And yes, two stories... like close to 18 feet tall. My parents finally trimmed it so it wouldn't fall over, and it's back to one story (9') tall now.

I wonder if it's for the same reason Crassula (Jade plant) won't bloom if it's grown indoors? They seem to need fresh air, temperature changes etc to flower.

Cheers, Barrie.

Sounds like great digs, And bay windows sound like enough light... Id vote for fertilizing it. I repotted in ligher soil, fertlized a few times this summer, and my 2 yr with me (oribab 3 yr old) Nana pomegranage had way more blooms than ever, and has kept about 10 fruit. Im excited.

good luck, Ive read not to fert going into winter because the new growth wont do as well in the low sun...

I agree w/NOT fertilizing in winter. One more dose would be sufficient, but I wouldn't feed again until new growth and longer days are once again here. Toni

I would fertilize during the winter, at a reduced dosage. - Millet

I really should do the math and figure out the ppm for my fertilizer. Or, is there an easier way, like half strength for winter?

Weve got flourescents for a few hours in the evening, and almost all the tender plants indoors (citrus, some herbs, a tomato). its kinda cherry. I forgot how nice it is to have houseplants (the cats have only gotten sprayed with water once for messing with them)

Garn, pick up a citrus book and read what they say about winter feeding in colder climates. Or any tropical plants for that matter.
If you've say 2 months of warmth and sun there in Tn, then I'd continue feeding, but if days are cooler/cold and sky grey, then I'd think about feeding.
If anything, reducing food by half dossage is better than feeding full strength. It's common sense. Use your judgement. Toni

Has anyone tried the breeder's trick with citruse from seeds?

Well the trick is to graft a budwood from a seedling tree unto an old fruiting compatible citrus cultivar. This will shave off significant number of years of waiting for a citrus seedling to fruit.

And yes, this trick is the other way around and has worked very well for pome and stone fruits. In order to save time to know the type of fruit a newly hybridized seed will have, instead of growing it and waiting for it to fruit, they graft it unto fruiting trees of the same type. The resulting interaction has been proven to significantly reduce the number of years of wait time for a new hybdridized seedling to bear fruit. I was wondering if this could be true for citrus.

In the specific case of the grocery grapefruit, most likely it would be nucellar and so is the exact clone of the parent, so why not use the budwood from the original parent and graft unto the seedling instead? However, if the seedling is suspected to be a hybrid, for sure it will have different character and particular mix of the parents, and now that it is twenty years old, grafting buds from this tree unto a fruiting grapefruit should shorten the wait time, but the probability that it is a hybrid is not on the good side.

However for those who have been hybridizing citruses and wanting to know the type of resulting fruit you have, you might do the trick of grafting the seedling unto a fruiting mature tree.

Joe, any idea how much time grafting a seedling bud onto a mature fruting tree would save? I have about 150 hybridized seedlings of clementine. Have you actually tried it? - Millet

Not yet on the citrus. But if given a hybridized seedling I will surely do it, but I have none and usually not allowed to import seedlings from out of state.

I have only tried this on wild plum which I hybridized. The seedling bloomed after 1 year on the old tree but the fruits got aborted, maybe this year, I will know for sure. With the pome and stones, the time to fruit is cut in half. So perhaps you can try with citruses, those that have harvestable budwood, would be interesting to try as basically you will only have a few cut branches as a set back, which means minimal risk but many potential gains on the endeavor. Have fun!

Joe, with a 150 hybridized Clementine seedlings I would not worry about any risk. I, of course have the mature tree to receive the bud. I will try it this weekend, on several trees. As the trees are growing in a greenhouse, the wood is always slipping. Thanks, Joe, for the tip. If Dr. Manners happens to read your thread, I wish he would give his thoughts. I'm going to have to get to Davis sometime and tour your yard. BTW, I realize that Clementine's do not come true from seed, except for the few nucellar seedling that I get, which I never keep. - Millet

That's great. You are always welcome to drop by, although my yard is tiny and not that great, perhaps you have a bigger greenhouse than my yard.

Thinking about this grafting interaction, it could work both ways. When you graft a scionwood from a mature tree unto a seedling, the fruiting is delayed, but overall a lot faster than from a seedling. So if you graft a seedling budwood unto a mature tree, it should inherit some maturing chemicals to the younger scionwood and speed up its maturity for fruiting. The only proven one that I come across several scientific journals are those of the pome (apples, pears, quinces) and stones (plums, peaches, nectarines, cherries, pluots). I haven't come across citruses, so it would be a great contribution if you write an article about your results. Even if the results may not be significant, it would still be a great contribution.

So I realize this is an unbelievable necro but this still popped up first on my google search when I was looking for information on this subject, and I wanted to add that I recently purchased a small (~5' which I then pruned to 4') grapefruit recently, and upon placing it under a 400W HPS on a 24 hour light cycle, it developed blooms within about 2 weeks.

So either this grapefruit was shocked into blooming by the ridiculous life cycle it's had (nursery -> Home Depot lighting -> 24 hour light) and is currently in peril, or grapefruit bloom during a very long day cycle.