Well, first things first: it's a Dracaena fragrans. I think. The reason why it hasn't attempted to grow back any of the lost leaves is because it can't. All you can do when you're a Dracaena is get taller or branch, and branching would only be likely if it had grown mostly horizontally for a period of time, or if it had flowered. So it gets taller. Is there a way to regrow? Well, kinda. You could cut the plant back, at which point it would be forced to sprout new growing tips. Or you could air-layer (.pdf file) and start over again with the tops of the plants. The more interesting question to me is why you're losing so many leaves in the first place. Granted, keeping your plant alive for two years is an accomplishment in and of itself, but the leaf drop looks like a fairly extreme case of something or another, too. It would like more light, though that's not why it would be dropping leaves. Soil breakdown is a possibility, as is over- or under-watering, fertilizer buildup, and temperature. Pests are an outside possibility, but these aren't really known for having pest problems, and most pest problems would have progressed well beyond obvious by now. So. When you water, do you pour water in until it starts running back out, or do you only add a little bit at a time? Does the plant ever have to stand in a saucer full of water? Is the plant in a draft? Is the plant in the path of an air conditioning or heating vent? How long has it been since the plant got new soil? Is the water in your area naturally high in fluoride? How do you decide when it's time to water? (by schedule? by feeling the top couple inches of soil? by weight of the pot? whenever you remember?) Are there roots coming out of the bottom of the pot? I'm going to go ahead and bet $10 on soil compaction and/or rootbound: that's a lot of plant for the size of the pot it's in. Unlike saucer, I think I would go up a pot size unless you're planning to cut it back, and if it's as potbound as I suspect it is, I might move it up to the next largest size regardless. If it were my plant. Which it is not. Look at the roots first, like saucer said.

i was looking at my saucer just the other day .... in my z5 .. i realize you are a bit warmer zone.. but your plant should not have been on the verge of blooming.. i suspect ... on mine the buds were just losing their winter covering.. perhaps as big as my index fingernail ... if your buds were any more extended.. there is a chance the plants came from a warmer zone.. and where further along in bud break.. and they got exposed to cold.. somewhere on their trip to your garden .... a hard frost or freeze can damage buds .... and yet the damage will not 'show' for a few weeks.. so blame someone else.. lol ... though disease is an POSSIBLE issue ... i would look at problems in this order: digging damage from the grower if bare rooted this spring shipping damage hardening off to your zone transplant shock etc long before i would consider disease .... give it a month or two.. to see if it leafs out ... if so.. you are all set .. frankly.. i never expect much more than the plant living the first year.. the flower show will come in a year or two ... when dealing with conifers/shrubs/trees ... there really isnt instant gratification.. they can live for hundreds of years.. so if we have to wait or year or two... it should NOT be a big deal ... but for our own expectations ... in a perfect world.. you should have planted the plant while fully dormant.. the fact that it was growing.. puts you a bit behind the 8 ball.. and perhaps you are seeing the effect .... i doubt it will die .... just delay the flower show ... unless it is diseased.. lol ... good luck ken

At the risk of sounding rude (which I hope I don't in questioning this), I'd just ask, are you sure it was cold enough inside your school for parts of the plant to freeze? If so, brrrrrrrr. If temperatures drop under 40 degrees, I don't keep my jades outside at that point, and jades certainly are not frost tolerant, but I would be surprised if your inside temperatures have dropped below 40? But maybe they have right next to a very old window during the winter. I only question it because other factors could cause parts of the plant to die off, and the plant may not have been at optimum health to begin with, based on it being indoors and not having big, healthy roots. It sounds to me, based on details such as your saying the root system is small, that the plant is probably not in well-draining soil and that it's possibly not receiving enough light (they don't thrive as indoor plants). Parts of the plant dying back and leaf loss are indicative of a situation where the roots are unhealthy (confirmed by a small root system), and rot could happen as the roots continue to die off. And no, there won't be a stench with the rot. If the root system is small, that's perhaps the biggest indicator that the soil is too heavy. If it's in bagged soil, even so-called "cactus soil" from a store or nursery, that won't be well-draining enough. You'd want to mix well-draining ingredients like pumice or perlite into that soil to lighten it. Also, it's important not to overwater. I wait until the leaves have a very slight give to them--the plant will actually tell you when it wants water. You don't want to wait until the leaves are wrinkled or anything close to, but you can learn to feel the leaves and discern if they are barely less plump than they are normally, and at that point I water and the leaves plump up again. And again, in the wrong soil the plant will retain way too much moisture for too long, so that'd be the first issue to look into. This post was edited by teatree on Fri, Jun 28, 13 at 20:27

Miracle grow potting soil actually is not much more than a bag of peat moss. If regular potting soils are used they have be admended with wood chips, CHC, cedar chips, pine bark or other coarse material to help increas the draining and root zone aeration. I know growers that have used Maricle Grow's Garden Soil with success, still I would recomend adding coarse material to that. . If you pull your trees out I'm sure you will find that your tree's root system are in real trouble. With all the water that Miracle Grow Potting Mix holds, the trees's roots must be starved for oxygen. -S-