If the trees are in a peat-based planting mix without any fertilizer included, they should begin receiving fertilizer now. One quarter to one third strength should be fine.

Now for the (maybe) bad news: Redbuds are among the most source influenced of all trees in terms of their seed. It's highly unlikely that any raised from FL seed will be hardy enough for upstate NY. If you want to try anyway, they can be planted when they're 1 to 2 feet tall. Redbuds are strongly tap rooted, so deep pots are necessary and getting them into the ground when relatively small is important.

there are a couple types of rebud ... and w/o a proper ID ... it is hard to give any specific info on its future performance ...

second.. trees.. in general .. like a very high draining media in the pot ... and almost any bagged media is going to be too high in peat to favor the tree ... if you are limited to buying media... you should look into a cactus mix ... otherwise .. many peeps here like al's mix.. which is homemade.. perhaps someone has a link to that ...

up here in MI ... Cercis canadensis .. the eastern redbud.. seeds wildly .. onto my wood mulch.. which is on top of mineral sand ... and which is usually about as dry as dry can get ... and i get hundreds of seedlings per year ... with no watering beyond what nature supplies... which leads me to the conclusion that ERedbud.. does not mind being dry ... which i tell you.. so you dont drown them in your pots ...

and if you stop drowning them [not that you are, just meaning excessive watering] .. then you might not need much fertilizer ... but if they are off color.. so be it ...

isnt redbud near native in NY .. the thought that you need to carry it from FL to NY.. cracks me up .. regardless.. live your dream ...

good luck

ken

Here is a link that might be useful: link

Link to latest Al's mix thread.....Container Soils - Water Movement & Retention

I use a decent average grade potting soil for seedlings, and then pot them up into pure Nature's Helper Soil Conditioner (aged pine bark fines) to hold them over until planting out or distribution. I'd use Al's mix if I planned to keep a tree potted long-term, but it's not a "requirement" for short-term use. The cactus mix might be a good idea. I've actually used it once in a pinch, but couldn't really tell much difference (typical store-bought cactus mix isn't all that different from normal potting soil really).

The difference in the two seedlings is very typical. You may also find the the smaller one outgrows the larger one within the first year. Individuals just grow at different rates. I've had scrawny seedlings, that I had considered culling, that turned out to be more robust than the average seedling from the same batch of seeds.

Provenance CAN make a difference in the hardiness of individual specimens within a species. Florida genetics may have issues in upstate NY, but then again, they may be perfectly hardy. You won't really know until you try. If you find they repeatedly suffer winter dieback after several season, you might want to replace them with hardier stock from a more northern region.

Just a side note on Eastern Redbud and its Texas and Mexican cousins. For the commerical plantings we do on government property, these are some of the hardiest surviving trees planted when given minimal to no maintenance. Only Desert Willow does better.

That's where I actually got the seed pods, on my local Extension Office/Master Gardener property. With permission, of course. Thanks for all the wonderful replies. Another question, how and when do I train my seedlings to be trees? I really don't like the shrub version of these I see down here a bit. They look so much better as trees!

You don't have to train a tree to be a tree. There are cultivars that are naturally shrub-like, but a seedling is unlikely to have that tendency. If you did want a shrub form (which you don't), you could encourage that by cutting the leader off just above ground level and allowing the plant to resprout with multiple trunks.

You should watch for proper branch crotch formation. Eastern redbuds probably have the worst branch crotches of any tree except maybe the Bradford pear. Removing branches with the sharpest crotch angles and/or spreading limbs (as you would some fruit trees) are frequently required for good form.

So basically keep the tree compact and cut off branches the same size as the leader and that grow at a sharp angle, right? Should I prune branches off the very bottom over time to encourage upward growth? I know my little 4 inch seedlings are a looong way off from there from there but I have a larger one that's not doing well. That's probably because we followed the nursery's instructions and planted it in the shade. It's not really tree-like but the species is the original Eastern Redbud so its not supposed to be a shrub...

I'm not sure I understand what you mean in that first sentence. I prefer pruning only the branches I want to remove for best form and training crotch angles (when possible), but, if you do use pruning as your primary method to obtain decent crotch angles, you just have to select the branches with the worst angles for removal. You can do the pruning before the branches get large. I would leave as many bottom branches as possible to allow the tree to develop optimal trunk taper and strength, but limiting total branch removal to only the bottom 1/3 of the total tree height is often a good guideline. Trimming the bottom branches may somewhat encourage more height, but, by the time you consider the loss of food resources and the increased tendency for lankiness, the payoff for lower branch removal (as a tool to encourage more growth) is probably not worth it.