| Lots of questions so lets see what we have.
Your purchasing plants from the clearance at big box stores means the plants are more damaged then you think. These stores seldom water their plants correctly (the little hanging bags are the worst they never get watered). Lack of water (and to a lesser extend fertilizer) can can stunt plant until it will never grow properly again.
You have the plants now and not much money invested but a fair amount of emotional investment.
The first plant - you should cut the stem near the base. I would chop it off now sacrificing the tiny bud. Sometimes they never open and the plant can use a rest period to get strength for next year. Do not be tempted to try for branching and additional flowers it is too much for this plant.
The second one is harder. It was discounted because it was badly dehydrated and may not survive. Unfortunately the flower buds also may not open. I want to point out hear that water the plant DOES NOT rehydrate the plant. The roots have changed to where they take very small amounts of water into the plant. You should water modestly until you see new root growth. Full strength watering now is an invite for rot.
The third is the easiest just use a pot clip to stabilize the plant in the pot.
The Oncidium Alliance is typical of how the plants look when neglected. you should expect all those yellow leaves to die in the next few weeks. There is nothing you can do to stop it. The one new growth is your hope. I find unfortunately that these growths have a tendency to rot at the base on a damaged plant. Keep it in lower light do not fertilize (never fertilize a stressed plant), give it good air circulation, and hope for the best.
Everyone should remember their high school biology. Survival of the species is paramount. When this Oncidium is flowering so strongly it can be a sign of impending death (at least from the plants view) and the plant is trying for a last attempt at propagating. The new bulb is also an attempt at survival. However the two attempts conflict with each other. Both are stressful to the plant.
I would enjoy the flowers they cost you less than cut flowers, and maybe you will get lucky and have the plant survive.
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jerry  |