Bulbs are huge and top of bulb is above ground and they blossom but no babies.
The location she has them in may just be too nice. :) Yours may be in a spot that is just a little less "ideal", which is perfect for them as they also tend to have more and bigger blooms when under a little stress. A little stress makes these plants better. When you grow them indoors, it is actually recommended that you keep them root bound to keep them slightly stressed.
It is hard to say what exactly makes her spot less stressful than the spot yours are in - it could be several different things such as sunlight, nutrients soil compaction, etc.. If she fertilizes, then she might what to hold off on doing that for the amaryllis for a season or so to encourage bulblets if she is looking for more bulbs.
Amaryllis normally like to be in a little stress before they will produce bulbletts. Many people will lightly score the bottom of the bulb to encourage them to reproduce.
these are my sisters,I gave them to her,but mine have about 25-30 bulbs per hill but hers has 1 big bulb thats all .I never do anything to mine and they multiply every year
One of my amaryllis plants has suddenly developed a yellow streak down the center of its leaves. I expect that the leaves will yellow completely and eventually die off. What might be causing this? (The other 9 plants appear to be fine. )
It is possible that the plant has amaryllis mosaic. This can cause streaking, but is typically accompanied by a molted appearance on the leaves but does not have to have that. There is no cure for this and the plant will slowly continue to fail so should be removed.
Another cause could be bulb damage from a pest of some kind.
I planted Amaryllis bulbs in the fall and they bloomed beautifully around Christmas time and now they are blooming again. When do they go dormant? Should I hold back on the water to let them go dormant?
I live in Phoenix and it gets very hot in the summer.
The plant likely already went through a short period of dormancy if it is blooming again. I would simply enjoy the blooms and once they die back, the plant should begin to go into dormancy on its own, though cutting back on water would certainly help it along.
The best time for repotting this plant is just following dormancy. That said, you shouldn't give fertilize until it begins to regrow. After which, fertilize the plant regularly with a fertilizer that is high in phosphorus to encourage blooming. If your plant already has growth, then you can give it a low dose of fertilizer once it recovers from the stress of repotting.
I allowed my amaryllis to grow all summer. It still has tall green leaves. Can it bloom again this winter and, if so, how do I prep it at this point?
This article will help with getting them to rebloom: https://www.gardeningknowhow.com/ornamental/bulbs/amaryllis-hippeastrum/amaryllis-bloom-again.htm
I have 4 'old' amaryllis. I put them on my patio as I do every year, fertilize 2 to 3 times and let them grow their leaves until they die. I then put them in cellar --quite dark, near a sink and water occasionally during the winter. When I see the first pale leaf peeking up, I take that plant upstairs to a light window. When it really gets growing, I move it to a sunny window, and get beautiful flowers. DILEMMA! We had a mostly a cold, rainy summer until August, which has been cool but more normal. Two of the pots had finished with the old leaves and I went out to bring them in and found they had already started putting out new leaves. What do I do now?
You possibly won't have blooms on these plants this year. If so, treat themas you usually do, and they should bloom next year.
If I have a 4-inch diameter bulb, how can I grow the bulb larger to get more flowers the next year? How do you grow the bulblet so that they produce flowers?
Use a high phosphorus fertilizer or bone meal. This article will help you with caring for it: https://www.gardeningknowhow.com/ornamental/bulbs/amaryllis-hippeastrum/amaryllis-care-instructions-how-to-care-for-an-amaryllis.htm