All the long pointy leaves of my yucca plants look bad. Can I just cut them all off. Will they grow all new leaves then? Seems like I did this once and they didn't bloom that summer. Is that because of the drastic cutting of the leaves?
For pruning instructions, this article will help:
https://www.gardeningknowhow.com/ornamental/foliage/yucca/yucca-plants-care-and-pruning-tips-for-pruning-a-yucca.htm
I work at a golf course and we have several Yucca plants. This past winter a lot of them became flat. Do they need to be transplanted, or do they just need pruning? When pruning, do we cut all the leaves back? Really not sure how to handle them.
These articles should help with that: https://www.gardeningknowhow.com/ornamental/foliage/yucca/yucca-cold-weather.htm
https://www.gardeningknowhow.com/ornamental/foliage/yucca/yucca-plants-care-and-pruning-tips-for-pruning-a-yucca.htm
A friend gave me some yucca tubers. I put them in a big box out on my deck. I just noticed after a week that they are molding. What should I do, and will they still grow?
As long as they are still firm, they will grow. You can use a damp cloth to wipe the mold off, but as long the tubers are staying firm, you don't really need to worry about removing the mold if you don't want to. Wrapping the tubers in newspaper will help to wick the moisture away that causes the mold.
I have had my yucca for almost seven years, and in the past, have trimmed the dead stalk leaves in the spring without issue. This year, however, all of the leaves look terrible. They are crusty and dead. If it weren't for a few small patches of green leaves here and there, I would think the entire plant was dead. Can I cut the whole plant down to the ground without permanent damage? Will the leaves grow back as if I trimmed them individually?
Yes, the plant will normally come back, and in some cases are even quite difficult to get rid of due to this. Here is an article that you may find helpful: https://www.gardeningknowhow.com/ornamental/foliage/yucca/yucca-plants-care-and-pruning-tips-for-pruning-a-yucca.htm
Our outdoor yuccas have round brown spots on them. How can I get rid of this? I have already pruned them up, but there are still some leaves on them.
You may either be overwatering or there may be an issue with the roots. Water only if the soil is dry to the touch. If you are already doing this, check the roots for root rot.
I have never had yuccas before and there seems to be a lot of brown, dead leaves. I don't know whether to clip it all back and have been told if I do this it won't bloom. Please advise me on what to do. I live in Zone 4 and do like this plant.
The brown leaves are most likely due to cold damage and can be cut off. These articles should help you: https://www.gardeningknowhow.com/ornamental/foliage/yucca/yucca-plants-care-and-pruning-tips-for-pruning-a-yucca.htm
https://www.gardeningknowhow.com/ornamental/foliage/yucca/yucca-cold-weather.htm
I pruned my Yucca plant on three of its stems, which branch out from the main stem. All three are now growing new shoots, but lots of them. If left alone, they look like they will all collide. Should I pick the best ones and cut short the ones which are growing in an odd direction or too close to one another? If so, then what is the best way to cut or stop them from continuing to grow this way?
Yes, picking the best ones would be best. You can cut them off at the branch point, or at whatever point the branch starts to become a problem.