I cut a four-foot high yucca plant down to the ground. What will I have to do to the trunk that is left in the ground?
If you are trying to get rid of the yucca, then this article can help you with that: https://www.gardeningknowhow.com/ornamental/foliage/yucca/removing-yucca.htm
I have about four new yuccas from my original plant, but I am not sure of the best way to split them. Do I dig the mother plant out and split them?
This article can help you with that: https://www.gardeningknowhow.com/ornamental/foliage/yucca/separating-and-repotting-yucca-offshoot-pups.htm
Three years ago I cut a stem from my Yucca and put it in water. It rooted!! It now stands at just over 2 metres. I was also given a 'dead' Yucca by my neighbour and watered and fed it and it survived after using a very sharp knife to cut 5/6 slits in the trunk. Lo and behold out came stems and it is now in full bloom and growing rapidly. Is this the norm or am I just lucky? Last year, again, I cut of a stem and put it into water and it has now rooted! From Rob in Germany.
Being able to root them in water with that kind of success is unusual. Normally yuccas root better in soil because they are desert plants and too much water can rot them. But, if it works for you, keep doing it. It sounds like you have the magic touch!
My outside Yucca - the leaves are all going brown and a liquid is seeping out of the lower bark. Is this a sign of a dying Yucca?
This is a sign that the plant is ill. Is the lower stem firm or soft?
If it is soft, this indicates that rot has gotten into the stem. This is often caused by standing water or too much water. It may also be cold damage. Have you had a bad winter where you are? If it smells fishy, it may be bacterial soft rot. Unfortunately, there is no cure for soft rot.
If it is firm, you may have the start of a fungus infection. Treat the plant with a fungicide.
After such a severe winter, most of the yucca plants I have seen have what looks like leaf droop, including the one in my own garden. The top has gone to ''mush''. Is there any chance of it coming back, or should I simply dig it out and replace? There is no new growth from the base.
If the stems are still alive, they will regrow their leaves and there is also a chance the roots are alive and they will regrow from the roots. I would give them a month, and if you do not see growth by then, they are most likely dead. These articles will help you as well:
https://www.gardeningknowhow.com/plant-problems/environmental/how-to-tell-if-a-plant-is-dead-and-how-to-recover-an-almost-dead-plant.htm
https://www.gardeningknowhow.com/plant-problems/environmental/tips-for-saving-cold-damaged-plants.htm
https://www.gardeningknowhow.com/ornamental/foliage/yucca/yucca-cold-weather.htm
I have an outdoor Yucca gloriosa, about 4 years old, which flowered for the first time last summer. I cut off the flower stalk about 3 inches from its base in January, but due to the bad winter, many of the leaves look 'rotted' in the middle and the new growth (leaves from the old stem) seem not to be flourishing. The stem itself has become black and quite soft and I really don't know what I can do to restore it to its former glory. Can you please help?
If the stems are still alive, they will regrow their leaves. These articles will help you as well:
https://www.gardeningknowhow.com/plant-problems/environmental/how-to-tell-if-a-plant-is-dead-and-how-to-recover-an-almost-dead-plant.htm
https://www.gardeningknowhow.com/plant-problems/environmental/tips-for-saving-cold-damaged-plants.htm
https://www.gardeningknowhow.com/ornamental/foliage/yucca/yucca-cold-weather.htm
I have four huge Yuccas that stand about 12-14 feet tall and am wondering what kind of root systems they have because they are next to a concrete retaining wall that forms part of the swimming pool. Are the roots likely to damage the wall, and how easy are they to relocate if neccesary?
It is highly unlikely that they will damage the retaining wall because their roots are not agressive in that way. But they are very hard to relocate once they become established. The roots go very deep and are hard to remove. If any roots are left, they will regrow from them.