I don't know where you read such a thing but its ridiculous. Mine got attacked by Spider Mites last year so I trimmed it into this 'pineapple' so I could spray the heck out of it. A couple months later it was filled out again as seen in the bottom picture. Lots of people trim the bottom leaves yearly to keep the plants neater.

"Once you have a yucca, there's no getting rid of it" is pretty near the truth. Cut it down to the ground and it will come back stronger than ever. Its good advice to make sure you really want one and to choose the site carefully.

New growth always comes out of the top although many kinds form colonies.

Different location;

My limited experience with gardening and yuccas was damage to me from the pointed leaves.

Replacing a dry-stream feature necessitated using safety glasses.

Nevertheless, I have now finally succeeded (by manually means) in eliminating all remains of the four large yuccas on that property.

The one in the picture is Yucca rostrata. Its pretty friendly. Its got flexible leaves that blow in the wind, looks quite rhythmic, you can run your hand over the leaves and I've never been stuck by it.

I have had Yucca f. eaten nearly to the nubs by deer and it recovered just fine.

I'd be OK with that one TR!

Hey, Tex - those look pretty cool! I vote to keep them trimmed like that!

Many of the growers/garden designers out there in the desert southwest think that trimming the dead fronds is a no no. Something about integrity of form. As it ages the fronds form a secondary mass. I am neither here nor there about the issue but this guys are adamant about issue. It seems to be a point that people argue about "in the field". Mine looks a bit scraggly right now but given more fonds, I think the mass will develop its own organization. I did trim it up a couple of years ago because of space issue of working around it. I had been poked one too many times. The birds like the disorder underneath the green.

I bought mine about 4 or 5 years ago, I splurged about $45 on it to go in that special corner in the courtyard, thats spending a lot on one plant for me. It was a Monrovia plant named Yucca rostrata 'Sapphire Skies'. The spider mites ended up being a blessing in disguise because its better with the bottom trimmed up. It was easy to cut the leaves off with a steak knife, you can do lots of leaves at a time and it only took me about 45 minutes, the leaves are thin and pliable so the tips don't stick you. I had to do it again this year because it got red spiders again and had a big dead looking side up by the top before I discovered it, who'd of thought they'd attack it in winter while my back was turned?

I hope once it reaches a tall enough height to clear the top of the wall, the air circulation will help prevent this problem, they can reach 18ft. I saw one recently here that was as tall as the second story window at a house. I had no idea they got that tall and came home and googled and yes, its possible. They are hardy to 0 degrees and I read it will grow in as low as zone 5 & 6 around Denver. It needs good drainage but otherwise its not picky about soil.

It is hypnotic watching it move in the wind, the leaves all move together and it reminds me of a musical instrument. So far it has never bloomed but the powder blue color is decorative enough by itself.

Its latest haircut. Poor thing looks terrible right now. Red spiders in winter!!! I really do protest that.

Nope, I cannot handle untrimmed. Sorry--no way. Too messy and its ugly with trashy stuff stuck in it. I've always trimmed mine. The ones I used to have that formed a big multi-yucca village is now gone, took some serious digging as anyone who has removed them can testify. I also trim the Desert Spoon so it doesn't touch the ground and I can clean out the leaves and weed around it. After getting rid of 3 separate big areas of yucca that were here when we bought the house, I am now very selective about which ones I will have growing. You have to be careful with yuccas.

The cultivar I was speaking of just sits on the ground.

http://www.uaex.edu/yard-garden/resource-library/plant-database/shrubs/yucca.aspx

I'd trim it if it was more tree-like, as shown in the photos in this post.

It doesn't make any difference, sorry to be misleading, I was trying to illustrate that they put out new growth from the top even when nearly all the leaves are cut off (butchered in other words). I'm not suggesting you trim that kind. Once established, the root is hard to dig out and will put out new yuccas even if you whacked the whole thing down to the ground.

By the way, all yuccas eventually end up with dead leaves at the bottom whether they are trunk forming or not. They form new leaves from the top center and the old leaves eventually die. You can either trim the dead ones off for a neater look or not. In a residential situation, they look rather messy & collect debris if the dead brown leaves are left on the plant. Anyway, the point of that is, what the deer ate would have eventually become old dead leaves as the yucca grows.

Thank you for the clarification. I know how to proceed now!