You actually have a Yucca guatemalensis. Old name (now a synonym) was Yucca elephantipes.

If Yucca guatemalensis is in the shade, the leaves become limp and long so they can absorb more light. In bright sun, new leaves grow straight and stiff. But they're ok in full sun to shade.

You are right to improve drainage, Yucca guatemalensis is from dry areas, so it's drought tolerant, and continuous moisture around the roots will cause them to rot.

I would just pot it as it is and water well the first time, and keep it out of direct sun so the roots can recover.

Here is a link that might be useful: Yucca guatemalensis link

And yes that is scale on the leaves.

Here area couple of links:
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7408.html

http://www.ipm.iastate.edu/ipm/iiin/housepla.html

Thanks treeguy. The Iowa State link above says "nless the plant is particularly valuable, many people find it best to throw away infested plants before the pests spread to other houseplants."

I don't particularly want to throw it out, but I'd prefer to do that rather than risk it spreading to other plants. What would you do?
deburn

ugh, scale. I am dealing with some right now on a schefflera & a f. benji.

#1 !! Segregate the infested plant - scale is slow, but it does travel & will infest your other plants. If your plant was in amongst others, check them thoroughly for scale as well - in fact, check them all in any case, just in case. Usually one plant has it worst & there are some others on close neighbors.

#2 Wipe the leaves of scale bugs; they come off pretty easily. I use a dilute solution of Neem oil & a disposable wiper cloth. Your garden store will have Neem - if not a bottle of 100% Neem oil, then look in the roses section as Neem is also an anti-fungal. There is some good info about Neem on this forum, just put Neem into the search.

#3 Your plant has not been experiencing the best conditions for a while now - compare the scale (each spot is an individual insect) to a flea or tick infestation on a dog. Root pruning or a radical potting medium change (say from soil to soil-less) might be tough for it right now. You might use a potting medium that is more transitional: faster/chunkier, but still with some soil or organic matter and pot again in late spring, once your plant is feeling stronger. There will probably be several opinions on this :)

#4 KEEP UP with Neem spraying! Or whatever anti-insect treatment you choose. Scale is very persistent. Keep segregation & keep checking your other plants. You can spray down with Neem once a week. It suffocates the scale & discourages them from feeding. Neem is stinky, but it does work. Beware spraying plants in full sun, there will be a reaction; dusk is best.

Good Luck!

Thanks gravyboots, that's grim news. If I were to remove the affected leaves would that help any?

Don't bother to remove affected leaves, it looks like a bad infestation and the scale are probably everywhere.

Those roots sure look dried out, hopefully just the lighting. A root pruning wouldn't hurt at all, and much more likely to be highly beneficial. I see no reason to do any top pruning.

If it was my plant lying on the paper in the first photo, and I really wanted to save it while protecting my other plants from it spreading, to the greatest degree possible, here is what I would have done/would do.

* Before repotting, I would first have treated the scale. I would have taken the plant outdoors and used a topical spray containing the systemic Imidacloprid, following directions. Imidacloprid is approved for use on houseplants as a soil drench, but they don't want you spraying it in your kitchen or living room. I would have followed the Imidacloprid treatment with a treatment of all-season horticultural oil after a 1 week interval, again being extremely careful to coat every surface. It probably wouldn't be needed - just insurance. The all-season H oil is sometimes referred to as 'summer oil' or 'perfect oil'. If you have an aversion to using the Imidacloprid, the oil may be enough if you're very careful to saturate every surface of the plant.

* I would then have waited until early summer to repot the plant.

* Assume the roots would look like they do in the first picture. There is sort of a break in the main mass of roots below the stem where you can see a lot of white paper - then there is a lesser mass of roots below that. I would have cut the lower roots off, and pruned out any roots that look like potential trouble.

* The plant would have then gone into the gritty mix, and would have been fertilized with a 3:1:2 ratio (different than NPK %s) fertilizer at 1/2 recommended strength.

* I would have made sure the plant got plenty of bright light, and that soil temperatures were 65-75*

Al

Let's clear up some misinformation here. Yuccas are tropical plants and are non-seasonal, so they can be repotted or pruned at any time of the year.

When you say it lacked draiange, you could mean it did not have a draiange hole or there was no drainage material in the bottom of the pot or you feel the soil mix was not porous enough. A draiange hole is important. Using a layer of drainage material in teh bottom of a pot is an out-dated practice that is never used professionally because it actually serves to keep soil moist even longer. The plant looks healthy (other than the scale) and exhibits no signs of over watering or poor drainage, so I doubt that soil quality was an issue.

Total soil replacement is almost never a good idea. The tiny root hairs, which do the bulk of the work for the plant, are invariably damaged when all the soil is removed. It makes recovery much more difficult.

That said, move the plant into a terra cotta pot that is the smallest that the roots will fit into snugly, but without squashing them. Then use a potting mix that has lots of peat moss and perlite. That mix will drain more quickly and by keeping the pot small, then the soil will dry out sooner.

Before you repot, wrap the roots in damp paper towels and plastic. Then treat the scale. A solution of 5 parts water to one part rubbing alcohol and a squirt of liquid dish soap can be very effective if you thoroughly drench all leaf and stem surfaces, especially the crevices where the leaves join the stems. Thoroughness is the key because if you miss a few, they will survive and reproduce. Everything should be dripping wet after you spray. Repot after you spray.

Scale does not spread quickly. Once you have treated your Yucca properly, there is no reason to isolate it from other plants. If you are thorough, you may not need to spray again, but you should continue to be vigilant and spray when needed. If there are a few leaves that are badly infested, you can remove them before spraying so there is that much leas leaf surface to spray.

~Will Creed

While it's true that you CAN repot tropicals at any time, it makes good sense that since growth and metabolic rates vary considerably between winter and summer, that the period immediately before the most robust growth would offer the fastest recovery. Repotting a plant now or during the winter, especially a plant already obviously weakened, ensures additional stress and an unnecessarily long recovery period, which leaves the plant more vulnerable/susceptible to insects and disease for a longer period than plants repotted in summer.

Just to clear something up: Drainage layers CAN be made effective if the particles in the drainage layer are less then 2x larger than the particles in the strata above. It is the size disparity in the particles that determines how the water reacts at the strata interface.

Additionally, drainage layers don't keep soils moist longer. If you think about it, drainage layers hold almost NO water. If the volume of the pot occupied by the drainage layer was occupied by soil, the soil would hold considerably more water than the drainage layer. Therefor, drainage layers reduce the total volume of water a pot is capable of holding. Less water = dries faster, not stays moist longer. Essentially, drainage layers do two things. They elevate the position of the perched water table in a container, and they reduce the total volume of soil the container can hold, and thus the total volume of water a container can hold.

It's better to build/use a soil that holds enough air and drains well than to employ a drainage layer. One method decreases water retention by increasing aeration, and the other simply reduces the volume of soil available for roots to colonize. (Or use a wick; wicks rock when it comes to dealing with water-retentive soils.)

How large or small a pot can/should be is a function of plant mass and soil choice. Soils constructed so they hold no, or very little perched water, have no upper size limit when it comes to pot size. It is only when using soils that support perched water that 'over-potting' and pot size gains 'critical decision' status.

Take care.

Al

Thanks Rhizo, Will and Al.

I knew I wasn't going to be able to treat the plant for a couple of days and I definitely didn't want the scale spreading to my other plants, so I kept it outside last night, covered with plastic!

probably not the ideal solution, but it was the best I could do in the circumstances