Curious growth differences on draceana

Hi all

I planted these dracaenas about 4 years ago and when I planted them they were equal in size, really small plants in 1/2 gallon pots each. By now the left one is about twice as tall as the right one and the middle one is about twice as tall as the left one, in addition it sports a new growth from the bottom.

As if it weren't strange enough, the leaves of the tallest plant look really bad with these yellow spots all over.

If anyone has any explanation for the size differences I would like to hear it. Also if you could ID the plants themselves, thanks. And finally, what are the spots from? Apparently whatever causes them does not harm the plant at all, maybe it makes it grow faster???

Many factors are at work here, impossible to know which of them has caused one plant to grow more slowly than the other.

One may have developed a better root structure at the propagation stage. One of the planting holes may inadvertently have been surrounded by hard soil, or developed a drainage issue. Even something like the wall foundation concrete leaching more heavily from a spot closer to one plant could have created a major pH differential, and affected the relative availability of various nutrients.

It could also be lighting --if your picture is Northeast to the left, the larger plant could easily have shaded the other over the years (note the plants close to the wall on the right are shaded and smaller).

I don't think the pest problem created the growth differential --looks like some sort of mite, but I've not seen dracaena attacked in that way.

Looks like Cordyline australis.

Do the plants all get the exact same treatment? Doesn't look like they have any problem. The spotting could be from bug bites.

Thanks for the ID, it does in fact look like Cordyline australis.

The plants are getting no special treatment, they are watered in the summer, I put compost under them sometimes. The biggest and smallest plants are next to each other so I can't even consider some negative force on the right side that weakens as we move towards the left. At any rate, it is quite interesting.

The wall on the left faces West, the picture was taken in the late afternoon hours with the Sun beginning to set.

In that orientation, the smaller plant (left) would have gotten MORE sunlight. My sunlight theory is clearly wrong for that one, but could still apply for the smallest one in the corner --shaded out by the big one. Corollary applicable to the lefty: if the water source is in the corner, the stronger growth could be from lefty shading the soil in which the larger grows, allowing it steadier moisture, while the sun has kept the lefty's soil hotter and thus drier.

I'm more inclined to think it's a combination of relative soil conditions and root growth restrictions. The smallest has two below grade concrete surfaces affecting its root soil --could be too high a pH resulting. Lefty has the least shaded soil. And both smaller ones could have ended up in planting holes constrained by construction debris, or by hunks of rock or clay that impeded tap root growth, increasing their reliance on near-surface moisture.

It could also simply be that the different plant genetics have fostered the diffferent growth rates, of course.

Very interesting thoughts, thanks. Maybe I'll apply some soul acidifier in the corner and see what happens.