Cabbage Palm Tree? You mean Cabbage TREE? The use of the word palm for the cordylines is a misnomer. They are not palms at all. In fact, they are pretty confusing taxonomically confusing. Some places you will find them placed in the Agavaceae family, and others you will find them places in the Dracaenaceae family, and even further sometimes you will find them place in an 'expanded' family called Asparagaceae. Ive always mostly seen it placed in the Agavaceae family myself. So its definately NOT a palm.

I thought this was about Cabbage Palmettos! LOL!

Anyway, I actually LOVE these plants, and they are commonly sold as Dracena "Spikes" here in the states. I have seen many specimens well over 3' tall and with a trunk here, espeically if they are kept in doors or sheltered through winter from hard freezes.

A quick google search turned up a few things.

"Propagation

Seed - pre-soak for about 10 minutes in warm water and sow in late winter to early spring in a warm greenhouse[78, 164]. The seed usually germinates in 1 - 3 months at 25°c[164]. There is usually a good percentage germination[78]. Prick out the seedlings into individual pots as soon as they are large enough to handle and grow them on in the greenhouse for at least their first winter. Plant out in late spring after the last expected frosts and give the plants some protection in their first winter outdoors[K]. Stem cuttings - cut off the main stem just below the head and then saw off 5cm thick blocks of stem and place them 3cm deep in pure peat in a heated frame. Keep them moist until they are rooting well, then pot them up into individual pots. Plant out in late spring after the last expected frosts. Suckers. These are best removed in early spring and planted out in situ. Protect the division from wind and cold weather and do not allow the soil to become dry until the plant is established. Divisions can also be potted up and grown on until established, planting them out in the summer."

This is from the website Plants For A Future.org

Plants For A Future dot ORG

Also, you may want to read this page listed below

Hope that helps!

~ NPG

Here is a link that might be useful: The Royal Society of New Zeland