I have two very large palms (Cordyline australis, the Cabbage Palm) at front and rear of my house. They are around 15 feet high and blocking light to my house and potentially causing subsidence. Can they be pruned back to half their size (would require removal of all foliage) without killing them or do they need to be removed? Thanks. Martin

Hi Martin, Yes, you can cut them back and now is a good time to do so. I'd cut them off about 3ft above the ground (through the trunk) with a view to making them shoot again from the base (they dont normally shoot again from the trunk but very occasionally they do). Once these new shoots are about 2 ft tall, I'd thin them out to just 3 per plant, then you will end up with 3 trunks. If you leave all the shoots that emerge at the base, you will end up with a very dense bush ! One final thing,it may take a while for these new basal shoots to emerge, so dont panic if they take a while.
Doing the above, is exactly the same as if the cold winter has killed the trunk, they will normally come again from the base as described above.
Cordylines have a mass if fibreous roots (along with often a tap root) so its unlikely that they will damage your house, unless they are extremely close.
best wishes, Lannerman.

On 3/12/12 1:50 PM, mtuk100 wrote:
I have two very large palms (Cordyline australis, the Cabbage Palm) at
front and rear of my house. They are around 15 feet high and blocking
light to my house and potentially causing subsidence. Can they be
pruned back to half their size (would require removal of all foliage)
without killing them or do they need to be removed? Thanks. Martin

Cordyline is not a true palm. It is more closely related to century
plants (agaves) and yuccas. The cabbage palm is Sabal palmetto.

Cutting a true palm will usually kill it. It will not produce new
shoots from the old trunk.

Cutting a cordyline will often cause it to produce new shoots. However,
I generally take the top, remove most of the lower leaves, and then root
it as a cutting. I then discard the base.

It would be best to have your plant carefully identified before cutting
it.

I'm not sure why any plant would cause subsidence. Some trees cause
heaving by their surface roots, but that is the opposite of subsidence.

--
David E. Ross
Climate: California Mediterranean, see
http://www.rossde.com/garden/climate.html
Gardening diary at http://www.rossde.com/garden/diary

It can be confusing to know how to prune cordylines. Little regular pruning is required. Just remove dead leaves and spent flowers. The response to hard renovation pruning is usually good but best undertaken in mid-spring. Cut back to side-shoots, basal shoots or to ground level. After pruning, encourage new growth by an application of balanced fertilizer in spring.
Create multi-stemmed plants by removing the growing point before growth begins in spring. Remove dieback or winter damage just above a new side-shoot, or cut back to a sound point on the trunk (below rot and damage).


Remove only brown and yellow fronds (leaves) of Cabbage palm using a pole trimmer. Wear safety glasses and gloves. Prune the stems away from the truck. Do not remove green fronds. Remove any flowers, seeds or berries from the tree so energy will be conserved for tolerating any green leaf loss during pruning. Pull away loose boots around the trunk by hand. Do not attempt to cut old trunk boots off with a saw because the trunk can be damaged easily. Use well cleaned and sterilized tools to avoid introducing disease when pruning. Use mulch around the trunk base to cut down on weeds and eliminate the the need for weed eaters which can damage the tree. Save old fronds to add to compost or brush piles. Never cut the top off a palm tree because it will not recover.

Cordylines, unlike say oak trees, don't actually increase very much in size simply because they get higher. Rather, the crown of the plant mainly gets further away from the ground without getting very much bigger - well it does get a bit bigger but nothing like on the same scale as typical trees. Remembering that it is leaves rather than wood that places the main demand on the metabolism in the roots, we realise that the metabolic load the roots need to service for a Cordyline of a given height in comparison to typical native tree is much, much smaller. So they need much smaller root systems than those native trees. So they aren't going to present any subsidence risk. True palms are similar. I've planted a Chusan palm (Trachycarpus fortunei) - which incidentally is rather more cold tolerant even than a Cordyline - right next to my house and I'm not bothered.

You are actually quite lucky still to have a full-height Cordyline. Most people had theirs involuntarily cut back to ground-level during winters 2009-11.

Cordylines do sometimes resprout from the trunk rather than from ground level. I have seen damaged cordylines with large numbers of new shoots at various levels up the trunks. Typically, though, many will abort, unless you are fairly quick about rubbing out the ones you don't want and encouraging the ones you do want. I think these new trunk shoots are more likely to happen if you just remove the growing tip, rather than make a major shortening of the trunk. So a possible strategy is to cut out the growing tip, retaining plenty of leaves, and see if you get any new shoots part way down the trunk. You could then rub out the shoots you don't want, and later, once the favoured shoots are well established, cut off the trunk off just above the shoots you wish to keep.

Many thanks for the advice. Just to double check that I have the right palm species, I have attached photos. Can you confirm? Thanks. Martin

On 3/13/12 11:04 AM, mtuk100 wrote:
Many thanks for the advice. Just to double check that I have the right
palm species, I have attached photos. Can you confirm? Thanks. Martin


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That does indeed look more like a Cordyline than a palm.

Note that a cabbage palm (Sabal palmetto) has divided leaves in a
fan-like arrangement. See http://en.wikipedia.org/wiki/Sabal_palmetto.

A cordyline is sometimes known as a "cabbage tree", not a "cabbage
palm". It has simple leaves. See
http://en.wikipedia.org/wiki/Cordyline_australis.

--
David E. Ross
Climate: California Mediterranean, see
http://www.rossde.com/garden/climate.html
Gardening diary at http://www.rossde.com/garden/diary

Hi Martin, Yes, you have a Cordyline australis and now seeing the photo, I can see your problem ! I think i'd be inclined to cut it right down and start again from the base. Its a new one on me that you can root the tops as a cutting ????
If it were mine, I'd remove it completely and replace it with a dwarf fan palm (Chamaerops humilis) which would be more in keeping with your available space, its fully hardy (infact much hardier than Cordyline) Another option might be to grow a red Cordyline in a tub (which would have a slight dwarfing effect) and would not ultimately get as big.
regards Lannerman.

Those are wonderful cordylines, but in the wrong place. It seems like vandalism to shorten them. Can't you move them somewhere else, where you might be able to appreciate them as they are? As previously noted, they don't have huge root balls, and can be moved, if you keep enough of the root ball.

You'll just arrive there again if you shorten them. If you like that Dr Seuss look, but not the height, why not grow something of roughly similar appearance, but with less height, such as a some hardy yuccas, or furcreaea, or astelia. Or, as lannerman suggests, one of the red Cordylines that are much more slow growing, in a tub or not. Though the red ones are more prone to cold damage.

Hi again Martin, could this be a terrace in Devoran ??
Lannerman.

I wish it were! It's actually in beautiful Hanwell, West London

Martin