root pruning

[xerophyte_nyc]

One of my (and other northern palm in pot growers) goals is to grow healthy specimens in pots while trying to limit growth to a certain degree, otherwise pot sizes can get out of hand.

There seems to be controversy over treating palms like bonsai, where on an annual or every other year basis, the roots are pruned drastically to stimulate ramification of new feeder roots.  Can palm roots handle this?

I wonder if limited pruning every other year can accomplish this.  Let's say with the help of other people to lift a rootball out of pot, one would proceed to remove a few inches of rootball from the bottom, say about 10% of the root mass, along with some roots on the sides, then replant into new mix.  Eventually, new roots would fill the space.

An alternate would be to grow the plant in a pot with multiple large holes all along the sides to allow room for roots to grow through, and submerge this pot into a larger one with fresh soil mix.  Then, on an annual or every other year basis, the smaller pot can be lifted, roots trimmed back to the holes in the pots, then replanted back into the bigger pots.  The second method would probably be even less of a shock to the rootball.  This can be taken even a step further by submerging the entire pot into the garden for a growing season, but I think that this may result in such vigorous root growth that the resultant trimming might reduce too much of the root mass.

Theoretically, the end result of several years would be a high % of fine feeder roots that are more efficient at absorbing water and nutrients, making for a healthy specimen.

The most difficult part of this method would be to pick a soil mix that has a long life - something like high percentage of perlite with some top soil that doesn't decompose.

Does anyone have thoughts or experience on this?  Certain species that can tolerate this better than others?

I really think this can be pulled off successfully if done without removing too much root mass, and like in bonsai, the formation of new feeder roots can help invigorate new growth for the season.

Has anyone attempted this or something similar? Thoughts?

[PalmGuyWC]

Generally, I try to be very carefull in not damaging palm roots when repotting, or placing one in the ground, however.......when I was planting my palm garden many years ago, I purchased some large boxed single trunked Chamaerops. One of the boxes was so large that it would not fit through the gate in the side garden where it had been growing. The only way to get the palm through the gate opening was to remove the box and shave off about 4" of roots around the entire root ball.

At the time, I thought this was a pretty drastic measure, but when the palm was planted it never missed a beat and grew at the same rate as the others which had no root damage. Of course Chamaerops are very tough palms while some of the more delicate palms don't like their roots disturbed. I've heard that Bismarkias don't like their roots disturbed and that roots that are cut from drainage holes that have grown into the ground will set the palm back when transplanted. I've also heard that certain palm roots will "bleed" when cut and that the cut roots should be cauterized before planting, but I've never done this.

I've also removed many "pups" from Rhapis by washing all the soil off the roots and carefully seperating the roots from the mother plant. Even with care some of the roots are damaged or break off but so long as two or three roots are left undamaged the pups transplant well and soon start to grow in warm weather. As a general rule, I try to not damage or disturb the root ball of a palm, and particularly with seedlings with undeveloped root systems.

I have a couple of unusual Chamaerops that have been growing in large pots for many years, and when the pots are filled with roots, the plants just slow their growth and tend to remain the same size.  Pot bound palms do require plenty of water and in the summer I set them in large saucers to hold water.  On a hot day they can suck up the water in a matter of hours. I suppose this treatment would not work for all palms as the roots might rot.

Dick

[xerophyte_nyc]

Dick

With the pot-in-pot method, you would have the ability to take out the smaller inner pot, free it of soil to expose the roots, and let them be "air-pruned"and whither away on their own to the point they can be snapped off without bleeding.

Bizmarckia are supposedly very sensitive, but I received a couple this spring in the mail, bare-root with only shagnum around the roots, surely they suffered root damage, but both are doing well in pots.

I've never tried anything of what I mentioned in the initial post, I just somehow doubt that palms can be that sensitive if a small % of their roots are damaged, don't a certain amount of roots normally die anyway with age or when they are so lignified that they no longer are capable of water absorption?

[Ken Johnson]

Mark.

When palms are transplanted from the "field" they are lucky if 10% of the roots make it with them. This is often done with no advance root prunning! Monocots are tough. Yes, some need more care but others seem to regenerate roots rapidly and "never skip a beat"

Years ago there was an article in Principies about a "bonsi" cocconut. The plant had been through many hard years as an interior plant and with no fertiliser and little water. The palm was over 20 years old and about 12inches tall!

I like your idea of a second pot with the new roots being cut to retain the original size. After time I bet the old root mass will expan so much that they will crack the pot, unless they are planted in steel. No doubt the palms will be smaller (maybe much smaller) than if planted in the ground but any palm in New York is a good one!

[xerophyte_nyc]

There's no doubt that eventually most palms would bust through their pots, my goal is to perhaps slow down growth while still maintaining healthy specimens.  I realize the limitations.

I have successfully overwintered a CIDP in a garage with minimal light, I think it would be fascinating to be able to keep one for many years while growth is slowed down but still healthy, it would be a fun experiment at least, the plants are readily available.

[FRITO]

Bonsai always intrigued me as a kid.

I found this: http://www.pacsoa.org.au/palms/Articles/BonsaiPalms.html

the key is to keep the palm in mild light with a termperature range of 50-70 degrees or so. it will grow slowly and healthy.

[eastern.nurseries]

Palms make great bonsai especially Rhapis, Chamaedorea, Geonoma and many others . I find sand is the best media and regular root pruning is required. Some palms I've been able to keep in a 100mmm pot for twenty years, Rhapis of course.

[Kris]

Dear Luke  

that's a nice link.

Thanks & Love,

Kris  

[Scott]

Mark - Thanks for posting this topic. I have a few I want to save for a little while until I'm ready to transplant them for a new area.