Trimming Roots of Potted bulbs

J.E. Shields
Fri, 21 Mar 2008 05:21:30 PDT
Ken asks a very good question.  I habitually work very hard to spare the 
roots of clivias when repotting or washing for shipment -- but I saw 
workers repotting clivia plants at a California commercial nursery, and 
they were chopping off half the root lengths, then repotting in the same 
pot with fresh potting mix.  What are we seeing here?

Some plants in the amaryllis family seem to have to struggle to grow new 
roots when the old ones are damaged or removed.  Haemanthus, Crinum, and 
Clivia are a few examples that come to mind.

The thought occurs to me that cutting off part of the roots may stimulate 
the growth of fresh roots, but I don't know if this is actually what 
happens. For sure, the gardening literature is full of "old wives' tales" 
that are not true, or are at best half-truths based on poor understanding 
of plant biology.

Jim Shields
in chilly central Indiana (USA)

At 09:09 AM 3/20/2008 -0700, you wrote:
>Dear Members:
>         In a current article on Pot Culture of Lilies,
>one of the comments made is that the roots are trimmed
>to 2 1/2 to 3 inches.  For years, the claim was made
>that imported lily bulbs didn't grow well because the
>roots were usually trimmed.  Well, is the claim faulty,
>or is trimming the roots a bad suggestion?
>         Then, I was taught that roots were only able
>to absorb nutrients for-at most-an inch back of the
>growing tip of the root.  Trimming roots back would
>remove the part that is able to absorb nutrients.
>Yes, the roots are possibly old, but any possible
>new growth is being sacrificed.  Yes, lilies do make
>new roots, but why not either remove the roots
>completely, or not trim them at all?
>         Admittedly, roots also serve to anchor the
>plant, and a couple inches would be better than none,
>but why injure the roots instead of potting up the
>whole root system?
>         There are a lot of "old wives tales" in
>gardening, things that are done because that's how
>it's always been done.  Is this an example?

Jim Shields             USDA Zone 5             Shields Gardens, Ltd.
P.O. Box 92              WWW:
Westfield, Indiana 46074, USA
Tel. ++1-317-867-3344     or      toll-free 1-866-449-3344 in USA

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