Prosartes lanuginosa - old stem question
Laura & Dave (Sun, 09 Dec 2012 13:25:22 PST)

Hi All
I've been doing some very tardy repotting of some older plants (tardy both in
years and season, I'm afraid). The Prosartes (Disporum) lanuginosa have been in
the same pot for about 10 years. When I unearthed it, there were three or four
terminal shoots, and many inches of rhizome from previous years, with an
inverted forest of roots for their whole length, many of which don't appear
dead. Unlike Trillium, which seem to allow the oldest parts of the rhizome to
rot away after so many years, the Prosartes I know (lanuginosa, and our native
hookerii and smithii) all seem to keep the old rhizome around. Repotting
plants, with these old tangled root masses requires a large pot, and lots of soil.
My question is whether these old parts are really contributing to the growth
of the plant? They appear to be very woody, so that they wouldn't be much good
for food storage. And transport of water, nutients and gasses I would think
would also be impeded. It's interesting to be able to trace the path the
rhizomes have taken over the years, but not too helpful.
I'm thinking of cutting the old parts away when repotting, leaving a 2" to 3"
piece to pot. If I'm correct in my guess about the life stage of the older
parts, I'm guessing that they wouldn't have the energy to initiate side shoots
(but I'd try a few just to find out, of course).

What do others think, or have experience with.

Thanks,
Dave Brastow ... Tumwater, Washington (USA)

P.S. Wow!! My first flower ever of Zephyranthes macrosiphon opened this
morning! Many thanks again to all for the wonderful seed/bulb exchange, and the
PBS as a whole.