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Dead, withered new shoots/culms

Posted: Mon Jun 08, 2015 5:55 pm
by Scurvy
Greetings, I need some help figuring out what's harming some of the new shoots of my stand of Black: Some, not all of the new shoots start out great and then wither and die; here are the specifics:
  • Age of stand: This is start of 3rd season. These were high quality, fully mature, 5-gallon pot starts. Leaves from the original culms are not the same rich green as the new crop of leaves.
    Mature culm height: 14' - >20'
    Older leaves: While the leaves from the original culms show some browning at the leaf apexes and at isolated margins, the leaves are not curling. Most tips are brown back to the where the tip meets the main leaf.
    Sun: Early morning shade provided by adjacent 6' tall fence. Full sun from midday to late afternoon.
    Affected shoots: New hoots start with nice, green, tiny leaf tips at apex. Over time, some tips develop tiny brown spots, and some of these shoots have tips that go all brown and later die. Start out feeling very hard/solid/normal, but the ones that die soften and ultimately the interior developing culms shrink back from the sheaths. These culms/shoots feel very rubbery
    Dying shoots size/height: Mostly 1" - 2" but some have reached 6" and had 1 at 12" and another hit 24"
    Interior culm turns yellow, shrinking back from sheath. The walls shrink back from the nodes
    What's left: When I can break off the obviously worthless shoot, it typically breaks just below ground line. Here it is moist, the sheath portion smells slightly musty, like normal composting plant matter
    Native Soil: Ancient dunes. Water literally falls out. I heavily amended this w/ very organically rich commercial grade gardening soil. The soil still drains VERY well without drying out in my watering cycle.
    Fertilization: Commercially produced, "organic" pelletized fertilizer, heavy w/ "char" components 4-2-2, 1X per month.
    Irrigation: On commercial drip line, single run/18" strip of bamboo, watering 2.5 times/week. In qualitative terms, following the supplier's original instructions, the soil is never soggy and only the top 1" of soil is allowed to dry enough to become less than moist to the touch between waterings. During the Spring growth season, I have been hand watering as needed to keep the soil moist even at the surface, and have been leaving the fallen leaves and culms to act as native mulch.
    Pests: None observed.
    Molds/fungus: None observed,except for the normal odor of rot at the soil line that I can smell only after pulling/breaking off the now dead shoot.
Any thoughts or suggestions will be greatly appreciated. This may be a simple case of a certain amount (~10%) of natural morbidity in the growth cycle.

TIA, Bradley

Re: Dead, withered new shoots/culms

Posted: Tue Jun 09, 2015 6:33 pm
by Alan_L
My thoughts: completely normal. Every one of my Phyllostachys creates more shoots than "needed", and then some percentage of them never grow, or grow a little then "abort".

I don't think it's possible to avoid.

Re: Dead, withered new shoots/culms

Posted: Tue Jun 09, 2015 7:21 pm
by Tarzanus
I agree with Alan. There are usually more shoots than bamboo actually wants to complete. I guess some are there if you stomp on emerging shoot, rabbit decides to chew the nicest, fattest culm or just in case something happens. If nothing bad happens, some shoots abort, usually evenly distributed inside the bamboo plant.

Re: Dead, withered new shoots/culms

Posted: Thu Jun 11, 2015 8:14 pm
by Scurvy
Okay, phew! Thank you for the input. As you have indirectly noted, other than those aborted shoots everything else seems to be going quite well. That said, one thing I forgot about until just now is that through most of our "summer" weather (May 1 - Nov 1), there are substantial afternoon breezes due to the thermal action off of San Francisco Bay, and with last year being a severe drought year, we had many hot, dry, windy days and there is a strong potential for that this "summer" too. I say "summer" because we basically have 2 seasons/year, with this cycle's dormant season running from mid-January to mid-February. It is this wind that may be causing the leaf tip browning.