Bamboo stops growing after several feet
My bambusa old hamii is having a rough season. I see 3 separate problems and am hoping someone can shed light on them to help me remedy.
1. Some of the shoots spring up quickly and look perfect until they reach a certain height usually about 6 to 10 feet, then the culms seem to pancake in on themselves (almost like a telescope that gets closed up). There seems to be a black spot on the surface and it rots inside at that point. Everything under the rotten area seems healthy (but short).
2. Healthy leave shoots are falling off, almost as if something is chewing them off. This bamboo screen that I planted once hid the neighbors house, but now with so many leaves falling the house is in plain sight and the bamboo looks miserable.
3. I see evidence of mealy bugs. It seems I've had these awhile and hasn't been too much of a concern. Now however they seem rampant. I've sprayed them using dawn dishwashing liquid several times during the summer. I've hesitated to put any insecticide on the leaves/stalks as I have so many hummingbirds and other small birds in the area. I'm okay to use a systemic insecticide, but have yet to do that. Any suggestions?
Some background on the bamboo: Planted about 25 containers of 5-6 foot stalks approximately 5 years ago. Have grown wonderfully until recently. Live in Hermosa Beach, California. Has mostly morning sun, but has had less as the deciduous tree in front of it grows taller. Use soaker hose watering every day for about an hour (except this winter) and have been letting what rain we have water it. Prior to this year, I've just left the soaker on most of the year and all was well. I fertilize it about every 3 months. Keep a layer of its own leaves as mulch. Put home grown compost on in the spring.
I know this is a lot, but I've yet to find any information on 2 of the 3 of these problems.