We Sometimes Get Bamboo Questions Too
Cactus Jungle: Greetings,
I am very worried about 12 bamboo plants (Psuedosasa japonica) I bought from you a little less than a year ago, which I have planted outdoors in large redwood planters in an alley behind my house in Noe Valley, SF. The alley is fairly narrow E-W running – the plants get direct sun during the mid-day hours because the hill I’m on slants towards the south. I water them once every week or two, and this spring have given them one dose of fish emulsion. While there are new shoots coming up at the base of the plants, a noticeable portion of the leaves are beginning to yellow or brown – worrisome during the fair springtime weather. Additionally, there is an apdhid infestation on the plants – they exude an oily residue covering the leaves. Do you have any experience with this problem?I have invested both time and money into these plants and am not thrilled to see them fail in less than a year. Please see the attached jpegs: I would be most grateful if you have any advice or information which would help me care for the plants. As far as I can tell the species is appropriate for the climate, but let me know.
Many thanks,
Benjamin
Benjamin,
The yellowing leaves is from stress, from the aphids (sucking like
vampires on the leaves) and the fact we have had a very dry spring and
the plants are thirsty. Aphids are usually not a problem if the plant is
getting enough water and nutrients, all though they are often an issue
while recently planted plants are getting established. As your plants
mature they will become less prone to aphid problems.
You should spray the aphids off with a blast of water from the hose.
There are easily washed off and be a soft insect are usually fatally
injured by a good jet of water. You can also use insecticidal soap or
Neem Oil, but only use them after our “hot spell” that has just started,
is over. Hot weather and insecticides are a bad combination for your
plants! Spray in the evening, not during the day or morning as the soap
and or Neem Oil can cause leaf burn in the hot sun. I would recommend
using a hose end sprayer and really coating the leaves to kill off the
remaining aphids and eggs glued on to the leaves.
In a raised wood planter like yours, the bamboo is going to need a bit
more water than if it was in the ground (where its roots could pull in
moisture from all around). The wood breaths and so the soil inside dries
out faster. Water well, at least once a week, dry soil can be hard to
re-wet, so a slow soaking with a trickle of water is usually best, a
soaker hose ran down the length of your planter, twining between the
plants is an easy way to water your bamboo. Give it more water if it is
warm and windy, as this dries the bamboo out faster through
transpiration in the leaves. After a year in the ground you should be
able to water less, since the plants will have better established root
systems to pull in available water, but remember that raised beds always
take more irrigation.
They should “Out Grow” the aphids and stress pretty quickly as long as
our projected drought holds off long enough for them to get established.
Psuedosasa japonica is a great drought tolerant bamboo but like all
young things needs a bit of care to grow up strong enough to face the
big, bad world… I think your will take off with a bit more water and
knocking down the aphid infestation.
Good Luck,
Hap
