This is a public-interest archive. Personal data is pseudonymized and retained under GDPR Article 89.

Re: Cork oak in the lawn

Nan, you replied to me with:

"Well, Andrew, the lawn is a tall fescue, we don't water at all from about
October until...., well, I've yet to turn on the irrigation system this
year, but normally, we probably start irrigating again around March.  We're
in fairly sandy soil, so the drainage is quite good, the lawn is over a
leech (or is it leach?) field from the septic tank, and in the hottest part
of summer, the maximum watering is about 30 minutes three times a week.
Otherwise it's twice a week.  What do you think?  Will it get root rot?"

I hate to sound like a guru on the subject because there are a lot of
questions about it that I can't answer. However, in view of your facts I'd
say you have a good chance with it if you follow the bottom line
instructions. Water from your leachline (I think it has the 'a') will
sustain it through any drought although I do not know what the roots will
do the the leachline. Surprisingly, the leachline is less likely to cause
root rot than the weekly watering from above. In the river valleys in
Southern Spain where many grow the deep roots reach groundwater below the
dried-up rivers and they use it to survive the long drought. Maybe the root
rot fungus grows only in the upper layers. That's just a guess, not a
proven fact.

You probably know that the coast live oak (Quercus agrifolia) will tolerate
summer watering if it is planted as a young sapling and treated that way.
Old native oaks that grew up only with winter rain do not usuallly survive
the application of water in summer. Maybe the same is true of Quercus suber
as it is not for decoration that they developed a corky bark.  You are
probably familiar with the cork oaks at Quail Botanical Gardens. About 8 to
10 years ago they were showing signs of distress as a result of the
watering going on. Several did die. Azaleas planted beneath them were taken
out and the amount of watering was reduced. I don't think they are fully
recovered yet but at least they were not dying when I looked last time.
These trees had been planted under a different watering regime, with little
or none and did not like all the extra watering.

Bottom line is: Either plant a young oak , Q. agrifolia, Q. ilex etc. and
maintain your watering regime or plant Q. suber and either cross your
fingers or cut down your lawn watering. An hour and a half per week is not
a low level of watering.

Andrew
San Diego, California
awilson@fda.net
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index