To water, just water enough to moisten the non-woody absorbing roots. The
non-woody absorbing roots absorb water with elements dissolved in it. They
are mostly in the upper four inches of the soil. During drought the biggest
problem is over watering.
A very good question. I would be careful about using alot of nitrogen
fertilizer about your trees. Large amounts of the element nitrogen can
predispose your tree to sucking insects. The Christmas tree industry
suffers from that predisposition often because the use large amounts of the
element nitrogen to make the trees grow bigger and faster. That places the
trees in a predisposition for sucking insects. Then they spray for sucking
insect. Over fertilizing with the element nitrogen is very common. For
more on predisposition see here.
http://www.treedictionary.com/DICT2003/shigo/ARM.html

Sincerely,
John A. Keslick, Jr.
Arborist
http://home.ccil.org/~treeman
and www.treedictionary.com
Beware of so-called tree experts who do not understand tree biology.
Storms, fires, floods, earthquakes, and volcanic eruptions keep reminding us
that we are not the boss.


wrote in message
oups.com...
This is really a pretty basic question. But my wife and I are a
little new at this, having bought our first house a year ago. We're
doing our best to renovate our yard, which was pretty neglected by the
previous owners.

In our front yard, we have an ancient-looking but previously vigorous
rhododendron, and nearby (about 6-8 feet away) I planted a fairly
young (~5 feet tall) emerald green arborvitae last October. Both
looked nice and green last year.

This spring, we've planted various other small flowers and grasses in
the same area, following the instructions provided for spacing and
watering. I've also given these flowers some all-purpose Miracle-Gro
(again, diluted according to the instructions and given no more than
once every two weeks) and I've thrown some "Holly Care" fertilizer
around the tree and rhododendron, which are supposed to like that
particular fertilizer (it's for acid-loving evergreens.) As the
temperature has warmed up, though, both the tree and the rhododendron
have started turning brown and losing some leaves. The rhododendron
actually started growing a new layer of leaves on top, but all of
these have now turned brown from the outer edge, with the rest of the
leaf being a pale green. The older leaves seem to be ok so far, it's
the new leaves that are looking pretty sad. The arborvitae is
browning from the bottom, but I swear the rest of it also looks a
little thin compared to when I got it.

The other plants in that area are too new for me to really judge how
well they're doing; some do seem to be doing better than others,
though.

We've had some weird weather in the past month or two here in the
Northeast; it was bitterly cold for a while, then we had some
torrential rains (like 4 inches in one day, for two days). Because it
rained so hard for a while, I didn't water at all for about 10 days.
That's when I started noticing the browning, and the soil was cracking
from being so dry on top. I then watered well two days in a row last
weekend, but I don't know if that was right or wrong. The soil itself
is bone dry on top and never seems to stay wet, but underneath it
feels moist (not wet). Keep in mind the rhododendron has been in that
spot for years, and done well, so I don't think the soil itself is the
problem.

My problem is I don't really know how much is a "normal" amount of
water. My wife and I have actually been having some mini-arguments
about it; she thinks that unless there's a drought, you don't really
water at all because all of these things grew in the wild at some
point. I think she's wrong, and in fact all the plants she tries to
grow herself end up dead. (I of course point this out every time we
talk about this.) I usually water trees once a week, and other plants
a couple times a week.

So does it sound like we're overdoing it or underdoing it? How often
should we be watering? (And maybe more important - who is right, me
or my wife?)

Thanks...

Jeff