Don't know about others but I keep watering until we get rain. Lately our summers are looking more like Calif.........no rain until winter.

I worry about exactly when and how much to water. I've kept my yard in a state of spring, lots of watering, sprinklers going all night, hand-water with hose to reach tree roots in wells, lots of new leaf and branch growth on all trees. Last year around the 3rd week of August the trees showed signs of wanting to slow down -- yellowing leaves, paling, just not reacting as well to watering, so I watered a lot less then. Right now my locusts are showing signs of fall approaching -- some nippy days and overcast does that.

The real rains ended in February. My 300+ swamp trees LOVE rain much more than tap water. Hoping it starts raining in September. Some years it doesn't really rain until November.

The tiny bit of mist we've gotten doesn't count as rain. It hasn't even lubricated the grass enough to enable to slugs to crawl around. It hasn't even been caterpillar spit ...

On the other hand, we had a soaker here a week ago today - 1" of rain that my lawn appreciated very much. 1/4" two days before that.

Lisa, I continue to water during our Aug and Sept, occasionally more newly planted things into early October. That's our dry period, not sure if I'm doing that right but it's what I've always done. Dormancy has to do with temps and daylight hours shortening too, I can remember only one Fall in the last several where we had an out of nowhere hard freeze that caused some damage to young evergreens, knocked perennials to the ground all at once (Halloween).

August and September are often the driest (and sometimes the hottest months) of the year in the Puget Sound area. Continue watering until the fall rains begin.....that can vary widely but typically October is a reasonable time to start tapering off. We may not get lots of rain even then but temperatures cool down enough so that evaporation of soil moisture is much less of an issue.

I've never heard of backing off of watering to "harden plants off" - hardening off is typically associated with increasing cold hardiness. Watering should continue as long as the soil dries out rapidly and the need remains. Well-established plants will require less than those newly or more recently planted. And always water smartly - deeply but infrequently rather than lightly and often. Less frequent but deep irrigation will encourage plants to develop deep root systems and increased drought tolerance so they don't require as much water. Mulching well will also help to conserve soil moisture and reduce the need for supplemental irrigation, too.

Sometimes it is even necessary to water in winter.......but not very often :-)

Thanks for the input. I looked up where I found the "tapering off" of water in August, and it was in Grant, Trees and Shrubs for Pacific Northwest Gardens. He writes: "Water trees and shrubs from April or May onward; don't water after the middle of August except in irrigated areas east of the Cascades" (p. 37, 1990 edition).

I definitely see signs of growth slowing down and a bit of fall color even on some witchhazels, etc. Sure looks different than that "dying of thirst" look in L.A. in August.

Guess I'll keep all the newly planted things watered.

Actually the roots are near the top anyway so if you let the surface layer dry it can be detrimental. And then if you pour on enough water to promote new growth the plant can be damaged by going dry afterward. Better to water frequently for those that need it, particularly the many locally prevalent ornamentals native to or derived from species native to monsoon climates and other regions where it rains all summer.

Plants in heavier soils can hold up much longer than those planted in sandy material.

Usually it doesn't get persistently rainy here until November.

Seattle Rain Festival - November to May

I wouldn't stop watering as soon as it starts raining, often it starts raining in August.