Janet, the issue of water is probably over dramatized for clematis just like the issue of them needing so much fertilizer or needing lime in the soil. A quirk in the gardening lingo that has always driven me crazy is moist well draining soil. To me that is crazy and counter intuitive. How can you have soil that is both?

Do I think that clematis can be overwatered? I am sure they can depending on where you live, your soil conditions, the time of year (early spring vs. summer), and probably loads of other factors that I haven't even begun to think about. This summer in my garden I haven't been able to provide my clematis with enough water due to the high temps and lack of rainfall. Other parts of the country where it has been wetter, the soil more clay like, and the weather not as hot, I imagine you could over water clematis. To me the issue is just so dependent on too many individual factors to make a blanket statement that you can or you can't.

I can probably go out on a limb and say you can't over water clematis crispa too much however since its nickname is bog or marsh clematis. I know that every year I have had it, mine has browned out and all top growth has been killed off in midsummer and I always think I have lost it. Each year up to now however it has always returned in the spring when natural moisture has been more readily available.

I also think that clematis, like most other plants, have survival mechanisms in place to help them if they don't get enough water. This would include allowing parts of the plant to die off to minimize the amount of water required by the plant parts that remain and by dropping leaves to prevent transpiration of water.

I do also think that the type II clematis probably perform better in climates where it is cooler or at least there are less long periods of heat and there is a more ample and even water supply.

Just a few thoughts off the top of my head. I am sure I will think of others later!

I have clay soil and it rains here for months on end and Clematis grow like weeds here until the rain stops and I don't water them enough. Then they die off and brown out.

My water bill was higher this August than any month I can remember and it is from extra watering the Clematis. With over fifty of them, I only had a few that didn't get enough. We had a cloudy/chilly August too.

None of my Clems suffered from anything that looked like over watering. Unless powdery mildew is a symptom and I believe it is also from lack of water.

I think it just really depends on your conditions. My clay soil has tree roots in it so that contributes to drying out.

Yet, I have lost plenty of plants due to rotting out in winter.