What effect does all the recent cool, wet and cloudy weather have on the landscape? How do plants react to that? In general, you would expect a slowing of growth and development. Flowers may be delayed. Size may be less than normal. The good news is that these effects will be mitigated by the abundance of rain. More good news is those plants and trees in flower have retained them much longer than normal. In the nursery our hybrid and Kousa dogwoods, as well as some viburnum, still are in bloom.
You can expect more fungal disease due to the cool and damp. We have seen cedar apple rust and cedar quince rust. Molds and mildew might also appear.
Insect development and activity is also retarded. You may have noticed the absence of gnats—a real treat. Insects that carry disease, like the ambrosia beetle, have been less actively flying and thereby not spreading disease. The same applies to lilac borers.
Seasonal affective disorder notwithstanding, be grateful for all the moisture and coolness. It will soon be hot and dry.