This is the time of year you can really find out if you have drainage problems in your yard and garden. Our rainy season is upon us. The next time there is a couple of hours when the liquid sunshine has taken a rest is the time to check how well your soil is draining or NOT DRAINING. It's really not too hard to do. Just look out your kitchen window and if you see mud puddles gathering next to your hydrangeas or your rhododendron or perhaps even worse-in your grass. This is a pretty good indication that you may have some poor draining soil.
Sometimes poor drainage can be caused by external factors. Such as a sloping grade or sinking elevations. These problems can be caused by where your house is located in respect to another house or maybe just erosion from a nearby hill running relentlessly into your yard. These issues can be huge and sometimes impossible to fix alone. But it's important to see what is going on under those shrubs, trees, and PUDDLES.
The Pacific Northwest gets a lot of rain each year. Coupled with the clay soil that is so abundant, we have poor drainage throughout the area in which I live and probably you do too. The clay can be amended and I suggest you do so. Digging into this slippery and muddy soil isn't ever going to be fun but if you can add the amendment, chances are your soil will be breathing much easier.
Some folks want to build french drains on their property in order to DIRECT the water. In theory, this is a pretty good concept. It even looks good on paper. You will want to keep in mind that if the water isn't draining into your soil now, it probably will continue to sit on top of your soil whether you have a french drain in place or not. A french drain will effectively channel water away from an area affected by runoff water. It will not make your SOIL drain better.