With more than 70 inches of rainfall recorded on Mt. Tamalpais this season, the deluge may be more than some yards can handle. Did you experience torrents of water pouring off your roof and pooling around your treasured shade trees? Puddles spotting your lawn or ponding in your veggie garden?
Why is too much of this precious stuff a problem? Basic healthy soil is composed of soil particles, air, and water. Air in the soil is vital for plant growth providing oxygen for roots and soil organisms. When water fills up all the available air spaces, the soil is said to be saturated (waterlogged), and any additional collects on the surface in pools and puddles. This standing water limits the available oxygen to plant roots, suffocating them, and making them more vulnerable to attack by disease causing organisms.
If you had standing water around your trees, they may display symptoms like leaf yellowing, leaf drop, reduced leaf size and shoot growth and dieback at the crown or top of the tree. If the trees have also suffered from drought, they’ll be more prone to injury. If you are concerned about the impact of too much water on your trees, don’t hesitate to consult a certified arborist; mature trees are often a garden’s most valuable asset.
And while the rainy season may be winding down, consider improving drainage in areas where you had puddles and ponds for more than a few days, so that you’re prepared if we have yet another wild, wet winter with too much of a good thing.