The Big Rains of December
By Vince Scheidt
Most native plant gardeners in the dry southwest get excited just thinking about it. The purists – those who do not irrigate at all – wait patiently through the spring, summer and fall months for the first winter rains to awaken their dormant and thirsty native plants and begin the cycle of life. Foliage explodes out from withered stems, and flowering and seed production soon follow. For the hard-core native plant gardener, this is what it is all about.
Well, December 2010 not only brought the first significant seasonal rains to the southland, but it brought them in extreme abundance! In San Diego County, so much rain fell in December, and with so much intensity, that the ground became completely saturated in many places, with shallow ponds forming in places that had been bone dry just a few days prior. The final storm of 2010 established December as the 9th wettest on record, since record keeping began in 1850 – the same year that California became a state. The last time we had this much rain was 1965! Not many of us were gardening with natives that long ago.
For me, too much rain all too soon caused several of my carefully-nurtured shrubs to wilt and either die or suffer great losses of foliage. Most of these were recently established plants, with root systems just beginning to extend out from the base. Some of the plants I lost had been grown from seeds I had collected from particularly interesting parent plants. I was especially upset to lose an unusual, red-flowering Munz’s Sage (Salvia munzii) that I had rescued in seed form shortly after gophers had destroyed the original parent plant. Others were relatively expensive. I remember paying $13 for a Guadalupe Island Rock Daisy (Perityle incana) that quickly drowned.
Of course, this was a drainage issue. The problem is that my backyard, like many in southern California, was cut into a hillside with only a shallow blanket of organic topsoil placed on top of the natural hardpan by the developer. This mostly inorganic layer of concrete-like material seals the substrate at a very shallow depth. So roots don’t get down very far, and young plants seem to be particularly hard-hit when the substrate becomes waterlogged. My larger and older plants fared better, most likely because they were able to keep at least some of their roots out of the bog.
So the take home lesson is to plant carefully, and design your yard to have good drainage if possible. Better yet, plant species that can tolerate wet conditions and put the xeric-loving shrubs up on a slope!