The Big Rains of December

By Vince Scheidt

It’s raining!

Why did this Arctostaphylos 'Howard McMinn' tolerate the saturated ground? Probably because it had been planted the year earlier, so had lots of time to develop expansive roots.

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!

This large White Sage (Salvia apiana) suffered a loss of most of its foliage, but managed to hang in there. It is currently in rehab.

Young Munz's Sage (Salvia munzii), a CNPS-listed plant with a California Rare Plant Rank of 2.2. Once the foliage began to droop, there was no saving this little shrub. Munz's Sage is restricted to southern San Diego County and adjacent Baja California, although it is often used in native plant gardens well beyond the species' natural range.

San Diego Sagewort (Artemisia palmeri), an unusual species with wand-like stems, is associated with mesic slopes and riparian areas. This species tolerated the boggy conditions well. San Diego Sagewort is also a CNPS-listed plant with a California Rare Plant Rank of 4.2.

2 thoughts on “The Big Rains of December

  1. Thank you. I think you solved my nagging question. I couldn’t figure out what was wrong with a salvia apiana I planted last summer that had been thriving, growing, sending out lots of flower spikes. All of a sudden it’s wilting. We had heavy rains in Northern CA too.

    I started this garden in an Oakland weed patch overrun with thistle, oxalis, foxtails. Hardpan 65% clay, no topsoil, no organic matter, chaparral conditions. I’ve been trying to rehab the site and most plants are doing OK to great. But a few, even clay tolerant ones, are wilting this rainy season.

    Is it a good idea to lift the wilting plants 6-8 inches with a digging fork and put manure/rocks/soil mix under them? They’re currently planted at ground level in soil amended with lava rock and horse manure. But not enough, I guess, since the soil is still quite hard and sticky. I’m sure this will break some roots, but might improve drainage. I’m learning native plants as I go, my ignorance is staggering at times.

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