If you think natives are difficult to grow, you haven't talked to Krzysztof Kozminski. Five years ago, the hot, dry, windy backyard slope of his one-acre property in San Jose had only a few small plants in the backyard. Today, dozens of varieties of California lilacs and other native shrubs flourish there.
He described his method, which he calls planting in mud, at a recent meeting of the Gardening with Natives group of the California Native Plant Society.
Kris starts with one-gallon plants, which he has found adapt better to his hard clay soil than larger pots. He starts planting after the fall rains have softened his soil enough so he can dig a small hole, around November, but no later than January. By planting when the soil is already moist, he ensures that the new plants do not dry out before they can grow new feeder roots.
Anyone who has bought a plant from a nursery knows that the potting soil is looser and richer in organic matter than most native soils. If you have clay soil, digging a hole and popping the plant in the hole would be like planting in a clay pot.
So the method usually recommended is to dig a hole larger than the pot, scoring the sides so they are not slick, and either refill the hole with potting soil around the plant or else mix new potting soil with the native soil.
Kris uses a variation of the latter method. First, he uses a post-hole digger to make a hole a little bigger than the pot. The dug-out soil goes into a wheelbarrow, where he hoses some of the potting soil off the roots, at least an inch on the sides and bottom and a couple inches on the top. The soil washed off the top is replaced with native soil, preventing the wicking effect of potting mix in the summer, and also preventing flooding in winter. His son mixes the potting soil and the clay with enough water so the mixture is the consistency of pudding.
The soil pudding goes into the hole, and with rubber gloves up to his elbows, Kris sticks the plant into the mud, keeping the crown of the plant an inch or so above the original grade. He pools the rest of the mud around the plant.
After the water drains, he covers the area around the plant with mulch, keeping the mulch away from the crown.
He waters the plants only the first year. After the spring rains end, he waters every couple weeks until the end of June, then every 3 weeks through the summer, then monthly in September and October. But sometimes his watering schedule is modified to “when I remember or have time,” so some plants have gotten only one watering until July.
In subsequent years, the plants get no water. That means no irrigation system is needed, and the only maintenance is replenishing mulch.
Using this method, Kris boasts a 90 percent survival rate. Some of the plants grow 6 to 7 feet high within 2 years. His method has worked especially well for California lilacs, currants and gooseberries, native buckwheats, sages, and fremontodendrons.
© 2008 Tanya Kucak