You hear it often that Autumn is the best season to plant in California. This is true, but you can plant in the spring. And how can we not be outside when the weather is so gorgeous? And really, we must do something besides battling weeds, right?
There are many California native plants that can work quite well mixed with “exotics,” that is, plants from other states and regions of the world. As long as you match soil type, sun/shade and water requirements, you do not have to rip out your whole landscape to include some of our own state’s natural treasures. There are, however, a few tips to help ensure success with native plants. These tips also apply to plants from other Mediterranean climate regions and from desert areas and have to do largely with reducing the chances of death by root or crown rot, which are diseases prevalent in many of our soils. They are not a problem when warm soils are kept dry or are quick-draining but are the leading cause of plant death when we put chaparral or scrub plants such as manzanita, flannel bush, Ceanothus, and sages into our loamy or clay soils and then water them all summer.
The first tip is true for all plants, and that is to dig the hole at least twice as wide as the container and only as deep as the plant was in the container. In fact, for woody perennials and shrubs, it is better to plant about one inch higher than it was in the container, even if some of the surface roots are exposed. Herbaceous plants, vines and grasses are less particular, but don’t plant them too deep either. The new roots will want loose soil with some oxygen directly horizontal, and this helps prevent the roots from continuing to circle, which they have been trained to do in the pot. If the plant is rootbound, you may need to dig mini trenches to gently stretch out roots and train them to go straight rather than continue to curl or double back on themselves. Spending this time at planting, or directing your planting crew to do it right, will increase your chances of a vigorous plant that will eventually become drought resistant.
In heavier soils, I have had some success planting woody perennials and shrubs on berms. Remember the old-fashioned way of planting squash or melons? Pile enough soil up so that when you are finished planting the entire rootball is raised from the original ground level. This helps the irrigation water to run off, in effect creating a mini slope and improving drainage.
The second tip is to plan your irrigation so that drippers can be moved away from the crown as the plant matures. Many native plants such as manzanita, Artemesia, Ceanothus and the woody sages and nearly all trees do not like water on mature wood during the summer months, and this susceptible area should remain bone dry in summer once the plant is a few years old. Moving the emitters to halfway between the crown and the end of the branches is a good rule of thumb, and helps when doing irrigation checks.
The third tip is to NOT fertilize. Don’t add amendment to the planting hole; don’t throw in some time-release pellets; don’t drench the plant with foliar or ground “Triple-16;” don’t try to change the Ph, etc. California native plants do not need to be fertilized. It is one of the things we love about these plants; they save us in time and money by asking practically nothing from us except to choose the right plant for the right place. In fact, on soils that have a history of fertilizer, such as on old citrus groves or dairies, we work to leach both excess nitrogen and salts out of the soils as quickly as feasible. We don’t always like quick flush growth in native shrubs and perennials, for this often shortens their lives.
Choose plants that suit your garden, plant correctly, use mulch, keep plants well watered in winter and spring, less but some water in summer and fall, and don’t worry about fertilizer or pesticides. Voila.