How should I amend the soil when planting California native plants?
Don’t! The best horticultural practice when transplanting trees or shrubs – native or non-native – is to use existing native soil as backfill for the planting hole. Roots tend to stay in planting holes with amended soil rather than growing out of the hole to form an extensive and healthy root system. In fact they can encircle the planting hole, just as they do when they outgrow a container, further hindering root establishment. A second problem with amending the soil in the planting hole is that it results in poor water mobility between the planting hole and the surrounding native soil. During winter when there is rain, water in the planting hole will not migrate out to the surrounding soil, resulting in excessive moisture around the roots and crown. In the summer, the plant quickly uses up the water in the planting hole, while at the same time the surrounding soil is drawing this water away from the hole. The plant will need frequent irrigation, and may rot from excessive heat and moi
