Recently I have been fascinated by the native wildflower field I planted last fall. Although I seeded it with the same mixture of seeds (mixed with sand to spread them evenly), you can see that we have clumps of different flowers throughout the area.
Figure 1. Descanso Gardens, California
The area where the wildflowers were planted had several 1-2 foot raised mounds; some were in the shape of keyholes. These were built with silty sand from a nearby seasonal stream that had some erosion problems in a rainy year.
Small differences between the temperature, moisture, light and soil on the different parts of each mound have favored different species of wildflowers. In one of the keyholes, I even found some miner’s lettuce (Claytonia perfoliata), a species I had not seeded that favors wetter areas. If I sampled for insects, I bet I might find a similar patchy distribution as well.
As an ecologist/biologist, I am really fascinated by the way that species diversity can be affected by topography, climate, moisture, and soils. As a gardener, I like that I could create conditions that favor different plants just by moving soil around. Plus I think that the waves of color are lovely as well.
Rachel Young is the head of the California Garden at Descanso Gardens, just outside Los Angeles. She has an MS degree in Ecology and Evolutionary biology from UCLA and lectures on various garden and horticulture related topics.