While typically grown as a warm-season annual in home gardens, in temperate climates, California poppies (Eschscholzia californica) with a thick taproot can live as perennials.
How to plant. California poppies do not transplant well; seed directly by broadcasting seeds or planting individual seeds. Save water by planting poppy seeds just before a forecasted rain; under the right conditions, no additional water may be needed for germination.
Temperature requirements. California poppy seeds germinate best at temperatures of 55° F to 70° F. Excessively hot temperatures early in the season can destroy blooms and potentially kill plants if they have not yet established a deep tap-root. Well established plants will become dormant during the hottest part of the summer. Plants may withstand light, occasional frosts early, but are typically killed below temperatures of 20°F.
Soil needs. California poppy prefers sandy, dry, or rocky soil with exceptional drainage. California poppy thrives in soils with relatively little organic matter and fertility, and prefers neutral to slightly alkaline soil with an ideal pH from 6.5 to 7.5. It does not need the rich, fertile soil required by most vegetable plants.
Water requirements. The California poppy is a California native plant and is ideally suited to thrive in California’s Mediterranean climate of cool, moist winters and warm, dry summers with minimal additional water. California poppies can be grown using only winter rains. However, GardenZeus recommends keeping newly planted seeds moist until they germinate. If early spring weather is particularly warm and without rain, water young plants. And adventitious gardeners may promote a longer flowering period and fuller growth during hot summers with occasional, deep watering. Occasional, deep watering will also help plants to develop a fleshy tap root, the key to the poppy’s drought tolerance. In extreme drought conditions, give poppies supplemental water, especially if plants are less mature. Excessive water, especially in poorly draining soils, can kill California poppies.
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