Deadheading (removing the spent blooms) can promote additional flowering. However, if you want your plants to self-seed, leave some flower heads on to drop their seeds. Moreover, plants grown in hot climates and in containers are typically short-lived and often treated as annuals. Many gardeners prefer to pull them after they’re done blooming and plant new seeds the following growing season.
Light
California poppies grow and bloom best in full sun, meaning at least six hours of direct sunlight on most days. The more sunlight, the better. Poppies grown in shady conditions often will look ragged and more easily succumb to diseases.
Soil
Whereas many flowers need rich, loamy soil, California poppies can thrive in poor soils. Sandy and rocky soils both provide good conditions for California poppies. What doesn’t work is heavy clay soil because these plants need sharp soil drainage. If you have clay soil, try planting in a raised garden bed or container instead.
Water
California poppies require very little water and are good candidates for drought-tolerant xeriscapes. Sporadic spring rainfall is usually adequate to irrigate the plants. In areas with hot summers, the plants will often go dormant and need no additional irrigation during this time.
Temperature and Humidity
The warming of the soil in the spring, combined with moisture from spring rain, will trigger germination of California poppy seeds. As long as temperatures remain mild, between 50 and 75 degrees Fahrenheit, California poppies will continue to grow. Excessive heat can cause dormancy. However, when cool temperatures return, the plants often will regrow and even rebloom. Moreover, California poppies prefer low to moderate humidity levels. In high humidity, good soil drainage and airflow around the plants are essential for them to stay healthy.
Fertilizer
No fertilizer is necessary to successfully grow California poppies, even in areas with nutrient-poor soil. The addition of chemical fertilizers can cause excess foliage growth at the expense of blooms.
California Poppy Varieties
There are several varieties of California poppies:
‘California Golden’ delivers that classic bright orange color of the flowers.‘Mission Bells’ is a mix of sherbet hues, including pink, salmon, and cream, with some semi-double blooms (blooms with extra petals).‘Golden West’ is a twist on the familiar orange bloom, as it features a darker center.
How to Grow California Poppies From Seed
Sow poppy seeds where you intend to grow them outdoors after the threat of frost has passed in your area. Press the seeds lightly into the soil, watering gently to avoid dislodging the tiny seeds. Germination should occur in about two weeks. You can distinguish germinating poppy seeds from weeds by observing the bluish-green tint of poppy foliage. Thin seedlings to about 8 inches apart.
Common Pests/Diseases
California poppies are generally healthy plants, but they are prone to diseases when grown in an environment that experiences excessive rain. Mold, mildew, and stem rot can occur in plants growing in wet areas. Although you can treat plants with fungicides, the best option is correcting the environment. Ensure that your poppies are in full sun and well-draining soil to prevent them from being waterlogged.
