Romneya coulteri

The Romneya coulteri is a spectacular perennial bush forming a large, bushy and creeping mass covered in summer with very white poppies with golden yellow centers, it carries the evocative name of Tree Poppy. Its vegetation, which can reach gigantic proportions in favorable conditions, is more or less evergreen depending on the climate. Its stems are adorned with a very beautiful gray-blue cut foliage. It reveals all its splendor in summer, when its large, delicate crepe-like flowers appear, with a pleasant lemon scent. Sometimes considered capricious, it will make the pride of the gardener who will see it grow and beautify year after year. Offer this host of Californian scrub vegetation the foot of a wall, or sun-crushed slope, but don't forget watering and fertilizing!

The Tree Poppy is a perennial plant with a woody stump belonging, like our poppies, to the Papaveraceae family. It originates from rocky slopes and arid ravines in southern California. It is found in dry chaparral, a semi-arid vegetation formation comparable to our scrublands and maquis, as well as along the sparsely watered Californian coasts. The vigorous stump spreads through powerful underground rhizomes that can reach over 1m (3ft) in length and become invasive if the conditions are right. An adult plant will reach a height of 1.50m (5ft), but will spread indefinitely over time. Some subjects colonizing more than 25m² have been observed in Californian gardens! The spectacular flowering is at its peak in May-June in mild climates, and can continue until September. The flowers, pleasantly fragrant, are in the form of huge poppies measuring 15 to 20cm (6 to 8in) in diameter. They are composed of 6 crumpled petals of a silvery-white colour surrounding a prominent center composed of numerous yellow-orange stamens. They are followed by the formation of curious and decorative fruits in dry bouquets, resembling small cages in structure. The foliage is more or less evergreen depending on the severity of the winter. It consists of tough leaves, 12cm (5in) long, irregularly divided into 3 to 5 lanceolate lobes, of a beautiful gray-blue colour. The Romneya coulteri is a plant linked to fire ecology; seed dormancy will only be lifted in the presence of smoke. Its multiplication is delicate, its cultivation requires a certain skill, which explains the relative rarity of this plant in cultivation.

The Romneya coulteri is a highly desirable plant, but delicate to cultivate and not very resistant to heavy frosts (up to -10/-15°C (14/5°F) nevertheless in dry soil). The most beautiful specimens in France grow in the southern half of our country, in poor, light, and dry soil in summer. Its beauty and its requirements in terms of sun and heat require it to be installed in isolation on a large slope, or at the foot of a fence. It will thrive where the Fremontodendron californicum, the evergreen ceanothus, its perennial cousin Eschscholtzia californica, the Callirhoe involucrata (the mauve poppy), and our Mediterranean caper all thrive. One could imagine gathering all these plants in a large raised bed, enriched with coarse sand and gravel.