Romneya

( ROM - nee - uh )

At-A-Glance Information

This shrubby perennial is commonly called Coulter's Matilija Poppy, Fried Egg Plant or California Tree Poppy and needs full sun and little to moderate water to perform well in the garden. These plants are native to the coastal mountains and valleys of Southern California and Baja California, Mexico, and reach 6-8 feet tall when mature and in bloom. Leaves are grey-green and large flowers are white with gold centers. These shrubs are great for hillsides, sloped areas and in marginal areas or wide borders, and produce some of the largest flowers of all California native plants. The genus Romneya, named for Irish astronomer John Thomas Romney Robinson includes just two species, and is a member of the plant family Papaveraceae. California Tree Poppy grows well in USDA hardiness zones 8-10 or Sunset growing zones 4-12, 14-24 and H1 (to find your zone, click here: Zone Map).

Caring for romneya

Romneya is typically grown in the ground; containers can restrict their underground rhizomes and plants often produce fewer flowers. They transplant poorly, and are most commonly grown from seed direct-sown into the garden. Plant Romneya in full sun (at least 6 hours of direct sun each day is ideal) in well-draining soil that is acidic to slightly alkaline (with a pH of between 5.0 and 8.0). Ensure that soil is well-draining, rich in nutrients, and has a pH of between 6.0 and 7.0 (slightly acidic to neutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water regularly during the growing season and while the plant is getting established in its new home. At maturity, these shrubs are considered drought-tolerant, but do like deep waterings during the warmer months of the year during extended dry weather.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. Prune to maintain shape and remove dead foliage or branches and spent flowers in late springtime. If the plant needs a rejuvenation pruning, in fall cut the whole plant nearly to the ground; new shoots will start to emerge in late wintertime and the shrub will bounce back completely in springtime. These flowering shrubs can survive in the landscape for about 20 years before needing to be replaced.

Propagation

Romneya can be propagated either by using root cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your shrub, follow the instructions below:

Propagating Romneya by Root Cutting
Root cutting should be attempted only when the plant is not in its active growth period; ideally, December through February. To use this method, you will need a clean shovel, clean pruning saw, extra pots, and well-draining soil to fill the pots. To propagate your shrub by root cutting, follow the instructions below:

Identify the plant you're going to take your root cutting from. Ensure that the plant has had a good watering the night before, as this will increase the odds that your root cutting will take. Start by loosening the soil around the plant with a shovel, working your way inward to avoid causing damage to the roots. Once you've gotten the clump out of the ground, lay it out on its side.
Identify a root (or a few roots, if the plant is large) that you'd like to use. The root should have at least 4-5 nodes on it. Lay them out on the ground. Then, cut the root segments into 6 to 9 inch pieces, with the nodes in the center of the pieces.
Place cuttings horizontally a few inches below the soil surface. Water generously and ensure that adequate drainage is occurring.

Propagating Romneya by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Romneya seeds have a fire-and-smoke dormancy that needs to be broken in order for germination to occur. To mimic these conditions, soak the seeds in smoke water or wood vinegar for 24 hours in late fall before sowing. If this treatment fails to break dormancy, seeds may also need a period of cold stratification. To complete this process, place seeds in a bag or other sealable container filled with moistened sand or peat moss. Then, place the container in the refrigerator (or similarly cool, dark space) for 4-8 weeks. The ideal temperature for cold-stratification is around 35 degrees Fahrenheit.

Water a prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place seeds on top of the soil surface and cover them with a light dusting of soil. Water with a spray bottle. Place the tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 4 to 12 weeks from sowing.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Plant the shrub out in the landscape when it has its first few sets of true leaves. These plants do not transplant well, so the earlier on they can be planted out in the landscape the better.