Ceratostigma
( ser - at - oh - STIG - muh )
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At-A-Glance InformationCeratostigma, also known as Plumbago or Leadwort, is a group of evergreen and deciduous shrubs and perennial flowers. They need full sun to partial shade (depending on the species) and moderate to regular waterings to perform well in the garden. They are generally low-growing plants with blue to purple flowers appearing in summer and late fall. The flowers will attract hummingbirds and butterflies to your garden. This genus is distinct from the genus Plumbago (although they are related). Use these plants as groundcovers, in mixed beds and borders, or in containers on patios or walkways.
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Ceratostigma Species and Varietals
The genus Ceratostigma includes eight distinct species, and is a member of the family Plumbaginaceae. Plumbago growing zones depend on the species cultivated; see the below descriptions for more information. To find your zone, click here: Zone Map.
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Ceratostigma griffithii (Burmese Plumbago, Griffith's Plumbago, Griffith's Blue Leadwort) This is an evergreen shrub that grows best in USDA hardiness zones 7-10b or Sunset growing zones 4-9 and 14-24. Native to the Himalayas, this plant grows to 2.5-3 feet tall and wide. Hardy, but the leaves can be damaged by frost. |
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Ceratostigma plumbaginoides (Plumbago larpentae) (Dwarf Plumbago) This is a perennial groundcover native to China. Individual plants get to be 8-16 inches tall at maturity and should be planted about 1.5 feet apart for good coverage. Bronzy, dark green leaves will turn reddish brown with frost. Spreading occurs through underground stems. Grows in USDA hardiness zones 5-9 or Sunset growing zones 2b-10, and 14-24. |
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Ceratostigma willmottianum (Chinese Plumbago) This species grows best in USDA hardiness zones 6-9 or Sunset growing zones 4-9 and 14-24 and is deciduous. It forms an airy mass of wiry stems about 2-4 feet tall and wide at maturity. Leaves are a deep green color and somewhat diamond-shaped, and turn yellow or red and drop quickly after frost. |
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Caring for ceratostigma
Ceratostigma, or Plumbago, should be installed in a space in the landscape that receives full sun to partial shade. Ideally, they like to get between 6 and 8 hours of sun each day, though they appreciate some late afternoon shade in warmer climates. Grow Plumbago in medium, well-draining soils that are slightly acidic to neutral (with a pH of between 6.1 and 7.8). Ensure that soil is well-draining and moderately fertile. 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 new plantings regularly as they establish a strong root system in their new home. At maturity, they like to have their soil dry out completely in between waterings. In general, they require about an inch of water each week.
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. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season, and remove spent flower spikes to neaten up the appearance of plants and encourage reblooms. Groundcover areas can be mowed in springtime to remove the previous years' dead stems and encourage vigorous new growth. At the end of the growing season, these plants will typically die back; they are a bit slow to leaf out in springtime as well, and some gardeners will find it helpful to mark the location of plants so they will not be disturbed by garden maintenance activities. These plants are considered perennials, typically living for between 5 and 10 years before needing to be replaced. They will spread on their own, however, providing plants indefinitely.
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. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season, and remove spent flower spikes to neaten up the appearance of plants and encourage reblooms. Groundcover areas can be mowed in springtime to remove the previous years' dead stems and encourage vigorous new growth. At the end of the growing season, these plants will typically die back; they are a bit slow to leaf out in springtime as well, and some gardeners will find it helpful to mark the location of plants so they will not be disturbed by garden maintenance activities. These plants are considered perennials, typically living for between 5 and 10 years before needing to be replaced. They will spread on their own, however, providing plants indefinitely.
Propagation
Ceratostigma, or Leadwort, for the most part will spread by itself, and sections can be dug up and replanted elsewhere if desired. Leadwort can also be propagated intentionally via cutting. To complete this process, follow the steps below:
Propagating Ceratostigma by Cutting
Propagating Ceratostigma by Cutting
- Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good substrate for propagation of cuttings 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.
- In late spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 3-6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
- Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four weeks have passed, your cutting should be rooted. When you notice new growth on your propagated Leadwort, you'll know you have roots.
- Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new plant.
Problems and Pests
Leadwort is considered generally pest and disease-free in the landscape, though it can sometimes suffer from:
- Honey Fungus
- Powdery Mildew
Gallery
Leadwort is a fast-growing, easy-care groundcover that provides both foliage and flower interest.
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Ceratostigma can grow in a number of somewhat harsh conditions, including amongst rocks in retaining walls, which softens their appearance.
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Plumbago flowers stand out against the red foliage on plants in cooler weather.
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Videos
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How to grow and care for Ceratostigma.
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All about Leadwort.
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 232, Ceratostigma
