Plumbago

( plum - BAY - goh )

At-A-Glance Information

This genus of evergreen and semi-evergreen shrubs includes species that need full sun to light shade and little to regular water for best performance in the landscape. Plumbago plants are commonly called Leadwort, and produce flowers that will attract butterflies and other pollinators to the garden. They plants have a sprawling habit and bloom over a long season in spring and summertime. Flowers can be blue or white and appear in clusters at branch tips. Use Plumbago as ground cover or erosion control in sloped areas of the landscape, to add lush foliage to drought-tolerant mixed beds and borders, or as members of pollinator, seaside, or rock gardens. They can make handsome informal hedges and screening plants, and can also be trained to grow up trellises or walls. Take care when planting these shrubs in the landscape, as contact with some species can cause dermatitis and ingestion of plant parts is toxic to humans and animals.

Plumbago Species and Varietals

The genus Plumbago includes 23 species and is the type genus member of the plant family Plumbaginaceae. The plants in this genus are closely related to those in Ceratostigma (Leadwort), Limonium (Sea Lavender) and Armeria (Thrift). The best growing zones for Plumbago vary depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Plumbago auriculata (Plumbago capensis) (Cape Plumbago, Sky Flower, Cape Leadwort, Blue Plumbago)
This species of Plumbago can be evergreen or semi-evergreen, depending on the climate. They do well in USDA hardiness zones 8-11 or Sunset growing zones 8, 9, 12-24, H1 and H2, and are native to South Africa. it forms a mounding shrub 6 feet tall and 8-10 feet wide. If given adequate support, this species can reach 12 feet or more as a vine. Flower color varies from white to blue. Not fussy about soil but needs good drainage to perform well. Use as a cover for banks, fences, or walls or as a background or filler plant in the landscape. Choice varieties include 'Royal Cape', 'Imperial Bliue' or Plumbago auriculata alba (with white flowers). This species is considered invasive in Hawai'i, coastal Australia, and Cuba.

Plumbago europaea (Common Leadwort, Denallaria, European Leadwort)
Native to the Mediterranean Basin and Central Asia, this perennial species reaches up to just over three feet tall at maturity and produces green foliage. Flowers are typically light purple-pink with darker central lines on each petal. Flowers bloom on this species around September each year. Common Leadwort grows well in USDA hardiness zones 7-10.

Plumbago indica (Indian Leadwort, Scarlet Leadwort, Whorled Plantain, Rose-Colored Leadwort, Chitraka, Red Plumbago, 紫花丹)
These plants are native to Southeast Asia, Indonesia, the Philippines, and southern China and grow well in USDA hardiness zones 8a-11. They can reach up to 7 feet tall by 3 feet wide at maturity, and produce green foliage and deep pink to scarlet colored flowers. These are prized as garden ornamentals for their showy flowers, and are hardy down to 45 degrees Fahrenheit.

Plumbago scandens (Plumbago zeylanica) (Doctorbush, White Plumbago, Summer Snow Plumbago, Ceylon Leadwort)
This evergreen species grows well in USDA hardiness zones 8b-11b or Sunset growing zones 12, 13, 21-24, H1 and H2 and is native to a region that spans Florida through Arizona and down through Central America. New leaves are deep red, and mature to medium green. All foliage turns red in late fall and winter. Flowers bloom year-round with a short break during the warmest parts of the summer. Blooms are typically white, though they can be blue. Hard prune to control size and encourage colorful new foliage. Good in most soils but can suffer from powdery mildew in summer. Can serve as a large-scale groundcover. Cultivar 'Summer Snow' has flowers that are pure white.

Caring for plumbago

Take care when planting these shrubs in the landscape, as contact with some species can cause dermatitis and ingestion of plant parts is toxic to humans and animals. Always wear gloves when pruning or handling plant parts. Space plants 3 feet apart for a dense, overlapping hedge or privacy screen. When planting in mixed beds and borders or as an informal hedge, space plants 4 to 5 feet apart. Groundcover varieties should be spaced between 12 and 18 inches apart. Plumbago shrubs thrive in full sun to partial shade; the more sun they get the more they will flower. They appreciate between 6 and 8 hours of sun in most cases, but in particularly warm or dry climates appreciate afternoon shade to protect petals from burning and bleaching. 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. These shrubs prefer regular waterings that keep the soil consistently moist, but not soggy. Provide established plants with deep waterings that will encourage the root system to reach deeper into the soil. Reduce waterings in fall and wintertime when the plant is in its dormant stage.

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. Plumbago should be pruned back hard in late winter to control growth and keep a compact, bushy look. Remove any dead, damaged or diseased branches, and then cut 1/3 of the plant's thickest, oldest, or leggiest stems back to 6-8 inches. Note that on some Plumbago species there is a material on the undersides of leaves that looks very similar to powdery mildew. This is actually just a chalky substance secreted by the leaves, and is no cause for concern. Tip prune the remaining stems by 4-6 inches, making clean cuts just above an outward-facing bud. This will encourage dense, lateral branching and more flowers to form. Plumbago shrubs bloom on new wood (the current season's growth). They can be trained to grow as climbing vine when manually tied up, and into a patio tree if pruned and trained from a young age. In cooler climates, provide winter protection to avoid frost damage (especially for younger or newly installed plants). These shrubs are able to persist in the landscape for decades when grown in tropical or warm climates and properly cared for.

Caring for Plumbago in Containers
These shrubs can be grown in containers, where they spill over and can be trained to climb, making them a perfect, fast-growing screen for balconies and patios that need privacy. Growing Plumbago in containers also means that they can be moved into a sheltered, warm spot over the winter months, allowing gardeners in more temperate zones to keep them as perennials. Choose a container that is at least a few inches wider and deeper than the nursery pot or root ball. Ensure that the pot has adequate drainage holes on the bottom to allow for excess water to flow away. Fill with a well-draining potting mix amended with organic material and perlite, and top with a layer of mulch to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water regularly as the plant establishes itself in its new home. Once established, waterings can be lessened. Plumbago plants grown in containers will need more frequent irrigation than those grown in the ground. As a general rule of thumb, water whenever the top few inches of soil feels dry to the touch. Prune to remove dead, damaged, or diseased foliage at any time during the growing season. Every few years, check the bottom of the pot to ensure that the plant is not outgrowing its root space. If roots are growing through the drainage holes in the bottom of the container, it is a good indication that it needs to be potted up; choose a slightly larger container and repot.

Propagation

Plumbago can be propagated either by using 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 Plumbago 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 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. Always wear gloves when pruning or handling plant parts, as contact with sap can cause dermatitis. Cut one or more 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 to six weeks have passed, your cutting should be rooted. When you notice new growth, 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 shrub.

Propagating Plumbago 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.
Harvest your seeds. The seed pods are pretty easy to spot, left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your 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 7-10 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
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. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Plumbago plants produce small, dry, oblong capsules that contain one seed each.

Plumbago seeds are light and have a sticky outer calyx that serves to attach them to the fur and clothing of passers-by.

Problems and Pests

Certain Plumbago species are considered invasive in some regions; see the species descriptions above for more information. Check with local authorities before planting. Plumbago shrubs are susceptible to the following issues: