Last Updated on September 16, 2022 by Plant Mom Care
Plumbago or leadwort is a genus consisting of 10–20 flowering plants, with the species belonging to the Plumbaginaceae family. Originally from South Africa but widespread now as an ornamental, it can be cultivated as an annual outdoors, or in containers as a perennial which is brought indoors in colder months.
This shrub can grow 6-10 feet high with a spread of 8-10 feet. The light green leaves are about .4 to an inch long, another noticeable feature is the copious axillary spread of leaves creating a bushy and dense appearance to the plants. The light blue flowers form on rounded clusters, plant flowers all through the year in warm climates but only in summer and autumn in cooler climates.
It is mostly cultivated in landscapes as shrubs or groundcover but is often trained to grow as low hedges with frequent pruning or trained to climb up on a trellis. It is a low-maintenance plant and drought tolerant when it becomes established.
Plumbago Light Requirements
Although this plant tolerates partially shaded conditions, it flowers more abundantly with 6+ hours of daily sunlight in hot climates than it can do with some afternoon shade during the summer.
This plant should be watered consistently when first planted through its first season, but once it gets established it will become drought-tolerant and needs water once weekly. Container plants need moderate watering as they are vulnerable to root rot. Plants in cold climates that are brought indoors in winter need less watering.
This plant enjoys high humidity and does well in climates with naturally moist air. This is a good plant to grow in warm and humid locations. It can tolerate average levels of humidity through flowering.
When growing it indoors in containers, sunrooms or bright window sills will make good spots to keep the plant in with frequent misting. If you have many humidity-loving plants growing indoors, grouping them near a humidifier will help keep humidity consistent as dry air conditions will cause damage. Keep the plant away from cold or hot vents which can dry the plant out.
This plant prefers somewhat warm temperatures as it is at risk and will suffer damage in temperatures below 32°F. They might wilt under very hot conditions but will bounce back when the temperature cools. Protect it from the hot afternoon sun if you live in very hot climates.
A mulch layer is necessary to protect the plant’s roots when growing outdoors in winter – it will typically die back but growth will resume in spring. Make sure you remove the mulch in spring as new growth starts. Generally, this plant can thrive in zones 8b to 11.
This plant is tolerant of most soil types such as sandy, loamy or clayey soils, provided the soil has good drainage capacity. It likes somewhat acidic soil pH but can grow in neutral and somewhat alkaline soils too.
To repot this plant, ease it from its current home and loosen the roots to allow old soil to fall away without injuring the root system. Select another container 1 or 2 sizes bigger than the old one and fill the bottom third with well-draining soil amended with sand to increase drainage capacity. Place it on the layer of soil and pack in more soil to completely cover the roots. Give it a good watering and resume care as normal.
While the plant does make seeds, the seedlings will take 2 or more years to flower and up to 4 weeks to germinate under specific requirements. That said, this plant is generally and easily propagated from wood cuttings, so you can harvest cuttings from an existing plant in your garden and propagate several new plants to spread around your garden to give to family and friends.
A four or five-inch cutting taken from a woody stem is needed to propagate the plant. Clip it at a 45° angle from the stem to create an extra surface area from where the roots will grow. Dip the end into rooting powder/liquid and plant into a small container of potting soil.
Keep the soil constantly damp without water-logging it and place the cutting in a shady area. Propagate this plant in summer when the weather is ordinarily warmer.
The cutting will start forming a root system within four weeks – you can tell if roots have formed if you carefully tug on the cutting and find some resistance. Once the roots have taken and new growth starts emerging, they can be transferred to a large container and allowed to grow to a good size. Now you can decide where you want it to be placed permanently – in your garden or as a potted plant.
Provide the plant with a high potassium content fertilizer during its growing season to help it constantly produce flowers. Also, consider adding phosphorus to help strengthen the root system to ensure good long-term health.
Pruning is necessary to keep this plant’s growth under control as it grows rapidly and spreads if left unattended. The advantage of growing this plant is that it’s relatively easy to be trained into hedges, or a shrub, as ground cover, or trained to climb up on a trellis. Frequent pruning is necessary for plants grown in containers.
Pruning will also help encourage more blooms. Plants growing in cool climates have to be radically cut down to the soil in late winter and protected from frost until the weather becomes warmer.
Plumbago Common Problems
This plant can resist most diseases and pests, but it is prone to whitefly infestation. Severe infestations can make leaves brown, shrivel and fall as these pests suck on the leaves to extract sap and weaken the plant. Pruning away infested foliage or spraying the leaves instead of using insecticides is preferable. This plant is also prone to attacks from spider mites, although the damage is not as severe.
Transplant shock often causes dead flowers and wilting a few days from transplanting or repotting. Pruning dead flowers and foliage will reduce stress, allowing the plant to focus energy towards developing a healthy root system.
Frost can kill the foliage on these plants, but if you live within its tolerable hardiness zones, the roots usually survive the winter. When this happens, wait for late winter before pruning dead foliage for healthy growth. As mentioned, it might have to be pruned drastically, but new shoots will emerge in spring if the roots are protected and survive.