This hardy shrub features masses of dainty-looking, intense blue flowers on slender stems with pale green leaves. It will bloom all year round in warmer climates. It’s a gardener’s dream for anyone living in a mild and sunny environment as the Blue Plumbago is easy to care for, grows quickly, and attracts an array of birds and wildlife, including butterflies, which are drawn to the scent of the flowers.
The Blue Plumbago is also incredibly versatile and can be used as ground cover, hedging, a climber on supports or trellis, as a container plant, or cascading down from a hanging basket. Added to this, the plant is relatively pest-free, disease-resistant, and deer-resistant. Established Blue Plumbagos are drought-tolerant but not frost-tolerant. In low temperatures, the plant will die or need to be brought inside for protection against cold winters.
Blue Plumbago Overview
Blue Plumbago Quick Facts
|Scientific Name||Plumbago auriculata / Plumbago capensis|
|Type||Annual or perennial evergreen shrub|
|Common Names||Blue Plumbago, Cape Leadwort, Cape Plumbago, Sky Flower|
|Ideal Temperature||60-80° F|
|Toxicity||Toxic to people, non-toxic to animals|
|Humidity||Moderate to high humidity|
Caring for Your Blue Plumbago
This plant enjoys a good watering and can be watered freely throughout spring and summer when it can grow at quite a fast pace. The position of your Blue Plumbago will largely dictate how much you need to water it. When grown outside in its ideal warm climate in a position of full sun, the plant will need more water. Shaded plants, or those kept in slightly cooler temperatures will not require as much water.
Plumbagos can also be grown in containers, and these will need to be watered with more care than those growing directly in the ground. This is because plants growing in ground soil have more options available to them than container plants. Plumbagos planted in the ground can spread their roots further in search of moisture, while those grown in containers are confined to their space and therefore rely on you to supply them with adequate water.
Equally, container plants are more susceptible to root rot than those grown in the ground, as the soil holds on to moisture, with only the drainage holes for it to escape from, rather than having the depths of the ground to drain water away. For these reasons, Blue Plumbago grown in containers will need their watering schedule adjusted accordingly. Aim to keep their soil moist but not wet. That being said, established Plumbagos are fairly drought-resistant and will tolerate some neglect.
Blue Plumbagos, in general, are one of the easiest plants to grow, provided they are in warm temperatures, so don’t worry excessively about your watering schedule, with a thorough watering once a week during summer being perfectly acceptable. If your plant becomes dormant or grows very minimally over winter, you will need to greatly reduce watering or stop watering it altogether.
The Blue Plumbago plant was originally discovered in the hot environment of South Africa and has since been introduced to mild climates around the world, including Florida, Texas, California, Australia, and Spain(University of Florida- Institute for Food and Agricultural Sciences- Gardening Solutions).
If you live in an area which is mild all year round, then this is the ideal growing environment for this plant. In warm temperatures, it is able to flower all year round. It can be grown in slightly cooler climates but will die off over winter and need to be cut right back to ground level, or if kept in a container, it can be brought inside throughout winter to avoid frost. The lowest temperature this plant can tolerate is around 32° F, so make preparations to protect your plant or winter it inside if your local climate typically drops below this over winter. In spring, the Blue Plumbago planted in the ground will usually come back to life and continue with its impressive growth. Container plants can be cut back before being moved back outside in warmer weather to stimulate growth.
As a native of South Africa, this plant is accustomed to a warm and bright climate. If kept outside, it will need to live in a spot with plenty of direct sunlight in order for it to really flourish. It will tolerate growing in shade, but this will come at the expense of flower production. If kept indoors, it will do best in the full sun of a conservatory or sunroom, or on a bright windowsill.
This plant loves high humidity and will do very well in climates which have naturally moist air. If you live in a warm and humid environment that enjoys a mild temperature all year round, then this is a great plant to have. It will tolerate moderate humidity though may lack some blooms as a result. Blue Plumbago plants grown in glasshouses, sunrooms, conservatories, or on bright windowsills, will benefit from frequent water mistings to keep the humidity up. If you have several humidity-loving plants in one room, then an electric humidifier might be useful to consistently keep humidity high without you having to make a continued effort.
Dry air will damage this plant, so if it is kept indoors, be sure to keep it away from heating vents, stoves, or any other items which could dry out the plant.
Blue Plumbago plants will benefit from a regular application of fertilizer during growing seasons. A fertilizer high in potassium will result in an abundance of lush flowers, while phosphorus will help the plant to develop a good root system, which is important for its overall growth and long-term health. The type of fertilizer you choose really comes down to personal preference.
If you prefer to feed your plants only occasionally and not have to worry about a frequent feeding schedule, then slow release fertilizer could be the best option for you. There are many types of fertilizer on the market to suit everyone’s budgets and requirements. You can be quite specific about the fertilizer you use on your plant, doing in-depth research to find the ideal proportions of nutrients, or you can buy a general all-purpose fertilizer. Go with whatever works best for your situation; just ensure that you are following the instructions on the bottle and getting your Plumbago the nutrients it needs.
The Blue Plumbago plant is a rapid grower, and, as such, will need to be kept in check with regular pruning if you don’t want it to get out of control. Without proper attention, the plant can grow in excess of ten feet tall and ten feet wide.
How you go about pruning your plant will depend on the type of style you are trying to achieve. While the Blue Plumbago is technically categorized as a shrub, it is most often used as a climber or trailing plant. It can also be very effectively used to create hedging. Pruning will also result in more blooms when you cut it back during its growing period, as flowers appear on the ends of new growth, so you can cut back your plant in an effort to encourage more flower production.
If you need to fill in space among your flower beds, plant the Blue Plumbago directly in the ground and allow it to spread. It will quickly cover ground and should be pruned back to prevent it from encroaching on other plants. With some encouragement in the right direction, it can fill vacant space very well.
When kept as a climbing plant it will need help from a trellis. If you are trying to get it to cover a particular space, you will need to guide it and prune it back where necessary. As a climber, it will grow rapidly and can become out of control easily if not pruned and tamed.
The Blue Plumbago also works well as a trailing plant, dripping out of the sides of hanging baskets. When used like this, the plant will need a lot of pruning to keep it looking neat; otherwise, it will become messy and unkempt.
The plant can be grown in a container and kept in pretty much any shape you wish. If heavily pruned, it will take the form of a shrub, but to achieve this might require heavy maintenance as the quick growing stems can easily become straggly. Once the Plumbago is happily growing as a shrub, you can prune it into your desired shape, and you will be rewarded with plentiful flowers on the cut ends, resulting in a very attractive feature plant.
As warm temperatures come to an end when autumn approaches, you will need to prune the Blue Plumbago right back to just an inch or two from the ground. If grown in soil outside, you can cover it to protect it from frost, and it will become dormant over winter. Remove the cover when mild temperatures return, and the plant will spring back to life over the course of a few weeks, becoming a rapidly growing plant again by summertime. If your Plumbago is kept outside in a container, then you have two options when the cooler months arrive. You can prune it right back to ground level and bring it inside to an area that is dark but not excessively cold. A basement or garage would be ideal.
At this point, some people cover the plant up, but this is really a personal preference and isn’t entirely necessary if the room is already dark. This process will allow the plant to become dormant and rest over winter, and you can take it back outside and resume normal care in springtime. Alternatively, if you have the space, you can bring the plant into your home to enjoy throughout fall and winter.
If it has been allowed to grow throughout spring and summer, then it will likely need heavily pruning in order to make it a manageable size to bring inside. As the plant will likely not grow much more once you bring it inside, don’t prune it severely; otherwise, it may not look very pleasant to keep in your home throughout winter. Cut it to an acceptable size and move it to a warm and bright spot inside, such as on a windowsill or in a sunroom. Don’t worry if you do over prune, as the plant will recover well in spring and continue growth.
If your Blue Plumbago lives in a container, you will need to repot it every two to three years. The plant grows rapidly and can quite quickly fill its pot with roots and become root-bound. In order to allow your plant to stay healthy and continue to grow year after year, repot it when it is struggling for space in its container.
The best time to do this is either at the beginning of spring before you move the Blue Plumbago back outside, or in early autumn when you bring the plant inside to overwinter it. At both of these times, the plant should have been cut back and will be small enough to make handling much easier. To see if your plant requires repotting, firmly hold the base of the plant and gently tug until the root ball and its soil comes loose from the pot. You should quickly be able to see how condensed the roots are and if they need more space. If you are unable to remove the plant from its container with ease, then this is probably because the roots are so tightly packed that they have become jammed in the pot, and is a definite sign that you should repot your plant.
To repot the Blue Plumbago, gently remove it from its current container and rub the roots between your fingers to loosen them and allow any of the old soil to break free and be removed. Remove as much old soil as you can without harming the root structure. Select a new container one or two sizes bigger than the current one and fill the bottom with a well-draining soil, ideally with some sand mixed in to increase drainage efficiency. Place the root ball of your plant on top of the soil, then gently pack more soil in all around the edges. The plant should sit at the sand height in the pot as it did in its last pot. Water the plant heavily and then continue care as normal.
The Blue Plumbago plant can be easily propagated using wood cuttings, so if you already have one of these plants, then you could also have an endless supply of new Blue Plumbagos to have in different areas or to gift to friends.
To propagate, you will need around a four or five-inch stem cutting from a woody part of the plant. Cut it from the mother plant using sharp shears at a 45-degree angle, creating more surface area from which roots can grow. Dip the cut end of the stem in rooting hormone to encourage the cutting to develop roots, and plant it into a small pot filled with potting soil. Keep the soil continually moist without allowing it to become wet, and place it in a shaded area. Heating the cutting from underneath will help roots to develop, though it is best to propagate this plant in the summer when temperatures are ordinarily higher.
Within four weeks your cutting should have the early stages of a root system. You will know if roots have developed if you gently tug on the cutting and feel some resistance. If the cutting can be easily pulled from the soil, then it doesn't yet have roots. Once you have evidence of roots, you can transplant the cutting to a bigger pot and let it grow into a new Blue Plumbago in its own right. When the plant reaches a good size, it can be transferred to a more permanent spot, either directly in the ground or into a container.
All elements of this plant are toxic to humans, including the sap, fruit, pollen, seeds, bark, roots, and foliage (Gardeners World). When handling the plant, you should always wear protective gloves and have your arms covered with long-sleeved clothing. Try to keep your face away from the plant and consider wearing protective eyewear. If the toxins come into contact with the skin or eyes, you can expect to suffer from irritation and blistering. It is also harmful if ingested, potentially causing vomiting and an upset stomach.
Interestingly, the plant is not reported to be toxic to animals, so while you might want to keep your distance from the Blue Plumbago, you can allow your pets to roam freely near it. Take particular care to keep this plant away from children.
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