The graceful star jasmine (Trachelospermum jasminoidis) enchants mainly by its numerous, star-shaped, white flowers, which stand out clearly against the strong green leaves.
With their vanilla scent, the delicate flowers of this fast-growing vine are reminiscent of those of real jasmine.
Origin and growth
The star jasmine, also known as confederate jasmine and southern jasmine, which we like to use as an ornamental plant, belongs to the genus star jasmine (Trachelospermum), and is widespread in Asia.
It belongs botanically to the dogbane family (Apocynaceae). Of the approximately 20 species, Trachelospermum jasminoides and Trachelospermum asiaticum are used worldwide as ornamental plants.
Trachelospermum jasminoides is at home in the forests of Japan and Vietnam, where the plant lives climbing on trees and forming long, woody lianas.
Leaves, Flowers, and Flowering Time
Characteristic of the star jasmine is the brilliant white, five-petaled star-shaped flowers, which appear in large numbers between April and August.
The oval, glossy green leaves turn reddish in autumn and form a striking contrast to the sea of flowers. Especially in warm, humid weather, the flowering plant also exudes a strong, vanilla-like fragrance reminiscent of true jasmine.
Is Star Jasmin Poisonous?
As a typical dogbane plant, star jasmine is unfortunately poisonous. Especially families with small children and curious pets should refrain from planting it since the strong scent tempts them to taste the plant.
But all parts of the plant contain toxins that can cause unpleasant to dangerous poisoning symptoms. In case of poisoning, you should consult a doctor or a vet.
The woody shoots, several feet long, contain a milky sap that is also poisonous and can cause swelling, redness, and even eczema if it comes into contact with the skin.
What Location is Suitable for Star Jasmine?
Star jasmine is not sufficiently hardy and should therefore not be planted out in the garden if you live in an area with cold winters.
However, the species is excellent for container culture, for example, on the terrace, balcony, conservatory, or even in the apartment. The last two options are even preferable because there the plant can remain in one and the same location all year round.
Otherwise, the vine feels particularly well in a location with these characteristics:
- Slightly sunny to semi-shady.
- No direct midday sun.
- Airy, but not drafty, and protected from the wind.
- Ideal for the west- or east-facing balcony.
- Perfect for house wall or pergola.
When looking for a location, keep in mind that star jasmine can grow several feet long very quickly and is always looking for its way up. So a sturdy climbing aid is essential for healthy growth.
What Soil Does Star Jasmine Need?
For star jasmine to thrive and bloom profusely in a container, it needs a high-quality, nutrient-rich container plant soil.
Make sure to purchase a peat-free substrate and use a humus-based one instead. This contains all the nutrients essential for flower formation.
Alternatively, however, good garden soil can also be used, provided you sterilize it in an oven or microwave before planting. Otherwise, you are likely to have nasty surprises with weeds or pests.
Mix the chosen substrate with sand or gravel to increase permeability and thus reduce the risk of waterlogging. Clay pellets or expanded clay are also good for this purpose.
If you use soil from the garden, you should also mix in mature compost or compost soil to increase the nutrient content.
Planting Star Jasmine Properly
If possible, cultivate the star jasmine in a container, as the plant is not hardy enough for cold winters. Unless the plant can remain in its location year-round, you should plan for the possibility of moving it to winter quarters.
The winter quarters should be bright and cool, but definitely frost-free. The plant pot is most easily moved with a wheeled base, which you can place under the pot at the time of planting.
Wintering at the site is also possible, provided that the plant gets proper winter protection and temperatures do not fall below 40 °F (5 °C), even in very frosty outdoor temperatures.
Pot the star jasmine as follows:
- The ideal planting time is spring.
- Use a plant pot with a drainage hole at the bottom.
- Cover the drainage hole with shards of clay or stones.
- These prevent silting and thus clogging.
- The pot should be twice as wide and deep as the root ball.
- Mix planting substrate with drainage material.
- Fill about one-third into the plant pot.
- Carefully hold the star jasmine in place.
- Fill empty spaces with the substrate.
- Insert the climbing aid.
- Lightly press down the soil.
- Water the plant vigorously.
Watering Star Jasmine
The star jasmine does not have a high water requirement. It is quite the opposite because the vine gets by with only a little moisture even during the flowering period.
Therefore, you should be very cautious about watering especially the specimens that are placed in partial shade or out of the sun. An excess of water, after all, leads to diseases and eventually to death.
Waterlogging in particular is harmful. Excess water should be removed from the planter or saucer no later than half an hour after watering.
Fertilizing Star Jasmine Properly
The star jasmine will only show its long-lasting flowering splendor if it is sufficiently supplied with the nutrients required for flower formation.
Therefore, between April and November, you should fertilize about every two weeks with a high-quality pot or flowering plant fertilizer. Administer the fertilizer preferably together with the watering water.
A slow-release fertilizer – for example, in the form of sticks or cones that you insert into the substrate in the spring – is also suitable for an adequate supply. During the winter months, however, stop fertilizing completely.
Pruning Star Jasmine Properly
Pruning the attractive vine is not absolutely necessary, but it is recommended before putting it away for the winter.
It also makes sense to regularly thin out shoots that have grown too densely, so that the plant does not become bare from the inside – especially since the flowers cannot develop properly if the growth is too dense.
Sufficient air and light are immensely important for the healthy growth of star jasmine. Therefore, set the scissors according to the following scheme:
- Pruning in the fall after flowering.
- Thinning out in spring and if necessary in summer.
- Thinning out densely grown areas
- Remove individual, very long tendrils, especially from the interior.
- Remove old inflorescences.
Be sure to use sharp scissors disinfected with a suitable agent for pruning to avoid unnecessary bruising of the star jasmine and to reduce the risk of transmission of pathogens.
You should also wear protective gloves to avoid contact with the toxic milky sap. This should also not get into your eyes under any circumstances!
Repotting Star Jasmine
Once a year you should repot the star jasmine so that the plant can sprout better in the fresh substrate and with more space and produce numerous new flowers.
Therefore, the ideal time for such a measure is early spring. If the old planter still provides enough space for the roots, you do not need to replace it with a larger one. Nevertheless, renewing the used substrate is useful.
When repotting your star jasmine, be sure to completely remove the old soil.
Propagating Star Jasmine
You can easily propagate star jasmine yourself both by seeding and vegetatively by cuttings.
You can obtain germinable seeds of the star jasmine either from your own plant or from a specialty store. Sow them in late summer, around the beginning of September, in nutrient-poor sowing soil and press them in only lightly.
Cover the seed container with a translucent lid or foil to keep the humidity high. This measure increases the germination rate and makes the young plantlets grow faster.
The plant pot belongs in a warm and bright – but not directly sunny – location around 68 to 72 °F (20 to 22 °C). Keep the substrate only slightly moist and use lukewarm water if possible.
In spring, you can transfer the young plantlets to a larger pot with a nutrient-rich substrate.
To propagate cuttings, cut shoots about 4 inches (10 cm) long from the main shoots in August – and thus after flowering. Put them in a container with a growing medium, which you cover with foil or a cut plastic bottle.
Like the seedlings, maintain the cuttings warm and slightly moist in a bright location throughout the winter. Transfer them to a larger container with the fresh, nutrient-rich substrate in the spring.
During the rooting period, however, water only sparsely and let the substrate dry out a little in between.
Overwintering Star Jasmine
Basically, star jasmine is not winter-hardy and should therefore be moved in the fall to cool and bright winter quarters about 46 to 50 °F (8 to 10 °C).
Avoid complete drying of the root ball in winter and try to keep the substrate slightly moist. However, water the plant just enough to moisten the soil a little.
Around mid-May, the vine can return to the outdoors. Since the plant can tolerate short periods of light frost down to about 40 °F (-5 °C), you can also plant it out in regions with mild winters.
In that case, however, the star jasmine needs light winter protection.
Diseases and Pests
Unfortunately, star jasmine is quite susceptible to typical pests such as aphids, spider mites, or mealybugs. Care mistakes, especially too frequent watering, but also excessive drought can also lead to problems.
Species and Varieties
The white-flowering species Trachelospermum jasminoides looks confusingly similar to the related, but yellow-flowering Asian star jasmine (Trachelospermum asiaticum). The species also have very similar needs in terms of care and location.