Lycianthes rantonnetii, also known as Solanum rantonnetii, regionally also known as potato flower, potato tree or even better gentian shrub, is one of the most beautiful ornamental shrubs that a hobby gardener can grow in a pot. It immediately catches the eye with its lush and tireless bloom, which starts its breathtaking spectacle in late spring and only finishes in late autumn. The gentian shrub is not as demanding as it first appears, so year after year you will have no problem enjoying its elegant blue-purple or white-colored, star-shaped flowers with bright yellow stamens. In order for this ornamental shrub to feel at home in your own garden, you should still make sure that you meet its care requirements. Today we share them with you!
The perfect container plant for summer balconies and hobby gardens
The gentian shrub – an ornamental shrub to fall in love with
It is not for nothing that the gentian bush has the alternative name potato tree. This ornamental plant is part of the genus Lycianthes, which in turn belongs to the nightshade family (Solanaceae). It is therefore closely related to useful plants such as potatoes, tomatoes and peppers, but also ornamental plants such as petunias, angel’s trumpets and Chinese lanterns.
The flowers of the gentian bush are almost identical to those of the potato plant. If you place two freshly picked flower heads of the two plants next to each other, it is difficult to tell them apart.
Here is the well-known flower of the common potato plant
The biggest difference is the growth habit. Potato plants usually grow bushy to a maximum height of 60 cm. The gentian bush, on the other hand, grows as a shrub and can reach a height of over 2 meters under ideal living conditions. Most of the time, the ornamental plant is formed into a tall stem with precise trimming during its active growing season.
This high standard is pleasing to the eye all summer long
However, it is absolutely unsuitable for families with small children or pets
The entire plant is extremely poisonous to humans and animals
The perfect location
Today, the gentian shrub is widespread as a dainty pot or garden plant practically all over the world. Originally, however, it comes from the tropical and humid regions of South America, more precisely from Brazil, Argentina, Bolivia and Paraguay.
In our domestic hobby gardens, the gentian shrub only thrives in tubs. Only when the temperature rises above 10 degrees can he go outside, either on the balcony, the terrace or in the garden.
Choose the location carefully. These ornamental shrubs need a lot of warmth and do best in full sun. If necessary, you can also stand in the light semi-shade and still show off your wonderful flowers. However, they do not tolerate cold feet, drafts and full shade at all and immediately lose their flowering power.
As soon as the temperature drops below 10 degrees again, the pot should be back inside or in a warm greenhouse.
Most tropical ornamental plants are very sensitive to cold
This South American shrub is no exception
The right substrate
This standard has some special requirements with regard to its location. However, it is significantly less demanding in terms of the substrate.
The gentian shrub thrives best in nutrient-rich, humus-rich, permeable and peat-free potting soil that has been previously enriched with either mature compost or worm castings. A neutral to slightly alkaline pH between 6.6 and 7.8 is good for this ornamental plant.
Before you buy, be sure to pay attention to these values in the product description. If you prefer to mix your own substrate, just do a quick soil test.
Always buy peat-free soil, as this protects the moors
Do you have your own composter or worm box in the garden?
The water requirements of this ornamental shrub can vary greatly depending on the weather, location and the size of the plant itself. As a rule of thumb, the substrate should never dry out completely, especially during the active growing season and summer flowering phase. At the same time, you should not flood the roots, otherwise they can quickly rot.
You can easily test the water content with a quick thumb test. It is best to use lukewarm, stale tap water or, even better, rainwater for watering. To reduce evaporation in midsummer, you can cover the topsoil with a good layer of bark mulch. This provides additional nutrients and improves the water balance in the soil.
Rain barrels reduce your monthly water costs and are good for the environment
Fertilize gentian bush
If you have planted your gentian shrub in a good substrate that you have previously enriched with organic fertilizers, then it will not need any additional feeding in the first year, and usually not in the second year either.
From the third year, however, this high standard can certainly benefit from regular fertilization, from the beginning of March to the end of September.
On the one hand, you can add liquid complete fertilizer for flowering plants to the irrigation water once a week. Alternatively, you can only use a balanced slow-release fertilizer twice a year. Occasional watering with homemade compost tea or worm tea can also boost flowering.
Always use organic fertilizers whenever possible
Trim tall stems correctly
With proper care and optimal living conditions, this standard grows extremely fast. Therefore, if you don’t trim it regularly and properly, its crown can quickly become out of shape.
The gentian bush tolerates a strong pruning quite well. This should preferably be done in spring during the active growth phase. Shorten the young shoots by about half. If the crown starts to get too big, you can also cut back the old branches.
Even during the flowering phase, this ornamental shrub can benefit from an occasional pruning. Simply pluck off the withered flower heads. This way, your standard stem not only looks well cared for, but is also stimulated to produce more and more flowers.
This tropical tall tree absolutely needs a support
Whether on the balcony, in the garden or next to a sunny living room window – the gentian shrub always cuts a fine figure. Its vibrant blooms will decorate your indoor and outdoor spaces all summer long. We hope that our care tips will be helpful to you.