Ruellia - Acanthaceae - How to care for and cultivate our Ruellia

Ruellia - Acanthaceae - How to care for and cultivate our Ruellia



There Ruellia they are delightful little plants that grow almost everywhere; much appreciated for being grown in pots for their abundant and long-lasting blooms.






: Angiosperms


: Eudicotyledons


: Asteris











: see the paragraph on "Main species"


The genre Ruellia of the family ofAcanthaceae it includes plants native to Mexico and Brazil even if they are frequently found all over the world as they live in the most diverse habitats: rainforest, desert, swamp, zonetropicals, temperate zones and prairies. The fact that the genus is so cosmopolitan is attributed to the fact that the seeds are covered with hygroscopic hairs which when wet become mucilaginous. This fact makes germination and dispersal itself easier.

Most of the Ruellia they are herbaceous perennial plants, but there are shrub, arboreal and even lianose species.

A peculiarity is that in this genus there are several cleistogamous species that is to say that the flowers self-pollinate without opening even if there are many traditional cross-pollinated species.


There are numerous species in the genus Ruellia but the best known and most widespread as ornamental plants are:


The species Ruellia makoyana it is a herbaceous plant characterized by very thin stems in which lanceolate leaves, of an intense green color, velvety and with evident veins are inserted alternately.

The tubular flowers with a corolla divided into five lobes are of an intense violet color.


There Ruellia brittonianait is a perennial plant characterized by dark green leaves, opposite, lanceolate, up to 30 cm long and no more than 2 cm wide.

The flowers are blue-violet, trumpet-shaped and about 3-5 cm of diameter.

There are numerous varieties that differ in flower colors ranging from white, to pink, to different shades of blue as well as dwarf varieties.

It is a very showy plant as its flowers are highly sought after by butterflies so a cloud of butterflies is always present around them.


They are plants that are easy to grow and do not require particular cultivation measures and are also easily adaptable to different soil and climatic situations.

They are plants that must be grown in pots as they fear the cold: temperatures below 5 ° C can be fatal.

They love to be positioned in excellent light but it is preferable not to expose them to the sun directly in the hottest hours of summer days.

They are fast-growing plants for which they give a lot of satisfaction thanks also to abundant and varied blooms.

The species normally used for ornamental purposes have a climbing posture so they are particularly suitable for being bred in vasisuspended conditions.


There Ruellia it is often watered in the spring - summer period but having the foresight to let the soil dry on the surface between one irrigation and another.For these plants we keep in mind that it is better to water one less than one more as they can withstand even short periods of drought. During the autumn-winter period, watering must be significantly reduced.


There Ruellia it should be repotted every two / three years.

Use a soil rich in organic substance with the addition of a little coarse sand to favor the drainage of irrigation water as it does not tolerate water stagnation. For this purpose, it is important to place pieces of earthenware on the bottom of the vase that favor the drainage of excess watering water.

It is recommended to use terracotta pots that favor gas exchanges with the external environment by making the water evaporate more quickly, thus correcting any errors caused by excessive watering.


Starting from spring and throughout the summer it is advisable to fertilize theRuellia every 3 weeks using a good liquid fertilizer that will be administered with irrigation water. At other times of the year, they must be suspended.

It is advisable to use a fertilizer that in addition to having macroelements such as nitrogen (N), phosphorus (P), potassium (K) also contains the so-called microelements, that is to say those compounds that the plant needs in minimal quantities (but hapur always needed) such as magnesium (Mg), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), boron (B), molybdenum (Mo), all important for balanced growth of the plant.

A tip: reduce the fertilizer doses compared to those indicated in the package both because they are always exaggerated and because if; repot every 2/3 years, you will give your plant a good supply of nutrients.


It is advisable to shorten too long branches in the springRuellia in fact it tends to grow in a disorderly manner, therefore it is necessary to periodically intervene. Old or dead leaves must also be eliminated to make room for new shoots and avoid them becoming a vector of parasitic diseases.


The flowering period of the different species ofRuellia it is variable even if most of it blooms in the spring - summer period.


There Ruellia it multiplies by seed or by cutting.


In spring, cuttings about 10 cm long are taken by cutting them immediately under the node. Choose them from robust and healthy plants. It is recommended to cut obliquely as this allows for a greater surface for rooting and avoids the accumulation of water on this surface.

Use a sharp blade to avoid fraying of the fabrics and that is clean and disinfected (preferably with a flame) to avoid infecting the fabrics.

After removing the lower leaves, arrange the cuttings; in a compote formed of peat and sand in equal parts by making holes in the soil with a pencil, as many as there are Ruellia cuttings to be placed after taking care to gently compact the soil.

The box or pot is covered with a transparent plastic sheet (or a bag with a cap) and is placed in the shade and at a temperature of around 18-21 ° C. Taking care to keep the soil always slightly moist, watering without wetting the cuttings in rooting with water at room temperature. Every day the plastic is removed to check the humidity of the soil and eliminate the condensation that has surely formed from the plastic.

Once the first shoots start to appear, it means that the cutting has taken root, at which point the plastic is removed permanently and the pot is placed in a brighter area, at the same temperature and expects the cuttings to RuelliaAfter that transplant them into the final pot and treat them like adult plants.

Seed multiplication can also be adopted, which however brings with it the advantage that by taking over the genetic variability, it is not certain that plants will be identical to the mother plants. Therefore, if you want to have a precise plant or are unsure of the quality of the seed you are using, it is good to do the multiplication by cuttings.


If you plan to sow in pots or in seedbeds, the seeds should be sown in spring in a compost formed by fertile soil and coarse sand. Since the seeds are not particularly large to bury them lightly, push them under the soil using a flat piece of wood or you can pour new soil on top.

The tray containing the seeds should be kept in the shade, at a temperature of around 15 ° C. Keep the soil constantly moist using a sprayer that allows you to have a more even distribution of water, until the moment of germination.

The tray must be covered with a transparent plastic sheet (or with a glass plate) which will guarantee a good temperature and will prevent the soil from drying out too quickly. The plastic sheet must be removed every day to check the degree of humidity in the soil and remove the condensation that will surely have formed.

Once the seeds have germinated, the plastic sheet is removed permanently and the box is moved to a brighter position (not direct sun). Ruelliasurely there will be those less vigorous than others. Identify and eliminate them in this way you will give more space to the most robust newborns.Once the plants are large enough to be handled they are transplanted into single pots with a soil as indicated for adult plants and treated as such.


The plant does not bloom or produces few flowers

This symptom is attributable to a lack of light.
Remedies: place the plant in a brighter position.

Presence of small whitish animals on the plant

If you notice small white-yellowish-greenish mobile insects you are certainly in the presence of aphids or as they are commonly called lice. If you observe them with a magnifying glass and compare them with the photo on the side, you cannot fail to recognize them.

Remedies: treat the plant with systemic pesticides, that is to say that they enter the lymphatic circulation of the plant and are therefore absorbed during the nutrition of the insects, available from a good nurseryman.

Leaves that begin to turn yellow, appear mottled with yellow and brown

If the leaves show this symptom, it is most likely an infestation of red spider mite, a very annoying and harmful mite. If you look closely you can also find cobwebs.

Remedies: increase the humidity around the Ruellia ihow much the lack of humidity favors their proliferation. In case of particularly serious infestations, use a specific insecticide. If the plant is not particularly large, you can also try cleaning the leaves to mechanically eliminate the parasite using a wet and soapy cotton ball. After that the plant should be rinsed very well to get rid of all the soap.

Presence on the plant of white insects similar to small butterflies

These small insects are whiteflies, known by the common name of whiteflies. To be sure of their presence just shake the plant: if a white cloud rises, it means that they are present. They are concentrated mainly on the lower page of the leaves. The damage they cause is determined by the subtraction of the lymph thanks to their stinging-sucking mouth apparatus and by the punctures they make in the tissues for the deposition of the eggs. They also produce honeydew which is nothing more than the sugary and sticky excrements of the whiteflies which can cause the onset of fumaggini and can transmit virosis.

Remedies: treat with specific pesticides available at a good nursery.


The genus was calledRuellia in honor of Jean de la Ruelle (1474 - 1537), physician and herbalist of the French king Francis I and translator of numerous works by Dioscorides.

From some species of Ruellia herbal teas are obtained used for medicinal use for the treatment of headache, for dizziness, such as eye drops.

In English this plant is calledwild petunia "Wild petunia" ormexican petunias "Mexican petunias".

Online bibliographic sources
- Tree of Life web project

Video: Mexican Petunia - Beware Invasive Plant