Catharanthus - Apocynaceae - How to care for and grow Catharanthus plants
HOW TO GROW AND CARE FOR OUR PLANTS
The Catharanthus, the periwinkles of Madagascar, are widely used to create hedges and beautify gardens thanks to their very long flowering that lasted from spring to late autumn.
Species: see the paragraph on "Main species"
The genre Catharanthus of the family of Apocynaceae it includes about ten annual or perennial species almost all native to Madagascar but now widespread in all tropical and subtropical areas around the world, so much so that they become infesting in many areas.
They have whole opposite leaves, five-petalled flowers similar to those of periwinkles, solitary or collected in terminal buds.
The genre Catharanthus includes eight species but the only one used for ornamental purposes is the
The species Catharanthus roseus it is perennial even if it is normally raised as an annual as it tends to take on an ungainly appearance over the years. It is a herbaceous plant with a bushy habit, which can reach a meter in height and over time develops a woody stem near the base. It is characterized by opposite, glossy leaves of a beautiful deep green color with light-colored veins.
It blooms from spring to late autumn, producing 2.5 cm diameter, five-petalled, pink flowers with a darker spot in the central part.
Of the Catharanthus roseus there are numerous varieties that differ in the different color of the flowers which can range from white to white with a dark pink central spot, to purple, to pink.
The Catharanthus they do not require special attention and are therefore relatively easy to grow. They are perennials but are normally grown as annuals due to the fact that over the years they lose their graceful shape.
They require very bright exposures, even direct sun during the winter period while during the summer it is better to avoid the sun in the hottest hours.
The minimum winter temperatures must not fall below 13-15 ° C. For this reason, if you live in areas where temperatures drop below these values in winter, it is preferable to raise the Catharanthus in pots so that in winter they can be sheltered, while if you want to keep it in the ground, then in this case, the plant will be bred. as an annual. If grown indoors, it would be good to take the plants outdoors, on the terrace, away from direct sunlight during the summer.
The Catharanthus they should be watered frequently in summer while maintaining a fairly high environmental humidity, leaving the ground to dry on the surface between one watering and another while during the winter the irrigations are significantly reduced. For this plant we can say that the rule applies: better one watering less than one more as it is relatively resistant to drought.
TYPE OF SOIL - REPOT
The Catharanthus they are not particularly demanding in terms of soils, the only important thing is that they are soft and well draining. A good soil could consist of fertile soil, land of leaves with the addition of a little sand to help drain the watering water as you will not tolerate water stagnation. The soil does not need to be very fertile as this could negatively affect flowering.
From spring and throughout the summer fertilize once a month, using a good liquid fertilizer diluted in the watering water, halving the doses compared to what is reported in the fertilizer package. During the other periodile fertilizations to the Catharanthus must be suspended.
It is advisable to use a fertilizer that in addition to having macroelements such as nitrogen (N), phosphorus (P) and potassium (K) also has microelements such as iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), boron (B), molybdenum (Mo), all important for a correct and balanced growth of the plant.
In order to have a nice bushy habit it would be advisable to prune them at the end of winter, 7-8 cm from the ground.
Remember that when cutting plants, the tool must be cleaned and disinfected, possibly with a flame to avoid infecting the tissues.
The flowering period of Catharanthus runs from spring to late autumn.
Multiplication occurs by seed or by cutting.
MULTIPLICATION FOR TALEA
10 cm long herbaceous cuttings are taken in spring or semi-woody cuttings in summer.
The cuttings must be cut immediately under a node by cutting obliquely as this allows for a greater surface for rooting and avoids the accumulation of water on this surface.<
Use a razor blade or a sharp knife to avoid fraying of the fabrics and make sure that the tool you use for cutting is clean and disinfected (preferably with a flame) to avoid infecting the fabrics.
After removing the lower leaves, the partetagliata is immersed in a rhizogenic powder to facilitate rooting. At that point they settle in a compost made up of fertile soil and sand in equal parts by making holes with a pencil, as many as there are cuttings to rearrange.
The box or pot is then covered with a transparent plastic sheet or a cap bag after placing sticks in the ground to keep the plastic away from the cuttings and tightening the bag around the pot with a rubber band to prevent moisture loss. The pot is placed in a zone where temperatures are constant around 24 ° C. Every day the plastic is removed to control the humidity of the soil and to eliminate condensation from the plastic that will surely have formed.
Once the first shoots start to appear, it means that the cutting has taken root, at which point the plastic is finally removed and the cuttings are expected to harden. Once they are large enough, they are transplanted into the final vasode and treated like adult plants.
PARASITES AND DISEASES
The leaves wither or the flowers drop prematurely
If the leaves wither and the flowers fall for no apparent reason, the cause could be a lack of water.
Remedies: increase watering.
The leaves curl
If the leaves curl the cause could be the high temperature associated with environmental dryness.
Remedies: if possible, increase the ambient humidity but in any case bear in mind that this is a transient symptom that will pass as soon as the temperature returns to lower values.
Presence of small whitish insects on the plant
If you notice small, light-colored mobile insects on the plant you are almost certainly in the presence of aphids or as they are commonly called lice.
Remedies: treat the plant with specific pesticides easily available from a good nurseryman. These are generally systemic products, i.e. they enter the lymphatic circulation of the plant and are therefore absorbed during the nutrition of the insects.
Spots on the underside of the leaves
Spots on the underside of the leaves could mean that you are in the presence of cochineal and in particular mealy cochineal. To be sure, it is advisable to use a magnifying glass and observe. Compare it with the photo on the side. They are features, you can't go wrong. Also if you try to remove them with a fingernail, they come off easily.
Remedies: remove them with a cotton swab soaked in alcohol or if the plant is large and potted, you can wash it with water and neutral soap, rubbing very gently with a sponge to remove the parasites, after which the plant is varisced very well to eliminate all the soap. For larger plants planted outdoors, you can use specific pesticides available from a good nurseryman.
They are also known by the name of periwinkle from Madagascar and, when discovered by Europeans, it was mistakenly classified as Vinca.
It is a plant that is widely used as a medicine to treat a wide range of diseases: in India it is used for insect bites; in Central and South America for those with throat and larynx problems; in Cuba, Puerto Rico and Jamaica the flower extract is used as eye drops; in Africa, the leaves are used against hemorrhage and rheumatism; in Suriname for diabetes; in Mauritius, the leaf tea is used for dyspepsia and indigestion; in Vietnam, for diabetes and malaria and this is just to give a few examples.
Today the Catharanthus roseus it is widely used in the pharmaceutical industry all over the world. In fact, it has been discovered that its leaves contain two alkaloids, vincristine and vinblastine (normally on the market), which are used, associated with the other substances present in this plant, both for diabetes and as anticancer, in leukemia, in Hodgkin's disease. , in malignant lymphomas, in cases of neuroblastoma, in rhabdomyosarcoma, in Wilms' tumor and other tumors.
If ingested it is a poisonous plant for both people and animals.