Cordyline - Laxmanniaceae - How to care for and grow Cordyline plants
HOW TO GROW AND CARE FOR OUR PLANTS
Species: see the paragraph on "Main species"
The genre Cordyline, belongs to the family of Laxmanniaceaeand includes plants native to Australia and Asia and some species also from South America and New Zealand.
They are plants that, in their places of origin, can become real trees, often confused with the genusDracaena. Aesthetically, they are very popular plants especially for their elegance. They are plants that can be found in a wide variety of leaf shapes, sizes and colors.
They can be bred both indoors and outdoors, in temperate climate regions.
There are fifteen species of Cordyline among which we remember:
There Undivided Cordyline it is native to New Zealand and is a plant that reaches considerable dimensions in its places of origin, up to 7 m but in pots it does not exceed 120 cm.
As the name implies, it has a single (undivided) stem, not branched but at the top a tuft of linear, pointed gray-green leaves with a single rib.
If grown outdoors in temperate climate zones, it produces, during the summer, a beautiful hanging panicle inflorescence formed by numerous white flowers, tinged with red, which in autumn turn into delicious red berries.
There Cordyline terminalis (or C. fruticosa) is native to Asia and is characterized by very large leaves, with petioles, of an intense green color and variously streaked according to the variety of yellow or red.
It is a very present plant in our apartments and remains small, not exceeding 80 cm in height. It is characterized by a fairly short stem that bears lanceolate leaves, inserted close to each other, of a bronze-green color streaked with cream, pink or red.
Also in this species we find numerous cultivars among which we remember: the'Amabilis' with very deep green leaves dotted with white and pink and wide; 'Bartetii' with red / black leaves;'Guilfoylei' with leaves variously streaked with red, pink and white; 'Liberation' with leaves first red-violet and then bronze; 'King Albert' with pink leaves intensified with yellow; 'Tricolor' with large leaves streaked with pink, red and creamy white.
There Cordyline australis originally from Australia, it is a plant that in our apartments takes on the appearance of a small tree, no higher than 1m while in its places of origin it becomes a real tree even 8m high. It is characterized by an erect stem, branched in the upper part, with narrow, lanceolate or ribbon-shaped leaves of gray-green color that come together in tufts at the ends of the branches.
This species, when raised outdoors and has reached about 10 years of age, produces splendid inflorescences in the shape of feathery panicles, up to 1m long and 60 cm wide with cream-colored and fragrant flowers that will produce white berries.
There are numerous cultivars among which we remember: 'Atropurpurea' with leaves that are purplish in the basal part; 'Aureo striata' with green leaves streaked with yellow; 'Dallerianav' with leaves streaked with yellow; 'Doucetiana' with leaves characterized by white edges; 'Lineata' with very large leaves of purple color at the base; 'Purple'which, as the name implies, has leaves streaked at the purple base; 'Veitchii' with not too intense purple leaves.
There Cordyline it does not like the cold in fact it lives well at temperatures around 18-20 ° C with a high humidity (80-85%) and abundant lighting. During the winter, temperatures must not drop below 16 ° C.
It does not like direct sun but needs a lot of light.
Where temperatures allow, the cordiline can be grown outdoors, however, away from drafts.
To clean the leaves, use a damp cloth. NEVER use foliar polishes.
They are slow growing plants.
There Cordyline it requires a fairly humid soil but without stagnation of water. During the spring-summer period, it should be watered when you notice that the soil begins to dry out, not before; vice versa, during the autumn-winter period, it is watered just enough so that the soil does not dry out.
Since the Cordyline they are plants that need very humid environments (80-85%) it is advisable to spray the leaves every day during the summer.
The Cordyline they are plants very sensitive to fluorine even at very low concentrations so it is better to use rainwater or demineralized water and be careful about the type of fertilizer that is administered.
TYPE OF SOIL - REPOT
ThereCordyline it is generally repotted when one realizes that the roots are too constrained in the pot that hosts it. So to check, in the spring the plant is extracted from the pot and the roots are checked.
A soil formed by moorland and broad-leaved leaves in equal parts is used, to which a small amount of slow-release fertilizer is added.
It is good practice to place pieces of earthenware on the bottom of the pot, in order to facilitate the drainage of irrigation water.
I always recommend using terracotta pots, a porous material, as they favor the soil to breathe.
Throughout the spring and summer period, the cordyline should be fertilized every 2/3 weeks with a liquid fertilizer mixed with the irrigation water. During the autumn-winter period they must suspend the fertilizations.
As for the type of fertilizer to be administered, there are many types on the market but it is a good idea to read the label that specifies the composition. It is preferable to use complete fertilizers, i.e. fertilizers that in addition to having the so-called macroelements such as nitrogen (N), phosphorus (P), potassium (K) also contain the so-called microelements, i.e. those compounds that the plant needs in minimal (but still needs it) such as magnesium (Mg), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), ilboro (B), molybdenum (Mo), all important for a correct and balanced growth of the plant.
Reduce the doses compared to what is indicated on the package.
The Cordyline it is not common for them to bloom indoors but if grown outdoors and the temperature conditions allow it, they give breathtaking blooms.
ThereCordyline it cannot be pruned. Only the leaves that dry up are eliminated to prevent them from becoming a vehicle for parasitic diseases.
I always recommend sterilizing the tool that is used for cutting (preferably with a flame) to avoid infecting the tissues.
Lacordiline can be multiplied by seeds (even if it is very infrequent) or better by apical cuttings of the stem.
From the mother plant, at the beginning of spring, apical cuttings are taken from portions of the stem at least 7-8 cm long.
It is the base with rhizogenic hormones in powder (available from a good nurseryman) to facilitate rooting and the cutting is planted in a soil based on peat and sand seeds in equal parts.
The vase with the cutting must be small, no more than 7 cm and the vase and cutting must be closed with transparent plastic. Use sticks that you will place in the soil to keep the plastic away from the cutting.
The pot should be placed in a place where there is abundant light but no direct sun and a temperature around 21 ° C. Every day open the casing and check the humidity of the soil and make sure that it is always moist and eliminate the condensation that has formed in the plastic.
When the new leaves start to appear, it means the cordilyne cutting has taken root. Then remove the plastic and grow it as an adult plant.
PARASITES AND DISEASES
The leaves are withered, drooping and fall
This symptom is almost always associated with different factors, all linked to a bad cultivation technique: temperatures that are too high, an environment that is too dry.
Remedies: it is necessary to make an analysis on how the plant is raised according to the indications given in the sheet and to proceed accordingly.
Brown spots on the underside of the leaves
Brown spots on the leaves could indicate the presence of the cochineal and in particular the brown cochineal. To be sure, use a magnifying glass and compare them with the photo on the side; you can't go wrong, they are characteristics; also if you try to remove them with a fingernail, they come off immediately.
Remedies: use 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 eliminate parasites. Once this is done, rinse the plant very well to remove all the soap. For larger plants planted outdoors, use specific pesticides available from a good nurseryman.
The leaves have necrotic spots both at the edges and in the center of the leaf, grayish-white in the center and surrounded by a brown-yellow halo
If you notice this symptom your cordyline is definitely undergoing a fungal attack, and in particular an attack of Colletotrichum spp., a disease better known as anthracnose.
Remedies: it is necessary to chemically intervene with specific products.In any case, prevention is the best cure which consists in checking that the environment is not too humid.
(Photo of an attack of anthracnose on butcher's broom similar to what it looks like on Cordyline).
Sheets with oily-looking stains
If the leaves, starting from those placed further down, appear as small oily-looking spots, delimited by the rib that gradually enlarge becoming oval, irregular and surrounded by a yellow halo, you are certainly in the presence of an attack fungal caused byPhytophtora spp.
Remedies: first of all they are preventive. Since the excessive humidity associated with high temperatures are the ideal climate for these pathogens, regulate accordingly.Once the attack is underway it is necessary to make treatments based on Phenylamides that you will find in specialized stores.
The nameCordyline comes from the Greek kordyle «club »due to the fact that the roots of some species take the shape of a club.
We want to present these two images taken from the Habitas website (of the National Museums Northern Ireland) which shows images of the Cordyline australis used as road trees.