Repair succulents in the winter
Succulents and cactaceae are grown most of the time far from their range of origin and therefore with climatic conditions that are not exactly the ideal ones for their growth.
To solve these climatic and environmental differences, solutions can be found such as greenhouse cultivation or indoor cultivation of plants.
When we grow plants such as cacti and succulent plants, however, we must always try to guarantee the normal seasonal cycle regarding the hours of light and temperatures to ensure that our plant always remains healthy and always has a good flowering. Consequently, our succulents must go into vegetative rest during the winter and do not have to stay all year round with summer temperatures of 20-25 ° C. However, if we left them outside without any type of shelter, our plants would not resist the excessive winter feddo, typical of many areas of our country but very far from the winter climate present in the areas of origin of the succulent plants. To avoid excessive cold and at the same time ensure that succulents and cactaceae undergo winter vegetative stasis we can shelter them with greenhouses and tunnels, ideal for keeping temperatures a little milder than outside.
Plants to protect from the cold in winter (part I)
Will it be warm or cold? Winter, of course! Not possessing the crystal ball, it is impossible to hazard a prediction on this increasingly crazy weather, which from the Immaculate Conception onwards oscillates between meters of snow and sunny skies with a mild air ...
But one thing we can say for sure: no matter how the season goes, non-rustic plants cannot overcome it without our anti-cold help. Help that must be differentiated according to the type of plant and, of course, the climatic zone of residence, but also in relation to the daily weather forecast. The matter is not simple, but it is worth a piece of advice on all: one more protection is better than one less protection, because it makes the difference between saving the plant or losing it.
Delicate plants to protect
A species is defined as "delicate" when it resists up to about 15 ° C, and goes into suffering and then dies by falling below 12 ° C, of course above zero.
They belong to this category, in addition to almost all normal houseplants, the exotic flowering plants and several succulents. To name a few: Allamanda, Aristolochia, Asarina, Banksia, Bauhinia, Calliandra, Cassia (or Senna), Cestrum, Choisya, Clusia, Cuphea, Erythrina, Eugenia, Hibiscus rosa-sinensis, Iochroma, Ipomoea, Jacobinia, Mandevillea, Pandorea, Petraea, Plumeria, Protea , Sesbania, Solandra, Stephanotis, Streptosolen, Thunbergia, Tibouchina, tropical water lilies and lotuses, but the list is completely partial.
The succulent are very cold, with the exception of most of the Cactaceae, of Sedum and gods Delosperma and all the Sempervivum.
They are all plants that go grown in pots in Northern Italy and along the Apennine mountains, to be able to move it to the warmth in winter, while in slightly milder areas it can be hospitalized only when thermal drops are expected, and in Southern Italy they can also be reared in the open ground, however following the weather forecast every day from December to February.
When buying a plant you don't know, make sure it has a name tag on it, or have it tell you and write it immediately on your mobile: you will need it not only to know how to treat the new arrival, but especially in view of the winter, to provide any protection.
Semi-acoustic plants to protect
All those plants that withstand temperatures up to 5-6 ° C, and occasional drops down to 0 ° C or even 2-3 degrees below zero are semi-acoustic., as long as for short periods, with dry substrate (water lowers the temperature, causes the roots to rot or even freezes them) and in a sunny position sheltered from cold winds.
If you are unable to ensure these favorable conditions, when the thermometer is expected to drop below 5 ° C, it is better to protect them, because the risk of damage is high. IS the damages often do not manifest themselves immediately, but after a week or even at the spring recovery, which becomes delayed and stunted, often forcing to eliminate the plant. Semi-acoustics are also compulsorily cultivated in pots from the Po Valley upwards and on the peninsular mountains, while in the coastal Mediterranean areas they can also live in the open ground, always with an eye to the weather and a hand on the protective sheets.
Between semi-acoustic exotics include: Abutilon, Anigozanthus (and in general Australian plants), exotic bamboos, Brugmansia, Callistemon, Cesalpinia, Cycas, Dipladenia, Hardenbergia, Leptospermum, Strelitzia, Zamia and local water lilies, always to mention only the most famous. Between semi-acoustic succulents there are almost all Cactaceae.
Rustic plants to protect
The category most insensitive to the cold includes species that undoubtedly resist up to –5 ° C without any damage: some tolerate up to –25/30 ° C, such as rose and apple trees, others tolerate up to –10/12/15 ° C, but only if perfectly dry, in the sun and without cold wind.
If winter is "normal", they spend it outdoors without problems in the Po Valley (where the minimum "normally" do not fall below –6/7 ° C), while on the Alps for the less "polar", a drop below zero of more than 10 degrees must make it possible to put a hand to the protective sheets or to move to shelter, if possible.
All plants belonging to the Italian flora are rustic, according to the type of plant defined by the climatic zone to which it belongs: eg. the oleander it has been a naturalized species in the South for millennia, but in the Alps it cannot overwinter outdoors, like all plants belonging to the same type, namely that of "Mediterranean plants". The exponents of this specific category, in the Alps and the Apennine ridge, they should only be grown in pots.
Protect the plants in the garden
In the open ground of the garden, delicate plants can only survive in Southern Italy, always in sunny locations and sheltered from the north and north winds, even better if it is possible to cover them with a plastic sheet if necessary in case of heavy rain combined with drops in temperature.
The speech also applies to semi-acoustics, which in a similar location can also do it in the hills of the South, while in the mountains of the South they are at risk: it is essential to provide for the preparation of protections, starting from a trellis that supports a large plastic sheet to save from rain and snow .
The rustics in general get along without serious damage, but some small protective caution can also be reserved for them.
Trees and shrubs, if planted in their climatic zone, usually do not need protection, except in the first winter after plantingwhen it is good mulch the base with dry grass or leaves, natural or gift straw, bark, peat or compost, shavings, wood chips or sawdust, pieces of jute or canvas, to be fixed with stones. The rosebushes are an exception, imperturbable even in the Alps.
The perennial herbaceous plants that in colder areas dry out or lose the aerial part, they must be mulched at the base, the precaution is even more valid for plants planted from spring onwards. In addition to basal mulching, the other important means of protection is provided by straw mats also combined with heavy plastic or bubble wrap, useful for the protection of “out of zone” shrubs, including banana trees.
Plants go first eventually pruned to reduce its size, then tied with the soft plastic thread, trying to tighten the branches and the foliage without tightening too much. Then the hair is wrapped with one or more straw mats, starting from the base of the trunk, stopping them with the spiral-wound tie: it is an easy operation to carry out if there are two of you if you are alone, stop the end of the mat at the bottom tying it to the trunk. Don't over tighten: the plant must breathe, especially at the top, where the mat must not close the gap. For safety, in addition to the mats you can also wrap a plastic sheet, always leaving the top free, which you will close with another cloth if the weather foresees heavy rain or snow, removing it after the rainfall has stopped. Instead of mats you can use the non-woven fabric by choosing the heavier one or putting it double. You can finish the closures made with the ties by securing the flourishes with clothespins.
In the case of plants of particular value, you can set up a structure of wooden posts, well fixed in the ground and slightly higher than the specimen to be protected, which enclose the plant and on which to spread the protective sheets, to be fixed well with the staple gun.
At the end of the operations, only trees, shrubs and herbaceous plants suitable for the climate of the area must remain unprotected in the garden. If it snows, immediately remove the snow (with an old broom) from the pergola and gazebo, greenhouse, protected plants and unprotected evergreen shrubs (watch out for hedges!), To prevent the flakes from freezing, weighing down the structures and plants and deforming them. or damaging them.
Protect potted plants
A plant lives in pots or because it is a species delicate or semi-rustic, which therefore must be protected, or because only a terrace or balcony is available, and in this case the rustic plants can overwinter without problems, while all the others need protection, withdrawing them indoors if possible, or providing on site if there is no space inside or if the vase is now immovable.
Before any kind of protection it is good, where possible, to prune the specimens to rearrange them and reduce their encumbrance and, for the larger ones, to proceed with the tying of the foliage as described for the shrubs in the garden.
Small vessels can be admitted to cold greenhouse: the balcony models on the market are numerous, with two, three or four floors or without shelves for tall plants, self-supporting or leaning, with metal frame and soft plastic cover sheets or plexiglass panels, for all needs and pockets. For the set-up see below.
If the pots must remain outside, the most classic protection consists of: wrapping the base of the plant with straw, dry leaves or sawdust wrapping the container with a jute, non-woven or bubble wrap cloth lifting the pot from the cold floor with wooden or polystyrene tablets, without obstructing the drainage hole plastic cloth heavy transparent or bubble wrap or non-woven fabric to be wrapped around the hair (open at the top), securing it with plastic wire and clothespins, or wrapped with straws, leaving the top open to give light.
They are also useful moving the pots against the more sheltered part of the balcony, against a wall, perhaps covered by the roof or the balcony above, better if facing south and where the gusts of cold wind do not arrive and the more delicate specimens are huddled together, so as to be able to cover them with a plastic sheet ( left slightly open) or non-woven fabric (to be closed well).
Remember that the “less robust” rustics, such as cyclamen, camellias, azaleas and rhododendrons, if the temperature drops below 0 ° C at night, they must be moved between the double glazing or on the landing, to put them back out the next day (if you return above zero). This precaution also applies in the case of rain, which spoils the corollas or buds and favors molds. Rain always lowers the temperature of the earth and therefore of the roots: only rustic plants can bear it, as long as they have no saucer.
There snow instead it does not create big problems, if it remains for a few days: as soon as the snow ends, run a finger around the stem to remove the crystals which, freezing, could damage the tissues then, when it has melted, lift the vase and sweep away the water below. But if the blanket rises over 20 cm, remove it as much as possible from the pots, from the protective sheets, from the greenhouse and from the floor, to avoid damage to plants, excessive weighting and underlying infiltrations. Finally the icy wind that sweeps the balcony on certain clear and very cold days can be kept at bay by lining the railing internally with mats or plastic sheets.
Materials to protect plants
If in doubt about plant resistance, switch to protection of the base of the plants, that is, of the root system and the collar. First of all, we must eliminate the grass that increases the dispersing surface by cooling the soil. Then the earth must be insulated with various materials: peat, straw, dry leaves, etc. Creating a mound of good thickness with insulating materials around the foot of the plants means exploiting the heat coming from the subsoil and at the same time preventing the cold from reaching dangerous depths.
Finally, for good plant care protect the aerial part, surrounding the plant with a metal mesh fixed to the ground with stakes, then filling the cylinder obtained with straw, dry leaves or peat, which insulate even from more intense winds.
THE plastic films in polyethylene or PVC are precious for their transparency: to build a small greenhouse around the specimens to be protected, stick some bamboo canes of appropriate height into the ground and cover the structure with a sheet or a plastic tube, closing the upper part with a tie and they fasten the lower one with stones. In this case, the foot of the plant must be protected up to a height of 15-20 cm with peat or straw placed inside the structure.
To allow a minimum of air circulation and avoid excessive condensation inside the protection, it is advisable to drill some small holes in the plastic film. Even better is the insulation with bubble polyethylene sheets (bubble wrap plastic for packaging).
Another very useful material is the TNT (non-woven fabric), which is made up of fibers pressed and glued together and allows the plant to breathe more, without causing excessive overheating on sunny days. In this case it is not necessary to leave openings, because the plant can breathe. The non-woven fabric can be used like PVC and can also be tightly wrapped around the foliage, to bring the branches closer to the trunk, for example with oleander. The conical shape obtained avoids, among other things, damage from snow accumulation and reduces the surface exposed to the wind.
(By Elena Tibiletti - Published on Gardening 10/2013)
Succulent succulent plants
The succulent succulents are widespread in our homes, they require a lot of light, otherwise the leaves turn yellow and the stems become soft or stretch a lot, taking on a pale color. These plants, in the summer season, they require abundant watering and regular while it is suspended when the temperature drops below 10 degrees. Repotting should be done every year, at the latest every two years, and the collar of the plant must always remain above the level of the soil. The succulent succulents they multiply, as well as by sowing, by leaf cuttings, for stem cutting or for division of shoots rooted. The crassula, the dudleya, the euphorbia, the mesembryanthemum, the purslane belong to this genus.
Succulent succulents - Some very popular varieties
Haworthia: It needs a lot of light and heat, even direct sun and a well-ventilated environment, but without cold drafts. It should only be watered when the soil is completely dry. During the other periods, water so much that the soil does not dry out completely. It is repotted in early spring using a soil for cacti.
Dudleya: It should be placed in a place where it can always receive abundant light. During flowering, a good fertilizer is administered to be diluted in the irrigation water. During the winter these must be completely suspended (provided that the plants are not in a heated environment), while during the summer season it is watered once every 15 days.
Echeveria agavoides: It prefers soft and incoherent soils, with high drainage. Very drought-resistant plant: water only sporadically, about once every 4-5 weeks with 1-2 glasses of water, leaving the soil dry for a couple of days before watering again.
Succulent succulent plants - Division and multiplication of Sansevieria
There Sansevieria, in the trifasciata variety with stiff sword-shaped leaves, it is a classic houseplant. Of easy cultivation, allows to give life to new plants with the division of the tufts.
- It is necessary to divide the plants of Sansevieria when we realize that the root system comes out of the earth. Young leaves would suffer and the plant would not develop.
- We remove all the earth bread taking care not to damage the roots. To facilitate the extraction, we give a few taps on the pot and gently "pull" away the plant.
- We carefully remove all the soil bringing the roots of the Sansevieria. We eliminate the superfluous earth by tapping the roots together and dividing the root system.
- Let's prepare the new pot that will welcome the plant by choosing a large enough one. We place one on the bottom crushed stone layer is one topsoil layer.
- We carefully place the plants trying to place the roots well on the layer of earth, which must be lightly pressed with the hands.
- We complete the work by filling the pot with the remaining soil. We press the earth with our hands, we water with water at room temperature.
Succulent and succulent plants: how to grow them
Succulents and succulents are absolutely irresistible: you know those polystyrene trays that contain about fifty mini-jars, the size of a two-euro coin, each with a specimen of graceful and captivating shapes? Or the subjects who are already big, beautiful chubby people, perhaps adorned by some flower and generous promises in the form of buds? One, or more than one, will enter your home: you already know that they take up very little space and that they will require very little care (few, but not none!).
Here because succulents are the most common in Italian homes, especially during the winter, when the need for greenery is strong, but it cannot always be satisfied by bulky and demanding indoor green plants.
Fat? No, succulent!
Actually, call them "succulents" that's not quite right: it is a definition that unites in the common concept all plants with fleshy leaves or stems (within which a reserve of water is collected, useful for surviving in the original dry environments). But, like all globalizations, the definition means nothing, neither from an aesthetic point of view nor from a cultural one.
First, because the "fat" take very different shapes and sizes: think about Lithops (the "living stones") or toEchinocactus grusoni (“Mother-in-law's pillow”), ai Epiphyllum ("Mother-in-law's tongues") or to the calancoe (Kalanchoe blossfeldiana), to the "mesembriantemi" (Lampranthus, Carpobrotus, Doroteanthus etc.) or to the stapeliads ...
Second, because only the species just mentioned they certainly do not want the same cultural care: claim to cultivate a Lithops like a calancoe it means bringing it to death in a short time, and vice versa. It is true that the attention to be paid to this kind of plants is very few, compared to almost all green plants, but the few must be well known and complied with.
Let's call them rather "succulent plants", The exact term in homage to the fleshiness of the fabrics, a unique fact that truly unites them. The question is not of goat's wool, precisely because each category requires different care.
Let's see then, with the help of the expert Antonio Borghi, owner nurseryman of the Borghi di Vignola (MO) farm specialized in succulent plants, what it takes to welcome them well in the apartment and make them survive the winter, perhaps with the gift of some unexpected flowering.
Cactaceae: impossible not to have at least one
This family includes all succulents shaped like a cactus, how Echinocactus, Ferocactus, Notocactus, Echinopsis, Cereus, Mammillaria, but also the Epiphyllum, with elongated and sinuous leaves, to name only the best known genera.
And if these genres are so well known and widespread, there is a reason: they are among the easiest to maintain throughout the year, generally repaying our not excessive attention with splendid and relatively long blooms during the summer, as confirmed by Borghi: "The Cactaceae are of Mexican or South American origin, their vegetative activity in Italy takes place throughout the spring -summer.
This means that, from the end of September until late March, their ideal state is "hibernation", i.e. a vegetative rest during which vital functions are reduced to a minimum useful for survival: they should be placed in a closed, dry and unheated environment (where, however, the temperature remains constantly above zero), without any water supply.
On the other hand, if they are kept in a room with a temperature between 12 and 20 ° C enter a phase of "semi-hibernation", That is, the plants do not stop all functions, but continue to vegetate minimally: in this case it will be necessary water them moderately every 20-30 days, also depending on the amount of light present, which naturally affects the vegetative activity (in the absence of light the irrigation interval will be longer and vice versa) ".
It goes without saying that not respecting the necessary rest, the plants will weaken and, in all likelihood, they will not be able to flower during the summer.
Euphorbiacee, relatives of the poinsettia
To this large and multifaceted family (which also includes the Christmas star, Euphorbia pulcherrima, to anticipate the period that awaits us shortly) belong euphorbia with completely different forms: herbaceous, fleshy or arboreal, with minimal or huge leaves or turned into thorns. Among the succulent species, the best known example is Euphorbia milii, also called "spina-christi", but they also fall into the category E. obese (sort of apparently non-thorny "ball"), E. trigona (a kind of cactus with longitudinal wings), E. caput-medusae (with twisted stems), E. platyclada etc.
On the surface, therefore, they do not seem so different from the Cactaceae, but this is not the case at all. Borghi further explains: "The succulent Euphorbiacee are native to Africa and, in Italy, they have a almost continuous cycle of activity, with simple slowdowns of functions in the periods less favorable to them, namely winter and summer. To get them through the cold season well, make sure that the temperature is in the room where they are positioned never drops below 10 ° C, and provide them with some sporadic watering ”.
Aloe and agaves, similar but very different
The genre Aloe belongs to the Liliacee family which, among the succulent forms, also includes Gasteria is Haworthia. The latter, with the absence of thorns and minute, regular and graceful shapes, lend themselves well to an impulse purchase and placement in very small spaces (even on a shelf, as long as it is reached by light).
Unlike instead of Aloe, whose growth is generally significant even just over a year, both in diameter and in height, soon becoming rather bulky, especially within four walls. Among these, a minority (A. vera, A. barbadensis, A. ferox, A. saponaria. ) is equipped with thorns whose tip ends in a hook, hooking to the skin, but generally without serious consequences.
With them, forget what has been said so far for the other succulent families: "Aloe are African species, coming from South Africa and the island of Madagascar", explains Borghi. "Therefore, belonging to the southern hemisphere, in Italy they are in maximum vegetative activity during autumn-winter, a period in which it would be preferable to prepare the best environmental conditions for them ". That is to say a luminous location, one temperature between 10 and 18 ° C, with moderate and regular irrigations every 10-15 days.
“But if you can't help but hospitalize them, know that excessive heat and lack of light induce abnormal growth, a phenomenon of "spinning" that leads to the production of thin, elongated and pale leaves. The problem is above all Aloe vera, A. ferox, A. arborescens, as a species with rapid growth and large and fleshy leaves. To avoid this effort, which generally weakens the plant, it is preferable to force it to rest: keep it in a low temperature room, but without exposing them to freezing temperatures (therefore not below 0 ° C) ".
Hopefully, you can also hospitalize aloes in the cellar or garage, where barely a minimum of light enters, as long as irrigations are limited to a drop of water once a month.
Don't confuse aloes with agaves, similar in appearance but characterized by fibrous leaves ending in a sharp point which, accidentally cutting into the skin, penetrates deeply causing considerable pain (keep all agaves away from children and pets!).
Also, the genre Agave belongs to the very different family of Agavaceae, which also include Nolina is Sansevieria (but also not succulent Dracaena is Yucca).
And, despite the similarity to aloes, the agaves they behave like cacti: “Do so send them into hibernation or semi-hibernation during the autumn-winter, as for the Cactaceae, and then bring them back to life in spring, according to their natural biological cycle ”specifies Borghi.
Aizoaceae (Mesembriantemacee), in flower in late winter
It is a large family that includes, simplifying, two large groups: on the one hand balcony or garden plants by the sea or rock, with a creeping or bushy habit, with fleshy and elongated leaves, and with corollas similar to daisies of all sizes (from 1 cm in diameter in Aptenia cordifolia up to 10-12 cm of the Hottentot fig, Carpobrotus acinaciforme), usually with fuchsia petals, more rarely orange or yellow. In addition to the two species mentioned, they are included Dorotheanthus, Lampranthus, Delosperma, all genres suitable for pot life, but only outdoors.
They are almost all perennial, which in the South can be planted in full ground, having only the foresight, in the event of an announcement of frost or snow, to cover them with dry leaves or with a non-woven sheet. In Northern Italy instead they have to live in jar, to be able to overwinter in a cool (10-12 ° C), bright room, being moderately wet every 20-25 days: only in this way will you keep them inducing them to bloom, which occurs between April and May. In fact, all Mesembriantemaceae are native to South Africa: their vegetative cycle is reversed compared to what happens in nature here.
And also the second grouping (including the Lithops, the Conophyton, the Lapidary etc., ie genera attributable to the so-called "indoor plants") is no exception to the rule: "Their moment of maximum activity occurs between September and May", explains Borghi.
“During this period, don't let them miss a temperature between 15 and 18 ° C, good lighting and regular watering every 15 days. From June onwards the dormancy and hibernation phase begins, which must be respected: place them outdoors, in the shade and do not wet them, except with a few drops after a month of drought ".
Crassule and echeverie: easy and beautiful
Numerous genera belong to the Crassulaceae, among which the best known are Crassula, Echeveria, Aeonium, Cotyledon, Pachyphytum, Kalanchoe (see below), Sedum is Sempervivum (see below).
They are all very popular and loved plants, first of all why without thorns (and therefore easier to handle and care for), then because they are more similar to normal green plants (although without requiring the care that the latter often require), and also because some of them quite easily give conspicuous and durable blooms (as is the case with calancoe, sedum and sempervivum). Finally, some tend to assume sculptural forms, however elegant and never disordered, spontaneously, without the need for pruning or constrictions.
The simplest to care for are absolutely sedum and sempervivum, at least if they originate from Europe. Conversely, all other genres come from South Africa: once again, their cycle is reversed with respect to our habits when it comes to plants. "During spring and summer crassule and echeverie go into dormancy: choose for them a location in the shade without almost watering them. When autumn arrives, place them in a protected, bright place, at a temperature of 10-18 ° C, resuming watering them moderately every 10-15 days "specifies Borghi.
Ideal would be one room without heating, a veranda, a landing, between the double glazing, where the light arrives but the temperature does not drop and does not rise excessively. Rather than forcing them to overwinter in the apartment, as for aloes, it is better to take them to the garage, cellar, tool shed, almost in the dark and at a temperature between 2-3 and 8-10 ° C, without irrigation, to bring them back outdoors. to light in advance, as soon as the night temperature remains above 12-13 ° C, sheltered from wind and rain.
The goal, of course, is there flowering: un unico ma durevole momento che, per le piante protette nel luogo giusto, si verifica tra metà gennaio e metà marzo, mentre per quelle poste al buio verrà posticipato di un mesetto dopo la ricollocazione in piena luce. Lavorate a favore dei boccioli fornendo concime a partire da una quindicina di giorni prima del periodo previsto.
Quali possono vivere in casa?
Come si diceva all’inizio, l’acquisto di una pianta succulenta prelude nella maggioranza dei casi al suo posizionamento fra quattro mura, complici la bellezza e le dimensioni ridotte.
Ma, come ha ampiamente sottolineato Borghi, a dispetto delle più diffuse convinzioni, le succulente non sono adatte a vivere recluse in appartamento: in estate prediligono l’aria aperta, all’ombra se a riposo, a mezz’ombra o mezzo sole (mai in pieno sole: si scottano!) se in attiva vegetazione. In inverno desiderano il riposo a bassa, ma non gelida, temperatura se hanno lavorato in estate, e la pensione né al caldo né al freddo se riprendono a vegetare proprio ora. Tutt’al più queste ultime tollerano un letargo forzato a bassa temperatura, procrastinando necessariamente il momento in cui vegeteranno e fioriranno. In nessun caso è consigliata la vita in casa: se è troppo caldo anche per quelle che stanno vegetando, figuratevi che inferno (letteralmente, di calore) per quelle che devono finalmente riposarsi.
Ma allora, quali succulente possiamo tenere in appartamento senza che soffrano per l’aria calda, la mancanza di luce, l’ambiente chiuso o la corrente d’aria improvvisa? “Vale la pena di provare le Haworthia, Liliacee che in natura crescono sotto i cespugli in piena ombra. In alternativa, provate le Cactacee a forma globosa e a sviluppo lento, come gli Echinocactus e i Ferocactus”.
Qual è il rischio nel mantenere in appartamento le succulente durante l’autunno-inverno? Quello di ritrovarsi piante deboli, che non fioriranno mai, soggette a marciumi basali per eccesso d’irrigazione e a parassiti come la cocciniglia cotonosa. Via libera invece nelle altre stagioni, quando il riscaldamento è spento e solo se le tapparelle rimangono alzate tutto il giorno, naturalmente.
I più facili: sedum e sempervivum
Non vi chiedono nulla, ma possono darvi tanto: Sedum is Sempervivum sono succulente che “vivono di niente” (alcune specie vengono – da sempre e tuttora – utilizzate come copertura di tetti e giardini pensili), ma con l’arrivo della bella stagione si possono riempire di fiori, più o meno appariscenti, bianchi, rosa o gialli.
Tutti i Sempervivum e quasi tutti i Sedum svernano senza problemi all’aperto, anche sotto lo zero o coperti da una coltre di neve: sono tutti quelli originari delle nostre Alpi o di altre montagne del mondo. Qualche nome? Sedum acre (fiori gialli), S. album (fiori bianchi), S. telephium (fiori rosa), S. sieboldii (fiori rosa), S. spectabile (fiori rosa), S. spathulifolium (fiori gialli) ecc. Sempervivum arachnoideum (fiori rosa-rosso), S. allionii (fiori gialli), S. tectorum (fiori rosso porpora), S. soboliferum (fiori gialli). Molti di essi sono decorativi anche per il fogliame, che varia dal verde intenso al glauco, al blu, al rosso, al porpora ecc.
Tutti questi, in inverno, non hanno bisogno di alcuna protezione, né di irrigazioni. Anzi, è proprio l’esposizione al freddo a indurne la fioritura primaverile-estiva: se rimangono a temperature superiori a 6-8 °C, non fioriranno. Il loro limite è piuttosto il caldo: in estate andrebbero tenuti a mezz’ombra, lontano da raggi solari diretti, in una posizione fresca e ventilata, possibilmente senza superare i 25 °C. Fra i Sedum, attenzione solo a S. morganianum: sotto i 5 °C gela irreparabilmente.
Utilizzateli per creare composizioni rustiche, in coccio o terracotta (anche all’interno di tegole e coppi), a piacere mescolando le diverse specie.
Calancoe, la più amata dagli italiani
Le calancoe sono fra le più amate dagli italiani: è merito del costo assai contenuto (a partire da 3-4 Euro) e della bellezza durante la fioritura – multicolore e ormai anche multiforme – che, in aggiunta, si protrae per almeno un paio di mesi.
Dalla primavera alle soglie dell’autunno vanno mantenute preferibilmente in esterni, a mezz’ombra, senza esagerare con le irrigazioni: sono in fase di riposo.
“Da ottobre e per tutto l’inverno invece sono in piena attività” osserva Borghi. “Vanno perciò collocate in un ambiente a temperatura compresa fra 12 e 18 °C, molto luminoso, dove inizieranno a fiorire”. Vengono indotte alla formazione di boccioli proprio dall’accorciarsi delle giornate, che le risveglia a partire da settembre.
“Se costrette in interni riscaldati dove la luce difetta, tenderanno a filare, cioè ad allungare notevolmente gli internodi, perdendo la caratteristica forma aggraziata, e ad assumere un colorito verde pallido tendente al bianco. Piuttosto, ponetele a 5-8 °C: ritarderanno la fioritura, ma soffriranno meno!”.
La dipladenia cresce sana e forte se viene coltivata sia in terreno aperto che in vasi ampi, tuttavia in entrambi i casi è importante fare in modo che sia esposta alla luce e al sole per molte ore al giorno. Quando arriva la stagione invernale è bene tenere sotto controllo la pianta ed essere pronti a proteggerla nel caso in cui le temperature fossero troppo basse: al di sotto dei 5-10°, infatti, può soffrire parecchio, pertanto è importante adottare delle soluzioni per ripararla dal vento e dal gelo. Se la dipladenia è situata in un terreno ampio si può proteggere posizionando dei paraventi intorno alla pianta, da mantenere soprattutto durante la sera e la notte. Di giorno, invece, se la giornata è soleggiata è meglio tenere la pianta libera e ben esposta alla luce.
I principali accorgimenti per preservare le vostre piante fino alla primavera
- Portarealchiusothepiante in vaso per alcune specie è la prima e più semplice soluzione al freddo. Vanno bene locali non riscaldati come verande e garage: l’importante è che ci sia luce a sufficienza e che il passaggio da esterno a interno sia graduale. Se le piante vivranno in appartamento, collocatele lontano da fonti di calore e vicino alle finestre orientate a seconda delle loro esigenze di sole a est e ovest per ottenere il massimo della luce, mentre a nord e a sud per necessità minori. Evitare ovunque di mettere piante in vaso vicino alle aperture, nella corrente. Controllate che abbiano sempre il giusto tasso di umidità, con nebulizzazioni sulle foglie e terriccio dei vasi mantenuto umido (ma non fradicio): ovviamente questi non sono che dei consigli generici, perché ogni pianta può richiedere condizioni ambientali assai differenti.
- Preparare una location riparata e soleggiata: se non potete ricoverare le vostre piante in un ambiente chiuso, sotto un patio o una tettoia, cercate almeno di collocarle accanto a frangivento, siepi o a ridosso di muri o pareti che possano fornire loro un minimo di riparo dai venti gelati dell’inverno. Raggruppare tanti vasi vicini uno all’altro può giovare e contribuire a trattenere il calore vicino alle piante.
- Costruire una miniserra per le piante in vaso all’aperto o un tunnel per quelle a terra richiede invece un po’ più di tempo e perizia: su internet potete trovare molti tutorial per il fai da te con legno, pvc o altri materiali di recupero e senza spendere un capitale. Che si tratti di serra a casetta o ridossata a un muro, oppure di un tunnel, abbiate cura di assicurare sempre una buona circolazione dell’aria all’interno ed evitatene il surriscaldamento durante le giornate invernali di sole, spalancando le aperture con regolarità.
- Potreste anche avere bisogno di improvvisare un piccolo impianto di riscaldamento in queste serre fredde: come fonti di calore “volanti” in questo caso molti siti suggeriscono di utilizzare luci di Natale o una lampadina da 100 watt, ovviamente di quelle predisposte per l’illuminazione esterna. Assicuratevi sempre che non siano a contatto ravvicinato coi materiali di copertura o con le parti delle piante.
- Coprire il vaso e la parte aerea delle piante (anche a terra) per difenderle dal gelo della notte è decisamente più facile: il vaso può essere avvolto in un sacco di Juta, pluriball o fogli di giornale con un’imbottitura di paglia per preservare le radici, mentre la pianta va incappucciata con materiale traspirante come il tessuto non tessuto, oppure con un telo di plastica, avendo cura in quest’ultimo caso di lasciarvelo solo lo stretto necessario, nelle ore più fredde, e poi levarlo per far circolare l’aria del mattino. Il tutto va sempre fermato con solidi legacci. Il cappuccio va rimboccato sotto il vaso e non attorno al tronco della pianta, in modo che quest’ultima possa godere del calore irradiato dalla terra inoltre andrebbe sostenuto da una piccola intelaiatura, in modo che non vada a contatto diretto con foglie e rami.
- Applicareinfineuno strato dimulch per proteggere radici e colletto della pianta dagli sbalzi termici e preservare il calore della terra: ricoprite il terreno di qualche centimetro isolante di paglia, terriccio di foglie o torba, fino alla stagione temperata.