How to Care for Fittonia in Winter? Four Tips to Prevent Leaf Wilt, Temperature Control Is Key

Because Fittonia has only average cold tolerance, how to get it through the winter becomes a headache for many flower lovers. If the method is wrong, it easily causes leaves to wilt and drop, which greatly reduces the benefits and effects of Fittonia. So how do you care for Fittonia in winter? Below, the editor will tell you a few of the most practical tips.

How to Care for Fittonia in Winter

1. Light intensity

Fittonia is a plant that climbs toward direct sunlight, but in winter you can let it receive sunlight for a period of time. Doing so not only raises the ambient temperature but also keeps its leaves green. However, if it is a warm winter, you need to pay attention to temperature changes.

2. Suitable temperature

The reason Fittonia has always been deeply loved by everyone is that its leaf veins are very special, but if the winter temperature drops below 8°C, it can easily die, and below 12°C it may suffer cold damage. So in the north it must be placed in a warm indoor area, and in the south you must also insulate it well.

3. Moderate watering

Because Fittonia is fairly afraid of drought, once the soil becomes too dry and compacted, its leaves will curl and fall off. But in winter you absolutely must not let the soil be too wet either, otherwise it is not conducive to temperature control. So usually water once every 7-10 days and just keep the soil slightly moist. For the method, you can refer to the detailed introduction in how to water Fittonia.

4. Stop fertilizing

In other seasons, fertilizer is generally applied 1-2 times a month, but when it comes to fertilizing, how do you care for Fittonia in winter? The answer is to stop fertilizing. The growth rate of Fittonia determines whether we need to fertilize, but in winter its growth basically stops, so fertilizing should also stop.

Notes on Caring for Fittonia in Winter

1. Do not propagate. Although Fittonia is very easy to propagate, because winter temperatures are relatively low, no matter which method is used, rooting is fairly difficult, and the survival rate after propagation is also low. So it is best to choose spring, when the temperature is more suitable.

2. Do not repot. Generally speaking, Fittonia needs its pot and soil changed regularly, but do not repot it in winter. The reason is that after repotting, Fittonia needs a period of time to recover, and winter temperatures are very unfavorable for it to adapt to a new environment.

3. Remove fallen leaves. Some aging leaves will drop in autumn and winter. In addition, some leaves may fall into the pot early because of improper care. Be sure to clean up these fallen leaves in time and do not let them mix into the soil, otherwise they will contaminate the soil.

4. Do not prune. In winter, Fittonia enters a dormant state and basically will not sprout new buds. One of the main purposes of pruning is to promote the plant to sprout new branches. If you prune in winter, this goal obviously cannot be achieved, so winter is not suitable for pruning.

Why You Cannot Keep Indoor Plants Well

Have you ever passed by a flower shop, happily brought home a pot of delicate, beautiful plant, or placed one beside your office desk, only for it to wither little by little as if under a spell?

No matter how you care for it, you cannot reverse the outcome of its eventual death. Unconvinced, you run to the flower shop again, only to find it is futile. With a bit of frustration, you say you will never keep plants again. Yet you cannot shake your love for plants. In fact, plants have their own temperaments.

Influencing Factors

1. Environment

Indoor ventilation is generally not particularly good, especially in summer and winter. When the air conditioner or heating is on, people are even less likely to open windows for ventilation. Using an air conditioner also changes indoor humidity and temperature. Combined with factors such as indoor lighting conditions and other environmental influences, plant growth is often inhibited, making plants prone to yellowing and then slowly dying.

The temperament of plants is also shown in the fact that they likewise need companions. This is one of the reasons why plants in a greenhouse grow better than plants in an office or home. Because greenhouses contain many plants, they can create a special environment suited to plant growth, and this environment promotes plant growth.

2. Human factors

1. Constant watering

Plants are very averse to this kind of watering. Ventilation and light are already worse than outdoors, so the moisture in the soil cannot evaporate, causing waterlogged roots, root rot, yellowing, and various other problems.

2. Frequently touched

This can injure the leaves or leaf buds of greenery and spoil their appearance, affecting both normal plant growth and visual appeal.

3. Factors from the plant itself

1. Normal metabolic yellow leaves

The bottom or a few old leaves turn yellow, while new leaves and the vast majority of leaves are healthy. For example, pothos occasionally has two yellow leaves at the bottom. Just pick them off and throw them away. There is no real impact, so there is no need to worry.

2. Pests and diseases

In fact, the plant body is like our human body and is also prone to illness. We need to go to the hospital for regular physical checkups, and plants are the same.

Specific Analysis of Common Symptoms

Symptom 1: Leaves turn yellow, leaves drop, the plant is barely alive

Diagnosis

It may be caused by the following three reasons: the place where the plant is placed is too dark and lacks even minimum light; watering is too frequent, causing root rot; the planting soil has not been changed for many years and lacks necessary nutrients.

Solution

Change the placement location and put it by a window or in a sunny place so it can receive light for a period of time; stop watering until the potting soil is dry before watering again; buy a small bottle of green-leaf fertilizer from the flower market and apply it to the soil.

Symptom 2: Newly grown stems and tender leaves are very sparse

Diagnosis

Because of a severe lack of light, old leaves wither while new leaves are thin, weak, and sparse. In horticulture there is a specific term for this called "etiolation" or "leggy growth."

Solution

Choose shade-tolerant plants suitable for indoor growth, or you can choose a dedicated ultraviolet lamp to supplement light for the plants (this lamp is not recommended for beginners).

Symptom 3: Flowers fall and stems wither

Diagnosis

Lack of water. Indoor plants are unattended, and some flowering plants that need daily watering will wither. In addition, lack of light is also a problem.

Solution

There is a very simple method. When you have no spare time to manage them, place a tray filled with water under the flowerpot.

Symptom 4: The plant dries up and dies

Diagnosis

Insect infestation. Indoor greenery usually rarely gets insects. Flowering plants that do get insects, such as marguerite daisy, usually already had insects before they were placed in the office (that is, they very likely already had insects when purchased).

Solution

You need to spray insecticide and expose the plant to sunlight. This is not suitable to do in an indoor environment and must be done outdoors. But this may take time, so indoor spaces are basically not suitable for keeping flowering plants. Flowering plants are more prone to insects than leafy plants, so they are not recommended.

Symptom 5: Leaves first turn yellow, then black

Diagnosis

After the leaves turn yellow, you remove the diseased leaves once, but they still continue to turn black. The leaves were still plump and juicy two months ago, so it can be determined to be air-conditioning sickness in the plant.

Solution

Too much watering, nutrient deficiency, and bacterial diseases are possible, but the main issue is being placed under an air conditioner, which affects normal plant growth. If the plant is still relatively healthy, you can spray it with insecticidal and fungicidal medicine.

Symptom 6: White things on potted plants, tiny pests

Diagnosis

This is scale insects at work.

Solution

You can use one of chlorpyrifos, acephate, or buprofezin, dilute with water according to the instructions, and spray 2-3 times, with an interval of 10 days between each time.

Specific Solutions for Common Plant Symptoms

Dracaena fragrans

Symptoms

Leaves droop and gradually turn yellow and dry.

Solution

When watering, it is very important to check whether water leaks from the bottom of the pot and whether the soil is aerated. You can insert a thin wire down along the edge of the pot to help aerate it. Check whether the soil is dry or moist. If it is dry, it means your plant has been deprived of water for too long and needs watering, and you should water until water leaks from the bottom of the pot. If it is moist, it means you have watered too much, so move it to a ventilated place to help the water evaporate. Of course, now you also need to prevent cold damage.

Pachira aquatica

Symptoms

Leaves turn yellow and drop

Solution

Pachira aquatica likes high temperatures and places with ample sunlight. It cannot be placed in a shaded place for a long time and should be put in a place with sufficient light; Pachira aquatica is a drought-tolerant plant, so do not water too frequently, and water must not accumulate in the pot; check whether the roots have rotted. If the roots have rotted, remove the rotten roots, disinfect them with carbendazim or potassium permanganate, and replant. If your planting soil is clayey, you can mix in some river sand.

Murraya paniculata

Symptoms

Leaves dry up and drop

Solution

The light is too poor, so it needs to be moved to a place with better sunlight. Of course, using tea water to water flowers can also cause wilting and leaf drop, so you must switch to watering with clean water.

Lucky bamboo

Symptoms

It keeps dropping yellow leaves and the stems keep withering

Solution

If it is placed in a shaded environment for a long time, the leaves cannot get enough sunlight and cannot form chlorophyll, so the whole plant's leaves turn yellow and then fall off. Supplementing light can prevent this problem. Check the potting soil. If there is dry compaction, change the soil. Usually apply thin fertilizer frequently and water with some alum water at the appropriate time. Lucky bamboo is a foliage plant and should be given fertilizer mainly based on nitrogen fertilizer.

Hyacinth

Symptoms

Root rot

Solution

If it is hydroponic, the water level should just reach the root plate. After the roots grow out, the water level should be lower than the root plate; for hydroponically grown hyacinths, you must change the water regularly to keep it clean; hydroponic hyacinths do not need nutrient solution; if only the roots have rotted and the bulb is fine, clean off the rotten roots completely, then if conditions permit, disinfect with potassium permanganate and dry in a ventilated place; replant in soil. As long as the root plate is not damaged, the chance of saving it is still quite high. If the bulb is also moldy and rotten, first clean the moldy areas thoroughly, peel off the rotten parts, and also check whether there are signs of rot inside the surrounding bulb body. Finally, disinfect, dry, and replant (soil planting is recommended).

Kumquat tree

Symptoms

Dry and withered

Solution

The ambient temperature where the kumquat tree is kept must not be lower than 8°C; use loose, fertile soil with good granular structure. This kind of soil has large porosity, which helps drain excess water and contains enough air; keep the soil moist, but not too moist, and absolutely do not let water accumulate, otherwise root rot easily occurs; in summer, water in the morning or evening, and in winter water at noon when the temperature is a little warmer; it is best to water with rainwater or river water. If you use tap water, let it sit for a few days before watering.

Fittonia

Symptoms

Leaves are wilted

Solution

It may be that the roots were damaged when it was first planted, so wait a while; Fittonia needs to be exposed to some sunlight appropriately; most cases of wilted Fittonia leaves are caused by lack of water. Water it a little, water it thoroughly, and then you can put it in the sun for a while; remember that many plants cannot be placed next to heating, and Fittonia is no exception. Do not place it in a place that is too cold either. If winter is too cold, you can cover it with a plastic bag at night and remove it during the day.

Christmas cactus

Symptoms

Does not bloom

Solution

Apply less nitrogen fertilizer and fertilizers containing more nitrogen. If applied too much, vegetative growth becomes too vigorous and reproductive growth is inhibited. At this point, Christmas cactus will become reluctant to bloom. Christmas cactus can bloom smoothly only under light conditions with short days and long nights; in a low-temperature environment below 15°C, flower bud development in Christmas cactus is delayed, and this can easily cause bud death, known as blind buds. In addition, if the ambient temperature drops to around 0°C, the flower buds will freeze and die. So the temperature must be kept at 15-20°C to ensure normal flower bud development. Every spring, it is best to combine repotting with cutting off some of the older fleshy stems of the Christmas cactus, carefully knock the plant out of the pot, and use a sharp knife to trim away a layer of old roots from the surface of the root ball to stimulate new root growth. In this way, the plant's ability to absorb fertilizer increases, its growth vigor becomes stronger, and naturally it produces more flowers.

Comprehensive Care Methods

1. Water moderately

Because indoor air circulation is relatively poor, water evaporation from the potting soil is small, and green plants are often potted with appearance in mind, so ceramic pots are used more often. This kind of pot is neither breathable nor water-permeable, further reducing moisture loss from the potting soil. Therefore, try to control the amount of watering, otherwise the roots of green plants can very easily be soaked in water for a long time and rot.

2. Maintain humidity

Plants are even more sensitive to air humidity than we are. Potted plants cannot adapt to overheated, dry air, and it also tends to make some pests more rampant. To maintain humidity for potted plants, you may take the following measures:

① Use a humidifier;

② Place the plants together in one spot;

③ Place the plants on a tray filled with water and pebbles (it is best if the water does not cover the pebbles);

④ When using an air conditioner for a long time, spray the leaves appropriately to meet the greenery's water needs.

3. Give the plants a bath

Giving plants a "bath" (rinsing the plants with a hose or nozzle) can remove many pests. Giving plants a bath in late autumn can also remove dust from the leaves. Be careful not to rinse too forcefully, so as not to damage the branches and leaves. At the same time, also be careful not to let the plants get scratched during the rinsing process.

4. Consider the light needs of greenery

When caring for plants, pay attention to their placement. Light-loving plants should be placed in places with sufficient light as much as possible. If light is insufficient, you can often change their placement and let the plants enjoy sufficient photosynthesis at regular intervals.

5. Repot in time

Unless the roots of a potted plant have filled the pot with no room left to spread, repotting is not necessary. The best time to repot is in early spring. Also note that, depending on the situation, you should water thoroughly once before repotting, and repot when the potting soil is moderately moist and dry.

Identification and Prevention of Cold Injury and Freeze Injury in Flowering Trees and Shrubs

Potted or field-grown flowering trees and shrubs, when a cold wave suddenly sweeps south in late autumn and early winter, or when the "first frost" suddenly arrives, can easily suffer cold injury or freeze injury; in spring, when potted flowers are moved outdoors or when the covering film is removed from protected cultivation of flowering trees and shrubs, a sudden late-arriving "late frost" or "late spring cold snap" can also very likely cause the plants to suffer cold injury or freeze injury again. Whether it is large-scale commercial cultivation or a small number of potted plants kept by flower enthusiasts, the prevention of cold injury must be given a high degree of attention, otherwise it will bring you serious losses and long-lasting "regret."

Cold injury is a physiological disease, not an infectious disease induced by the harm of pathogenic bacteria. It generally refers to damage caused by low temperature acting directly on the plant, including cold injury and freeze injury, and does not include indirect winter drought, frost heaving, and other winter damage.

Winter drought and frost heaving are indirect damage caused by low temperature. Winter drought refers to: some evergreen flowering plants, under certain special weather conditions in winter, such as prolonged and strong wind or a sunny day that is not very cold but has abundant sunlight, have a relatively high transpiration rate; however, because the soil temperature is relatively low, the roots absorb water slowly, and the water in the plant body cannot maintain a normal balance, causing tissues such as leaves to dehydrate and dry out and suffer damage. Its essence is a kind of drought damage; for example, the leaves of Banksia rose and jasmine suddenly dry up on dry, cold, sunny days. Frost heaving refers to: when meltwater from snow seeps into the soil and freezes again, some plants, especially seedlings or herbaceous flowers, are often lifted up together with the frozen soil, thus destroying the close contact between the root system and the soil, and even tearing the root mass apart; before the root system has time to recover, weather conditions that promote strong transpiration occur again, causing the plant to wilt and die. For example, wintersweet planted in flower pots, if placed in a very shaded and cold place in winter, because the potting soil is relatively wet and freezes, the root ball is lifted up and separated from the pot wall. If this is not discovered in time and it is not replanted properly, or moved to a warmer environment, it is very likely that the root system will be exposed, lose water, and necrose, ultimately leading to the death of the plant.

I. Types and Causes of Cold Injury

Because the causes of cold injury differ somewhat, the harm they bring also differs. The differences between cold injury and general infectious diseases are: first, it is not contagious, and no pathogens appear in the damaged parts; second, the same kind of flowering tree or shrub placed in the same environment often shows disease symptoms overnight at the same time, and tender shoots and new leaves are the most severely affected; third, it occurs under low temperature or especially cold weather conditions, and the degree of harm caused is related to the species of the flowering tree or shrub, the duration of the low temperature, the speed of temperature recovery, and the lower limit of the low temperature.

1. Causes of cold injury

Some ornamental plants native to the tropics or subtropics, after being affected for several days or even just a few hours by low temperatures above freezing (0°C~5°C or a little higher), suffer severe damage to or death of their tissue structure. This kind of cold injury, which does not reach the degree of freezing inside the tissues, is called "cold injury" and is damage formed when normal intracellular metabolism is disturbed and disrupted, tending toward disorder and producing toxic substances. The different physiological activities and metabolic processes of a plant each have their own maximum, minimum, and optimum temperatures. When the environmental temperature changes, their physiological activities and metabolic processes are all affected to different degrees; if they exceed a certain range, the coordinated relationships among them are destroyed, producing large amounts of substances that would not be produced and accumulated under normal conditions. Further research found that under conditions of cold injury, the rate of protein hydrolysis increases by 4~9 times compared with normal conditions; nucleic acid metabolism is also severely disturbed; in addition, cooling also affects the oxidative activity of sensitive mitochondrial membranes in plant cells.

From this it can be seen: first, the ornamental plant species that suffer cold injury are usually plants native to the tropics or subtropics; second, the temperature condition under which cold injury occurs is damage from low temperatures above freezing; third, the time required to cause cold injury may be long or short, usually several days, or even only a few hours. Generally, in late autumn and early winter or early spring, sudden changes in temperature are most likely to cause cold injury in flowering and foliage plants native to the tropics or subtropics. The usual symptoms are that overly tender new shoots and young leaves "turn purple," "turn brown," "turn yellow," "wilt," and "necrose," such as frost-struck scarlet sage, evergreen bamboo-leaf, kalanchoe, bougainvillea, and purple bamboo-leaf, all of which belong to this category.

2. Causes of freeze injury

Freeze injury refers to damage caused by freezing inside the tissues of ornamental plants in an environment with an air temperature below 0°C, or when they encounter prolonged ultra-low temperatures.

There are two situations in which ice crystals appear inside plant tissues: one is freezing inside the cells, and the other is freezing between the cells. The former refers to when plant tissues freeze very quickly, ice crystals form in the vacuoles and protoplasm, destroying the structure of the protoplasm and causing protein denaturation. Some membranes within the protoplasm are also punctured, usually leading to the death of the tissue, so the result of this kind of "freeze injury" is extremely serious and irreversible. For example, when a cold wave suddenly sweeps south in early winter in the north, causing a large temperature drop in a short time, the winter of 2004 caused the death of a large number of foliage plants in southern China due to freeze injury; in early December 2005, in the Hefei area, the temperature suddenly dropped from 12°C~15°C to -3°C~-5°C, causing severe freezing of the leaves and young stems of a large number of field-grown Magnoliaceae flowering trees, such as Manglietia guinanensis, Michelia yunshanensis, Manglietia insignis, and Manglietia ruyuanensis. The latter refers to when, as the environmental temperature gradually drops, ice crystals gradually form inside plant tissues. Because the concentration of the solution in the intercellular spaces is generally lower than that of the protoplasm and vacuolar sap, when the cooling rate is not too fast, the water in the intercellular spaces reaches freezing point and freezes before the inside of the cells. The formation of ice crystals also causes water in the protoplast to move outward, thereby causing concentration of the cell sap, dehydration of the protoplasm, precipitation of proteins, degeneration of the cell membrane, and rupture of the cell wall; when ice crystals form in the intercellular spaces, whether the cell tissue is killed depends on the freezing resistance of the cells and the speed and number of times of freezing and thawing; one of the mechanisms of freeze injury is protoplasmic dehydration. Its consequences are the same as dehydration under drought conditions, namely that mechanical stress produced by deformation of the cell wall causes irreversible damage to the structure of the protoplasm; after the cell sap is concentrated, the concentrations of salt ions and organic acids increase, which may also poison the protoplasm. The severity of freeze injury is related to the speed of freezing: the faster the freezing, the more severe the damage, because when freezing is fast, the possibility of intracellular freezing is greater; if freezing is limited to the intercellular spaces, then the faster the freezing, the faster the cells lose water and contract, and the greater the destructive effect of the resulting mechanical stress. The serious consequences caused by freeze injury are also related to the speed of thawing of the frozen tissue. Generally, under conditions of intracellular freezing, tissue necrosis inevitably results, regardless of the thawing speed; however, under conditions of intercellular freezing, the faster the thawing, the greater the damage, because the cell wall rapidly absorbs the water produced by melting ice and expands, but the protoplasm attached to the cell wall absorbs water slowly, so it is torn and damaged. For example, after red bellflower and bougainvillea are severely frozen, because the temperature rises rapidly, the bark is torn and the plants die.

II. Specific Manifestations of Cold Injury in Ornamental Plants

1. Blackening of the xylem

Among the various tissues of mature branches of woody flowering plants, the cambium is the most cold-resistant, followed by the phloem, while the xylem and pith are the least cold-resistant. Therefore, mild freeze injury shows only discoloration of the pith, moderate freeze injury shows discoloration of the xylem, and only severe freeze injury freezes and damages the phloem. If the cambium in the stem or branch becomes discolored, it loses its ability to recover, which may lead to the death of the whole plant.

2. Cracking and necrosis of the bark

Some flowering trees and shrubs native to tropical and southern subtropical regions whose bark contains a relatively high water content, such as Chinese hibiscus, red bellflower, Fagraea ceilanica, cinnamon, money tree, crown-of-thorns, and Ficus 'Golden Coin.' When the environmental temperature drops to about -3°C, not only the leaves and branches freeze to death, but even the outer bark of the stem, especially the root crown area, cracks and necroses because the water in the tissues forms ice crystals and expands with cold and contracts with heat, even causing the death of the whole plant.

Cold injury in white magnolia

Cold injury in purple bamboo grass


Cold injury in anthurium

Cold injury in giant taro

Cold injury in kalanchoe

Cold injury in Philodendron 'Golden Emperor'

Freeze injury in candelabra cactus

3. Changes in the color of tender shoots and new leaves
The first is "yellowing." In cold seasons, because the temperature is too low, the leaves of some flowers that require relatively high overwintering temperatures also turn yellow due to cold injury, or even fall off, such as anthurium, spider plant types, trailing pothos, and Peperomia 'Watermelon'; the second is "whitening." For example, spider plant, amaryllis, and Tradescantia zebrina placed or planted outdoors, when encountering relatively low temperatures, the tender shoots and new leaves lose their original luster and show the abnormal change of "whitening and loss of green"; the third is "scorching." The tender shoots and new leaves of some ornamental plants, due to damage such as frost, show "scorching" on the new leaves, such as spider plant, clivia, and Japanese aralia; the fourth is "purpling." Some ornamental plants, when encountering low temperatures, show "purpling and browning" at the leaf tips or leaf margins, such as money tree, Cymbidium sinense, and camellia (new leaves).
4. New shoots and tender leaves look as if scalded by boiling water
Some ornamental plants whose leaves, new shoots, or stems have a relatively high water content, including some succulents, such as pothos, Fagraea ceilanica, Chinese hibiscus, Rieger begonia, Aptenia cordifolia, clivia, giant taro, aloe, kalanchoe, broadleaf lady palm, Canary Island date palm (seedlings), Washington fan palm, money tree, and Spathiphyllum 'Green Giant,' when the environmental temperature suddenly drops from 5°C~8°C to below -3°C~-5°C and lasts for a relatively long time, their newly produced tender branches and leaves look as if they have been scalded by boiling water or cooked, all dying in a short time, and the bark cracks and peels off.
5. Browning, drying, and necrosis of new shoots and tender leaves
Some underdeveloped new shoots and tender leaves of ornamental plants, such as Ficus 'Golden Coin,' Mahonia, Japanese aralia, oleander, money tree, and Cycas, look as if they have been burned by fire, very unsightly.
6. Necrosis and hollowing of the plant body
Generally, succulents, after encountering freeze injury, often become shriveled and hollow, with the whole plant necrosing. Such as golden ball cactus, cactus, Euphorbia, and three-angled cactus.

III. Prevention and Treatment of Cold Injury in Ornamental Plants

1. Prevention of cold injury in ornamental plants
(1) Choose relatively cold-resistant flower species
Flower enthusiasts should choose foliage, flowering, or fruiting trees and shrubs according to the lowest temperature in normal years in your area or the highest room temperature that can be maintained indoors in winter (generally 5°C~6°C); in ordinary homes in the Yangtze River basin, under conditions without heating equipment, camellia, sasanqua, jasmine, white magnolia, clivia, Belgian azalea, plum blossom, wintersweet, finger citron, bitter orange, anthurium, and sago palm can be chosen, while croton, Calathea, Fittonia, desert rose, Oxalis, Polyscias, Phalaenopsis, Dieffenbachia 'Marianne,' Syngonium, and money tree cannot be chosen.
(2) Carry out cold-resistance training in stages
For generally potted Japanese white pine, black pine, Japanese red pine, Huangshan pine, Chinese quince, Chinese elm, trident maple, plum blossom, camellia, ginkgo, dragon juniper, Chinese arborvitae, and Chinese juniper, overwintering in the ground may be considered. It is best to wait until their growth for the year has ended, then carry out freeze-resistance training in several stages. The first stage is 0°C~6°C, requiring several days to several weeks, with sufficient light; evergreen types can convert starch in the leaves into sugar and divide large vacuoles into several small vacuoles, and some fatty tree species can convert starch into fat; the second stage is -3°C~-5°C, in which the fine structures and enzymes in the protoplasm reorganize so that the cells can endure dehydration caused by freezing; the third stage is between -10°C~-15°C, enabling the protoplasm to acquire relatively strong freezing resistance, thereby passing through the cold winter. Some non-cold-resistant succulent plants, such as rat-tail cactus, Haworthia, jade plant, and jade plant, if kept on a balcony or outdoors for a long time, have a process of gradual adaptation and can be raised from resisting a low temperature of 0°C to a low temperature level of -5°C~-7°C.



Freeze injury in amaryllis

Freeze injury in camellia

Freeze injury in Areca palm

Freeze injury in royal palm

Freeze injury in aloe

Freeze injury in Schefflera

Freeze injury in Philodendron bipinnatifidum

Freeze injury in bougainvillea

Freeze injury in clivia

Freeze injury in kumquat

Freeze injury in Phalaenopsis

Freeze injury in pygmy date palm

Freeze injury in banana

Freeze injury in osmanthus

Freeze injury in broadleaf lady palm

Freeze injury in monstera

Freeze injury in Cycas

Freeze injury in Japanese aralia


Freeze injury in red bellflower

Freeze injury in oleander

Freeze injury in fishtail palm

Freeze injury in round-leaf fan palm

Freeze injury in money tree

Dry freezing of sago palm

(3) Strengthen cold-resistance cultivation management

After mid-autumn, control the water and fertilizer supply for potted ornamental plants, appropriately increase the application of phosphorus and potassium fertilizers, promote lignification of branches and full tissue development, and enhance their cold resistance; for example, a 0.3% potassium dihydrogen phosphate solution can be applied or sprayed. Pruning in winter or manually removing some leaves (such as white magnolia) reduces the transpiration area and can produce good results in preventing low-temperature damage. Strengthen pest and disease control, promote robust plant growth, and prevent the appearance of autumn shoots or tender shoots.

(4) Protect the tree body from freezing

For tall field-grown camellia, osmanthus, Michelia, southern magnolia, Canary Island date palm, and sago palm, the trunk can be bound with straw rope or film, the trunk can be whitewashed, or the crown can be sprayed white (7%~10% lime milk); the crown can be covered and bound with plastic film, or wax preparations or liquid plastic can be sprayed, all of which can produce a certain anti-freezing effect.

(5) Artificially increase temperature to drive away cold

For potted plants placed in a greenhouse, on especially cold days, an electric heater or coal stove can be used inside the greenhouse to raise the temperature, especially at 5~6 a.m., the coldest time of the day, when heating must be focused; outside the greenhouse, straw curtains or felt blankets can be added for insulation. In ordinary homes, a double layer of plastic bags can be placed over the plants; for potted flowers placed indoors, if conditions permit, the air conditioner can be turned on from about 6 a.m. to 10 p.m. to avoid cold injury to anthurium, Calathea, clivia, Phalaenopsis, Oncidium, Cymbidium sinense, and Cymbidium hybridum. For field-grown flowering trees such as camellia, osmanthus, and Michelia, water can be sprayed on the crown at dawn when frost is about to occur, or frost-prevention smoke agents can be lit before frost falls in the morning, which can effectively prevent “radiation frost.”

(6) Delay budbreak to prevent late frost

Using growth regulators or other methods to prolong plant dormancy and delay budbreak can avoid frost caused by early spring cold wave attacks. For example, before budding or in late autumn, spraying field-grown plants with B9, ethephon, maleic hydrazide, potassium naphthaleneacetate (250mg/kg~500mg/kg), or maleic hydrazide (0.1%~0.2%) solution all have relatively good effects. If potted flowers encounter a "late frost" after being moved outdoors, they can be covered with double layers of large plastic film, and the covering can be removed after the temperature rises during the day.

2. Treatment of cold injury in ornamental plants

(1) Reasonable pruning

For plants that have suffered cold injury, reasonable pruning measures should be taken, and heavy pruning should not be carried out, otherwise harmful side effects will occur. So how should the pruning amount be controlled properly? It is necessary both to cut the damaged organs back to healthy parts, promoting branch renewal and growth, and to ensure a relative balance between aboveground and underground organs. Generally, pruning immediately after injury can retain 1cm~2cm of the damaged branches, to prevent the healthy branch parts from shrinking downward further; if pruning after spring begins, it can be cut back to healthy parts to facilitate wound healing; practice has proved that reasonably pruned injured plants recover faster than heavily pruned and unpruned plants.

For general evergreen potted woody flowering plants and foliage plants, all dead parts should be cut off in time, and they should be moved to a relatively warm environment.

(2) Protect and repair wounds

For large plants with freeze injury only at the local base of the trunk (northwest direction), the necrotic parts can be scraped out, wound healing agent applied, and then wrapped and protected with film, creating a relatively warm small environment for them; for some injured bonsai plants, bridge grafting or approach grafting to replace roots can be used for remedy.

(3) Strengthen pest and disease control

After ornamental plants suffer low-temperature damage, because their tree vigor is relatively weak, they are extremely susceptible to pest and disease invasion. Chemical agents can be applied in combination with the prevention and treatment of freeze injury. Among them, fungicide plus moisture-retaining adhesive has a relatively good effect, followed by fungicide plus high-lipid film; both are better than simple fungicide or whitewash. Because the main agent, the fungicide, can only play a role in surface disinfection and sterilization, while the auxiliary agents, the moisture-retaining adhesive and high-lipid film, both play a moisture-retaining role and a temperature-increasing role, all of which are conducive to the formation of callus tissue in freeze-cracked bark, thereby promoting the healing of freeze injury.

(4) Fertilize cautiously

For plants that have suffered freeze injury, high-concentration chemical fertilizer should not be applied immediately after overwintering. Instead, wait until the temperature rises and the root system recovers its absorption function, then spray or apply low-concentration liquid fertilizer; for example, 0.3% potassium dihydrogen phosphate and 0.3% urea solution can be sprayed or applied alternately, and the effect is very good.