How to grow rose seedlings from cuttings? A detailed explanation of the key technical points for southern regions

When is the best time to propagate roses by cuttings in southern regions? Roses can be propagated by cuttings in both spring and autumn. In spring, it is done in April-May, when temperatures are gradually rising; generally roots form 30 days after cuttings are taken, and the survival rate of cuttings is high. In autumn, cuttings are taken in August-October, when the temperature difference between day and night is large; after cuttings are taken, rooting is relatively slow, generally requiring 40-50 days to root, and the survival rate is slightly lower than that of spring cuttings.

1 Preparing the seedbed

1.1 Location: Choose a place with deep soil, loose structure, good aeration, good drainage and air circulation.

1.2 Specifications: 1 m wide and 3 m long, determined specifically according to need.

2 Substrate selection

Although rose cuttings inserted directly into ordinary soil can also root, the survival rate is not high, so fine sand (preferably unused) is generally chosen as the substrate. At the same time, to prevent the cuttings from rotting during rooting, formaldehyde can be added to the fine sand at 5 ml/m3, and the fine sand should be spread out on clean ground to sun and turned 3 times so that the formaldehyde completely volatilizes; after 3-5 days the bed can be filled. When filling with fine sand, spread it evenly over the seedbed, then press lightly and water once thoroughly; while the water is still not dry, gently scrape the sand surface level with a wooden block.

3 Collecting branches

Select vigorous one-year-old healthy branches from the upper part of plants that are growing vigorously and free of pests and diseases; branches whose flowers have just faded are best. After cutting the branches, spray them with 75% chlorothalonil wettable powder at 1000 times dilution to prevent powdery mildew and sooty mold during the cutting process.

4 Cutting treatment

When too many branches have been collected, soak them in water or pile them under a shade shed. For the collected branches, first cut off the faded flowers on the upper part, select the middle and lower parts of the branches, and cut them into sections of about 10 cm each to serve as 1 cutting; cut the upper end of the cutting into a flat opening and the lower end into a slanted opening, with the cut about several millimeters from the axillary bud. The cuts are required to be smooth, which helps wound healing.

5 Cutting method

As far as possible, cut, treat and insert the cuttings as you go. Before inserting, first use a small wooden stick 0.6-0.8 cm thick to make a small hole in the cutting bed, then place the cutting into the hole. The insertion depth is 1/3 of the length of the cutting, and the plant and row spacing is 10 cm x 15 cm; after inserting, press lightly with your hand. After all are inserted, sprinkle a small amount of fine sand and water thoroughly.

6 Management after cutting

6.1 Temperature: After cutting, it should not be too high, because excessively high temperature will cause the axillary buds of the cuttings to sprout quickly and grow into tender shoots, which is a sign of cutting failure. Therefore, in order to promote rooting, the temperature should be lowered, preferably controlled within the range of 22-26 degrees; when the temperature is too high, it can be lowered by watering on the shed or on the ground, or by appropriate ventilation.

6.2 Watering: In the early stage after cutting, generally watering once every 7-10 days is enough. After 30 days, the cuttings will begin to root and sprout, and water consumption is then high, so watering can be increased, generally once every 3-5 days. The amount of watering should be determined according to soil moisture and air humidity, keeping the soil moderately dry and wet. The best moisture conditions after cutting are: field water-holding capacity of the seedbed kept at about 80%, and relative air humidity 80-90%. When humidity is too high, reduce it by controlling the amount of watering and strengthening ventilation; when humidity is too low, increase it by increasing the amount of watering and the number of sprays.

6.3 Weeding: Promptly pull out weeds in the cutting bed, but do not disturb the seedlings.

7 Transplanting young seedlings

Under the condition of an ambient temperature of 22-26%, the cuttings can root after 1 month. At this time, open the plastic film every morning and evening to air the young seedlings, increasing their ventilation and light time, and after about 7-10 days the young seedlings can be transplanted into a greenhouse or flower pots. Note that the day before transplanting, water thoroughly.

8 Seedling-stage management

Potted young rose seedlings should be maintained in a shade shed or other shady place for 7-10 d. During this period, they should be sprayed with water frequently to maintain moisture; for the first few days, let them receive some sunlight every morning and evening, then gradually extend the sunlight time. Because the root system of young seedlings is not very developed, do not rush to fertilize; at least after 3 weeks, apply dilute fertilizer water about every 10 d. Although young rose seedlings survive, some growers always think the seedlings grow too slowly and, according to their own wishes, force the seedlings by topdressing. This practice must not be adopted, because young rose seedlings go through a stagnant growth period of 1-2 months from collecting cuttings, inserting them, rooting and transplanting to entering the rapid growth stage. During this time, the young rose seedlings must gradually adapt to the external environment before they can grow rapidly. If growers force the seedlings by fertilizing according to their own wishes, things often turn out contrary to expectation, resulting in the death of the seedlings. After passing through the stagnant growth period, the young rose seedlings naturally enter the rapid growth stage. At this time, some plants will produce some flower buds; in order to avoid consuming nutrients, these flower buds should be cut off in time. After 1-2 [periods] of management, the young rose seedlings can leave the nursery; at this time growers can transport them to the market for sale or transplant them to the field or larger flower pots as needed.

Cutting propagation techniques for bagged groundcover plant seedlings in southern regions

News from the China Landscape Web on July 12: There are four propagation methods for bagged groundcover plant seedlings: seed propagation, grafting propagation, cutting propagation and tissue culture. In southern regions, the most widely used, lowest-cost method that seedling farmers in various places find easier to accept is cuttings.

Influencing factors

I. Internal factors

1. Tree species characteristics

Due to genetic differences, different tree species differ greatly in morphological structure, growth and development patterns, and ability to adapt to the external environment, leading to differences in cutting survival; some root easily from cuttings, while others root with difficulty.

2. Mother plant and cuttings

Age: As a plant grows, its metabolism gradually weakens, and its vitality and adaptability gradually decline. Under normal circumstances, the rooting ability of cuttings decreases as the age of the mother plant increases. Therefore, the younger the mother plant, the stronger its vitality, and the higher the survival rate of cuttings taken from its branches. Similarly, on the same plant, using one- or two-year-old branches for cuttings makes survival easier than using perennial branches.

3. Cuttings

Developmental condition: Whether branches develop well, that is, how much nutrient material they contain, has a certain influence on cutting survival. Generally, branches on the main axis of the plant develop best, and using them as cuttings gives stronger rooting than using side branches; among branches of the same age, the thicker the better; branches on the sunny side of the crown are better than those on the shady side; basal sprouting branches are better than upper branches. In production practice, taking some tree species with a portion of two-year-old branch, that is, heel cuttings, helps increase the survival rate, which is related to the greater amount of nutrients stored in two-year-old branches.

The buds and leaves on the cuttings can supply the nutrients and growth hormones necessary for rooting, so when taking cuttings, while preventing excessive water evaporation, retain as many leaves and buds as possible to favor rooting.

II. External factors

1. Temperature

The optimum rooting temperature for most seedlings is 15°C to 25°C, with 20°C being most suitable. When the substrate temperature is 3°C to 5°C higher than the air temperature, it is most favorable for cutting rooting.

2. Moisture and aeration

After cutting, the cuttings need appropriate substrate moisture and air humidity; this is the key to rooting. First, ensure relatively high air humidity, generally 80% to 90% relative air humidity; second, maintain appropriate substrate moisture, but not too much, to avoid mold and rot at the base of the cuttings caused by poor substrate aeration. Measures such as shading and irrigation can be used to increase the survival rate. In modern seedling-raising techniques, closed cutting beds and full-sun automatic intermittent misting facilities are often used, with good results.

3. Light

Sufficient light can raise soil temperature and air temperature and promote rooting. But too strong light will dry or scorch the branches. Therefore, in the early stage of cutting and rooting, appropriate shading should be provided. As the root system grows, the light time can be gradually extended. However, plants do not all have the same light requirements; their requirements for light intensity differ with variety. According to the light intensity requirements of seedlings, we can divide ornamental seedlings into three categories: sun-loving, neutral and shade-loving.

Sun-loving seedlings like strong light, cannot tolerate shade, have a relatively high light compensation point, and can grow and develop normally only under conditions of sufficient sunlight. If light is insufficient, branches become slender, leaves turn yellow and thin, flowers are small and not vivid, and flowering is poor. Common tree species include golden dewdrop, Fujian tea, purple peony, ixora, Aglaia odorata, rose and hibiscus.

Neutral seedlings relatively like light and grow best in sufficient sunlight, but also have varying degrees of shade tolerance, such as camellia, rhododendron, Schefflera octophylla, Cordyline fruticosa and Podocarpus macrophyllus.

Shade-loving seedlings have strong shade tolerance and grow well under moderately shaded conditions, such as Taxus chinensis, Fatsia japonica, ivy, Flower Butterfly and Nephrolepis cordifolia.

Therefore, they should be placed according to the different light requirements of various plants. Place sun-loving seedlings in an open, unobstructed environment; place neutral seedlings beside large trees or under sparse forest so they receive 70% to 80% sunlight; place shade-loving seedlings under multiple layers of shade netting so they receive 40% to 70% sunlight.

4. Cutting substrate

The cutting substrate only needs to meet the cuttings' requirements for soil moisture and aeration conditions. Considering cost needs, materials are often obtained locally, choosing loose, breathable sandy loam rich in humus; when the soil is too heavy and sticky, an appropriate amount of sand, coconut coir or peat can be added to adjust it. In actual production, use a hoe to slowly break up the sandy loam, and preferably spread it out to sun for two or three days for high-temperature sterilization and disinfection.

Methods to promote rooting

I. Physical treatment

1. Mechanical treatment

Commonly used methods include ringing, scoring and constriction. After the new shoots stop growing, score, ring-bark or tie the base of the branch with wire or similar materials, which can prevent nutrients from the upper part of the branch from being transported downward, causing nutrients to be stored in the branch; by the dormant period, cut the branch off for cuttings.

2. Etiolation treatment

Cover and wrap the cuttings with black cloth, paper or plastic film to cause the branches to etiolate and soften, which favors the growth of root tissue and promotes rooting of the cuttings.

3. Heating treatment

Use facilities such as electric heating wires or hot water pipes to heat the seedbed so that the substrate temperature of the seedbed reaches 20°C to 25°C, which can increase the survival rate of cuttings. For seedlings whose branches contain more resin, such as pines and spruces, soak the cuttings in warm water for 2 hours to remove the resin and promote rooting.

II. Hormone treatment

1. Types

Plant growth hormones can promote rooting of cuttings. Commonly used ones include indoleacetic acid (IAA), indolebutyric acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), ABT rooting powder, etc.

2. Treatment methods

There are many such products on the market; we only need to buy them from regular pesticide stores and strictly follow the instructions for use.

Precautions

To prevent the seeds of annual grassy weeds from sprouting, before cutting, irrigate the substrate with an aqueous butachlor solution; generally add 20 grams of butachlor liquid per 50 kilograms of water.

Considering economic benefits, after bagging they must be able to become seedlings as quickly as possible, so when taking cuttings we insert several cuttings into the same bag at the same time. First, this prevents the situation where if one or two cuttings fail to survive, the others still survive; second, if all survive, they can quickly become seedlings and leave the nursery, reducing the time accumulated in the nursery waiting for bagged seedlings to become established.

Post-cutting maintenance

I. Temperature

Cutting branches generally root best at 15°C to 25°C, so in summer appropriate misting should be used to lower the temperature. Especially at noon when the temperature is very high, mist several times, once every one or two hours, and strengthen ventilation. In winter, some seedlings cannot withstand severe cold, such as large-leaf red grass, canna and coleus, so bamboo poles or iron rods are arched into a semi-arch over the seedbed and covered with agricultural film, and only at noon when the temperature is relatively high is the film door appropriately opened for ventilation.

II. Moisture

The substrate must not be too moist; it is best if it can be squeezed in the palm of the hand without water droplets overflowing. In summer, with high temperature and high humidity, besides the necessary misting to lower temperature, when the substrate is found to be in a moist state, do not replenish water to the cutting bed. In summer, watering should be done in the morning or evening, because at these times the soil temperature and water temperature are similar, while at hot noon the soil temperature is at least 3°C higher than the water temperature, sometimes even more than 5°C, so watering at that time harms the flowers and trees. In winter, because the weather is dry and substrate moisture evaporates easily, misting is needed at noon when the temperature is relatively high to maintain moisture. It is absolutely forbidden to water flowers and trees in the morning or evening in winter, because in winter the water temperature in the morning or evening is generally lower than the soil temperature; if flowers and trees are irrigated in the morning or evening, it has a relatively strong adverse stimulating effect, and over time this will cause the death of the flowers and trees.

III. Weed control

Once the cuttings have been inserted into bags, non-selective herbicides such as Roundup or glyphosate can no longer be used to control weeds. At this time, broadleaf weeds can only be removed manually, while annual and perennial grassy weeds can be controlled with haloxyfop or Verdict when they emerge, while the target plants, which are broadleaf crops, remain safe and sound.

IV. Topdressing

This depends on the growth condition of the flowers and trees. When the plants are growing well, no topdressing is needed; generally after more than one month of cutting, a small amount of compound fertilizer can be applied, and after application it must be watered.

When to plant roses? A brief introduction to rose planting methods and cultivation techniques

Roses are one of the world's famous ornamental plants and have a long history of cultivation in China. After roses were introduced into China in the 18th-19th centuries, they were hybridized and repeatedly backcrossed with existing varieties to breed varieties such as Chinese rose, tea rose, wild rose and rugosa rose, with extremely high ornamental value. Let us take a look below at when to plant roses!

When to plant roses?

Roses can be planted throughout the year. During the growing season, keep the root system moist, and in winter protect against cold, but the suitable time is after leaf fall in autumn to before bud break in spring, among which the period after leaf fall in autumn to before the ground freezes is the best planting period. To make the plants grow quickly and expand the flower cluster, large-hole planting must be carried out: holes 1 meter long and wide and 0.6-0.8 meters deep, or planting trenches 0.6-0.8 meters deep and wide. Apply organic fertilizer and superphosphate per plant, mix evenly with soil and apply concentrated at a soil depth of 0.2-0.5 meters; after planting, firm the soil and water thoroughly in time.

Propagation methods of roses

Rose seeds can be used for raising seedlings, but in production, cuttings from current-year soft branches are mostly used for raising seedlings, as they root easily. Precious varieties are harder to root from cuttings and can be propagated by layering or grafting; asexually propagated seedlings can bloom in the same year. For seedlings used as potted flowers, choose older branches from superior varieties and use layering to raise seedlings, and also pay attention to pruning the main buds and carrying out artificial dwarfing. For seedlings used as cut flowers, choose varieties that can form mother branches for cutting flowers and have large, brightly colored flowers for raising seedlings. Roses can also be propagated by tissue culture, water culture, division and other methods.

Planting methods of roses

1. Soil: Roses are not strict about soil requirements, tolerate drought and tolerate poor soil. Cultivation is most suitable in soil that is deep, loose, fertile, moist and well drained. They can also grow normally in heavy clay soil. Whether planted in the ground or in pots, the growing medium for roses is best made of fully decomposed sandy soil.

2. Light: Roses are light-loving flowers and relatively prefer sufficient sunlight, and are also tolerant of partial shade and relatively cold-resistant, with extremely strong adaptability. Except for overwintering in severe winter cold, they are suitable for planting throughout southern regions. During the growth period, roses should be ensured sufficient sunlight so they can have luxuriant branches and leaves and bloom more.

3. Watering: Roses like moisture and fear waterlogging. From bud break to before flowering, water appropriately more, with soil moist but not waterlogged being best. After roses finish flowering, watering should be reduced. When watering, the soil should be allowed to dry and then be watered; in the rainy season, pay attention to drainage and waterlogging prevention to avoid root rot from standing water.

4. Fertilizing: Roses relatively like fertilizer and also tolerate poor soil. In March, apply 1 to 2 times a nitrogen-based liquid fertilizer to promote luxuriant branches and leaves. In April and May, apply 2 to 3 times a phosphorus- and potassium-based fertilizer to promote more flower bud formation and more flowering. After flowering, apply one rejuvenation fertilizer, and then stop fertilizing. Roses need hilling and fertilizing once each winter.

5. Pruning: Pruning and shaping is an indispensable procedure in the cultivation of most flowers, and natural roses are no exception. Especially when cultivating them as potted flowers, more attention should be paid to pruning and shaping. Generally, mature roses are pruned once each year before spring growth starts, with a moderate amount, ensuring the rose branches are moderately dense and the appearance is attractive. Each winter, old branches and densely growing branches of roses should be pruned regularly to maintain good light transmission and ventilation, which can reduce pests and diseases.