A detailed guide to rose propagation techniques: master the method and grow healthy seedlings

The rose is a plant of the genus Rosa in the family Rosaceae. Its propagation is divided into 2 types: asexual propagation and sexual propagation. Sexual propagation is mostly used to breed new varieties or produce rootstock. Asexual propagation includes methods such as cuttings, division, layering and tissue culture. Cutting propagation not only preserves the superior characteristics of the mother plant, but is also simple and easy to learn, fast to propagate and has a high survival rate. Let us now take a look at the rose cutting propagation technique!

Growth habits

Although the rose is not strict about climate and soil requirements, it is more suitable to use loose, fertile loam rich in organic matter, slightly acidic and with good drainage. It likes a warm environment with ample sunlight and good air circulation. For most varieties, the optimum temperature is 15-26°C during the day and 10-15°C at night. When the winter temperature falls below 5°C, it enters dormancy. Some varieties can tolerate a low temperature of -15°C and a high temperature of 35°C. When the summer temperature stays above 30°C continuously, it enters semi-dormancy, the plant grows poorly, and although it can still form flower buds, the flowers are small with few petals, dull in color and lacking luster, losing their ornamental value.

Cutting time

Rose cuttings can be taken in both spring and autumn. In spring, this is from late April to the end of May. At this time the climate is mild and the branches are vigorous, and roots can form 1 month after insertion, with a high survival rate. Autumn cuttings are taken from late August to the end of October. At this time, cuttings are greatly affected by the temperature difference between day and night, rooting is relatively slower, requiring 40-50 days to root, and the survival rate is slightly lower than that of spring cuttings.

Seedbed preparation

For rose cutting seedbeds, it is best to choose a place with deep soil, loose structure, good permeability, good drainage and air circulation. The seedbed is 1 m wide and 3 m long. The seedbed size has little effect on the survival of the cuttings and should be determined according to need. When large-scale propagation is required, a slightly larger one may be chosen; otherwise, reduce it.

Substrate selection

Rose cuttings can also root when inserted directly into ordinary soil, but the survival rate is not high and it is not suitable for large-scale production. Therefore, fine sand is generally chosen as the substrate. It is best to use unused fine sand. To prevent the cuttings from rotting during the rooting process, formaldehyde can be added to the fine sand at 5 ml/cubic meter, and the fine sand should be spread out in the sun on clean ground and turned about 3 times to let the formaldehyde completely volatilize. After 3-5 days, the bed can be filled. When filling with fine sand, it should be spread evenly on the seedbed, pressed lightly, and watered once thoroughly. While the water is still not dry, use a wooden block to gently scrape the sand surface level.

Collecting branches

Select vigorous, pest- and disease-free (powdery mildew and black spot) upper one-year-old healthy branches from the plant. Branches that are too old or too tender are both unsuitable and affect the survival rate. Branches whose flowers have just faded are the best. After cutting the branches, to prevent powdery mildew and sooty mold during the cutting process, spray with a 1000-fold dilution of 75% chlorothalonil wettable powder.

Cutting treatment

When too many branches have been collected, they should be soaked in water or stacked under a shade shed (water should be sprayed frequently to maintain moisture). First cut off the faded flowers on the upper part of the branches, select the middle and lower parts of the branches, and cut them into sections of about 10 cm each as 1 cutting, retaining 3-4 axillary buds on each. Do not keep leaves, or keep only 1-2 leaves at the top, to prevent loss of water and nutrients from the cuttings, so as to facilitate rooting and control the growth of branches and leaves. 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 cut should be smooth so as to form callus tissue and facilitate rooting. It must not be split, otherwise it will be difficult to root and form young plants. The collected branches should be cut as soon as possible, generally completed within 1-2 hours.

Cutting method

For rose cutting propagation, try to achieve cutting, treating and inserting in sequence. When inserting, do not damage the bark. Generally, first use a small wooden stick 0.6-0.8 cm 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 10×15 cm. After insertion, press the sand lightly with your hand. When inserting, be careful to maintain the polarity of the cutting, especially for those without leaves; they must not be inserted upside down (keep the bud eyes facing upward), otherwise the survival rate will be affected. For those with leaves, it is best to make the leaves face one direction (the bright direction). After all are inserted, scatter a small amount of fine sand and water once thoroughly so that the cuttings and the sand are closely combined.

Management after insertion

1. Build a shed for shade: The optimum temperature for rose rooting is 20°C to 25°C. During the cutting period, a shed needs to be built for shade. A plastic shed can regulate the temperature and humidity of the soil and air. A shade net can prevent direct sunlight and lower the temperature. If the temperature is too high, in addition to covering with a shade net, watering to cool down and ventilation to cool down can also be used.

2. Water at the right time: In the early stage of rose cuttings, the cuttings have not yet sprouted leaves, so water supply should not be too much. Generally, watering once every 7 to 10 days is enough. After one month, the cuttings begin to root and sprout, and water consumption gradually increases, so water once every 3 to 5 days. The amount of watering should be determined according to soil moisture and air humidity, so that the soil remains moderately dry and wet.

3. Reasonable fertilization: Rose cuttings do not need much fertilizer. Since base fertilizer was already applied when preparing the land, there is no need to fertilize the soil again before the seedlings are transplanted, but foliar fertilization should be carried out. That is, one month after cutting, apply foliar fertilization once every half month, alternating 0.3% urea liquid fertilizer and 0.2% monopotassium phosphate liquid fertilizer, to promote rooting.