Detailed Explanation of Flower Dwarfing Cultivation Methods
How to carry out flower dwarfing cultivation.
Key points for flower dwarfing cultivation:
I. Asexual propagation
Using asexual propagation methods such as grafting, cuttings and layering can all achieve a dwarfing effect, shortening the flowering stage, reducing plant height and making the plant shape compact. Grafting can achieve dwarfing by selecting dwarf varieties. For cuttings, plant height can be determined by considering the timing of cutting; for example, chrysanthemums cut in late July can be dwarfed and lodging controlled. In addition, the bud-bearing cutting method can allow large-flowered dahlias, which normally grow tall, to be planted in pots a little over ten cm in diameter, with a plant height of only about a foot yet with large, brightly coloured flowers.
II. Shaping and pruning
Through shaping, the main branches are removed while the plant is young to encourage side branches to sprout, and then excess or poorly grown side branches are pruned away, so as to achieve a full plant shape, a low plant and improved ornamental value. Roses, Salvia splendens, azaleas, foliage plants and others are mostly dwarfed by this pruning method. Narcissus can be dwarfed by piercing or carving to destroy the growing point.
III. Controlling fertilisation
Apply phosphorus and potassium fertiliser to potted flowers at the right time and apply less nitrogen fertiliser to control vegetative growth and achieve dwarfing.
IV. Artificial bending of trunks
Artificially twisting the branches and trunks obstructs the plant's nutrient transport channels, slows the plant's growth rate and achieves a low flower plant shape. It is generally used more often in the making of small bonsai.
V. Using plant growth regulators
1. Spraying Salvia splendens plants with paclobutrazol can shorten their internodes, reduce leaf area and deepen leaf colour, thereby changing the phenomena of tall stems, sparse flowers and leaves, and severe flower drop in Salvia splendens, and improving ornamental value. In addition, it is also often used for dwarfing flowers such as snapdragons and chrysanthemums.
2. Treating plants such as Salvia splendens with mepiquat chloride can reduce plant height by 26%, and also shorten stem nodes and increase the number of branches, improving ornamental value.
3. Treating plants with B9 can inhibit the vegetative growth of morning glory, dwarfing it by 61.5-67% during the vegetative growth period and by 40.5% at full bloom, thereby making the plant shape short, the branches and leaves compact and the flowering concentrated.
4. Using chlormequat to inhibit the vegetative growth of petunias and others can dwarf their plant shape and improve ornamental value.
VI. Radiation treatment
Some flowers can also have their growth conditions changed by radiation treatment, thereby achieving dwarfing. For example: treating narcissus bulbs with gamma rays can control narcissus growth and dwarf the narcissus plant. Treating canna with 60°C can reduce canna height by 30-50 cm, improving ornamental value.
1. Select dwarf-type varieties. The characteristics of dwarf varieties are many buds and strong branching ability, low branching position, wide branching angle, short internodes and a compact plant shape. The main root is not obvious, the lateral roots are well developed and there are many fibrous roots.
2. Grow short, sturdy seedlings. Use nutrient pot seedling raising to limit the deep development of the main root, promote well-developed fibrous roots and correspondingly inhibit the growth of stems and leaves above ground.
3. Prepare a good growing medium. The growing medium is the foundation for good growth of potted flowers, and it is required to be rich in organic matter, with a good granular structure, fertile and loose, and with comprehensive nutrition. It is made by mixing and composting leaf mould, garden soil, pond mud, peat soil, river sand, organic fertiliser, phosphate fertiliser, bone meal, plant ash and so on. The pH value is slightly acidic to slightly alkaline, and the specific adjustment should be made according to the adaptability of different flower varieties to acidity and alkalinity.
4. Cut the radicle before potting. When flower seedlings are planted in pots, shorten the radicle (main root), spread the lateral roots out in all directions when transplanting, and fill in soil in layers.
5. Repotting, fertiliser control and water withholding. For potted flowers, nutrient soil base fertiliser is the main thing; therefore, through repotting, the growing medium must be constantly renewed, generally repotting once every 1 to 2 years, moving from a small pot to a large pot and replacing old soil with new soil according to the plant's growth. In conjunction with repotting, carry out root trimming and branch training, improve the tree structure and promote a short, sturdy form. Control nitrogen fertiliser, increase the application of phosphorus and potassium fertiliser, and by all means avoid excessive watering, to prevent leggy growth and root rot causing seedling death. Especially during the peak growth period, water must be restricted and fertiliser controlled, so that the potting soil is dry and wet alternately, saving water and reducing fertiliser, promoting steady growth and achieving many branches, many flowers, dense nodes, short branches and a dwarfed plant.
6. Strengthen pruning and shaping. Pinch out the growing tips of flowers and trees in good time once they reach a certain height, adopt opening the branching angle and twisting and bending branches for shaping, inhibit apical dominance, shorten the vegetative growth cycle and promote flowering and fruiting.
7. Chemical regulation. Apply chemically synthesised growth inhibitors to promote dwarfing. When flower seedlings are transplanted into pots, mix a certain amount of paclobutrazol into the growing medium, and during the growth period spray or drench with 0.15% to 0.25% paclobutrazol, or use growth inhibitors such as chlormequat and B9, which can inhibit cell elongation, promote cell division and thickening growth, and achieve the goals of fat leaves and sturdy branches, a dwarfed and compact crown, and many and brightly coloured flowers, improving ornamental value.