How to propagate peony seedlings? Latest technical method tutorial
The peony is a valuable woody flowering plant unique to China. It is a perennial deciduous small shrub of the genus Paeonia in the family Paeoniaceae, and has long been known as the “king of flowers.” In May 1985 it was rated second among China's top ten famous flowers. Its propagation methods include division, grafting, and sowing, but division and grafting are the most common, while sowing is mostly used to breed new varieties. Let's take a look below at peony seedling propagation techniques!
Division propagation
Dig up an entire large, vigorously growing peony plant, then separate it at the points where the root system's textures meet. How many divisions each plant is split into depends on the size of the original plant; large ones can be divided into more, small ones into fewer. Generally, every 3 to 4 branches form one division, and each should have a relatively complete root system. Then mix a little sulfur powder with mud and apply it evenly to the wounds on the roots, and it can be planted separately. The time for division propagation is during the period from the Autumn Equinox to Frost's Descent each year, and it is best done at the proper time. At this time, the air and soil temperatures are relatively high, and the peony is in a semi-dormant state, but there is still a fairly long period of vegetative growth, so division and planting has a less serious effect on root growth, and after division and planting some new roots and a small number of shoot buds can still grow. If division and planting are done too late, root growth that year is very weak, or no new roots form, and the following spring the plant develops even more weakly; weak roots cannot tolerate drought and the plant easily dies. If division is done too early, when air and soil temperatures are relatively high, it can still grow rapidly, and this easily causes autumn growth.
Cuttage propagation
Cuttage propagation is a method that uses the peony's branches, which readily produce adventitious roots, to propagate new plants, and is one of the asexual propagation methods. The method is to first cut off the branch to be used for cutting, detach it from the mother plant, then insert it into soil or another medium to make it root and become a new plant. For peony cuttage propagation, choose soil shoots of the current year that have emerged from the peony's roots, or, when pruning and shaping the peony, choose branches that are firm in stem, plump in terminal bud, and free of pests and diseases as cuttings, 10 to 18 cm long. The peony's roots are fleshy roots, and it likes a dry environment, dislikes moisture, and tolerates drought. Therefore, the nursery bed should be chosen in a ventilated, sunny place, and built up into a raised bed for raising seedlings. When cutting, after finishing one bed, irrigate that bed, watering thoroughly in one go.
Seed propagation
Seed propagation is the use of seeds to reproduce offspring or to breed new varieties, and is a sexual propagation method. Before sowing, the soil must be fairly carefully prepared and disinfected; the land should be deeply plowed and finely worked, and sufficient base fertilizer applied. Then build small beds 70 to 80 cm wide; either hole sowing or row sowing can be used. Do not sow too deeply; 3 to 4 cm is the limit. After sowing, cover with soil level with the bed surface. Then gently firm the soil, and immediately water thoroughly.
Layering propagation
Peony layering propagation is a propagation method that makes use of the principle that branches can produce adventitious roots. The branch is bent down or buried with soil on the plant, without being detached from the mother plant, and the soil is kept moist; the buried part of the branch takes root, and it is then cut off and planted to become a new plant. It likewise belongs to the asexual propagation methods of the peony. This method mainly includes: the pot-nesting and soil-mounding layering method and the double-flat method.
Tissue culture
Tissue culture propagation is based on the totipotency of plant tissue cells, using the peony's embryos, flower buds, stem tips, young leaves, and petioles for in vitro culture. Generally, these materials are placed in 75% alcohol and soaked for 5 to 10 minutes, then immediately put into sterile water for washing, then soaked in a 5% antiseptic solution for 7 to 10 minutes for surface sterilization, then rinsed 3 to 4 times with sterile water, and finally placed on the culture medium for aseptic culture. The basic culture medium is MS, and the other additional components mainly include different concentrations or different combinations of indoleacetic acid, naphthaleneacetic acid, indolebutyric acid, gibberellin, hydrolyzed protein, and so on.
Grafting propagation
1. Inlay grafting: Use peony root as the rootstock. Because peony root is soft and has no hard core, it is easy to graft; the root is thick and short, with abundant nutrients, and after the graft takes, early growth is vigorous. If peony root is used for grafting, the xylem is harder and grafting is relatively difficult, but the lifespan is longer. The best time for grafting is generally late September to early October each year, and the rootstock used is a robust, pest- and disease-free peony root 2 to 3 cm in diameter and 10 to 15 cm long.
2. Side grafting: Side grafting is a method of top grafting to change the head and improve varieties, using the many branches on inferior peony varieties or 8- to 10-year-old medicinal peony plants to graft excellent varieties of different colors. The grafting time is early July to mid-August. First select a peony plant of excellent variety, vigorous growth, and free of pests and diseases, and cut soil shoots that have emerged from the ground, or short branches of the current year 5 to 7 cm long; it is best to use short branches with 2 to 3 strong buds as the scion. Leave one petiole on the scion. After choosing the scion, make an oblique cut on the back of the lower bud of the scion into a horse-ear shape, then make another oblique cut on the other side of the horse-ear shape into a wedge shape, so that after grafting both sides can contact the cambium tissue between the xylem and phloem, which makes it easier to survive. Before and after side grafting of the peony, except during the rainy season when no irrigation is applied, the suitable moisture for normal plant growth should be maintained.
3. Bud grafting: Bud grafting is carried out from May to July, and it is best to graft on a sunny day. The methods include the bark-patch method and the bud-replacement method. The bark-patch method is to cut away a rectangular or shield-shaped notch together with the xylem on the current year's branch of the rootstock, then cut off the axillary bud of the scion together with the xylem into a bud piece of the same size and shape as that on the rootstock, then quickly press the bud piece onto the notch on the rootstock and tie it tightly with plastic string. The bud-replacement method is to remove the axillary bud together with the cambium at the grafting site on the rootstock, keeping the intact bud embryo on the xylem, then in the same way peel off the axillary bud of the scion, quickly slip it onto the bud embryo of the rootstock, taking care that the two fit together, and finally tie it tightly with plastic string. After grafting, the plant should be watered, the soil loosened, and fertilizer applied in good time to promote healing.