What are the propagation methods for peonies? Beginners can understand at a glance
The herbaceous peony counts as a rather precious flower, somewhat similar to the tree peony but also different. The tree peony is called the king of flowers, while the herbaceous peony is called the prime minister of flowers, and the herbaceous peony is also more commonly grown than the tree peony. The herbaceous peony is a perennial herbaceous plant with fleshy roots, native to northern China. Wild species are currently distributed in areas such as the Qinling Mountains and the Dabie Mountains. There are now more than a thousand varieties worldwide, and about 180 in China. So, how is the herbaceous peony propagated?
The traditional propagation methods for the herbaceous peony include sowing, water culture, division, cuttings, layering, tissue culture and so on, among which division is the most commonly used method.
1. Sowing method
Sow in autumn, and roots can form in the same year. Before sowing, first pick the mature seeds and sow them promptly. After sowing, cover the seeds with a layer of fine sandy soil and keep them moist at all times. Seedling growth is very slow; even plants that root in the same year need 3-4 years to bloom.
The fruit of the herbaceous peony is a follicle, and each follicle contains 1 to 7 seeds. When the seeds mature, the follicle splits open and releases the seeds. They can be harvested when the follicles turn yellow; too early and the seeds are not ripe, too late and the seed coat turns black and hard, making emergence difficult.
For propagation by sowing, it is best to sow the seeds immediately after they mature; the later the sowing, the lower the germination rate. Herbaceous peony seeds exhibit epicotyl dormancy. After sowing, they root in the autumn of the same year, and the buds only emerge after the warmth of the following spring. Seedlings grow slowly; some buds may take 3 to 4 years to bloom, and others only bloom in the 5th to 6th year.
2. Water culture method
When the room temperature is between 18°C and 28°C, the water culture method can be used. Water culture can be maintained for 4-7 days; when the buds are about to open, they can be taken out and cut for placing in a vase.
3. Division method
The best time for division is from late September to early October. Dig up the root clump, shake off the attached soil, and cut it apart with a knife so that each root cluster has 2 to 3 buds, preferably 3 to 5 buds, then plant the divided root clusters in a prepared nursery bed. If the divided root cluster is relatively large (with 3 to 5 buds), it may bloom the next year, but the flowers will be small, so it is better to remove them to allow the plant to grow well. If the root cluster is small (2 to 3 buds), growth the next year will be poor or it will not bloom, and it generally needs 2 to 5 years of cultivation.
The best time for division is from late September to early October, and it should absolutely not be done in spring. The optimal time for division varies with local climate conditions. The basis for determining the division time is: when the leaves of the herbaceous peony just begin to turn black in late autumn, the entire clump can be dug up and divided.
First dig out the roots of the mother plant, let them dry for one day, then cut and divide the roots according to the natural form of the herbaceous peony roots, with each root cluster bearing 4-5 buds. Apply a little sulfur powder to the cut surfaces of the roots to prevent pathogen invasion, then let them dry for another 1-2 days before planting them separately.
After division and planting, there is still a fairly long period before the soil freezes. During this time, the newly planted herbaceous peony can grow new roots, which can absorb sufficient water and nutrients and accumulate them in the plant body, which is beneficial to the growth of the whole plant the following year. Another propagation method is sowing: when the herbaceous peony seeds mature in August, the fruit splits open, and they should be sown immediately after collection, or stored in moist sand. The sowing site should preferably be a sandy soil rich in humus, sheltered from the wind and facing the sun, with good soil and drainage.
4. Cutting method
Choose a nursery site with higher terrain and good drainage for the cutting bed. After loosening the bed soil, spread a 15 cm thick layer of river sand, and disinfect the river sand with 0.5% potassium permanganate. Vermiculite or perlite can also be used as the cutting medium. Build a shade frame 1.5 m high over the bed. According to experience in places such as Changchun, taking cuttings in mid-July gives the best results. The cuttings are 10 to 15 cm long, with two nodes; leave one compound leaf with a few leaflets, and cut off the lower compound leaf together with its petiole. After quickly dipping in a solution of 500×10 to 1000×10 naphthalene acetic acid or indole acetic acid, insert the cuttings at a depth of about 5 cm, with spacing such that the leaves do not overlap each other.
After insertion, water thoroughly, then cover with a plastic tunnel. According to observation, rooting is best when the medium temperature is 28 to 30°C and the humidity is 50%. Keep the temperature inside the cutting tunnel at 20 to 25°C and the humidity at 80% to 90%; then roots can form 20 to 30 days after insertion, and dormant buds are formed. After rooting, reduce the amount of misting and watering, and gradually remove the plastic tunnel and shade frame. Cutting seedlings grow slowly and need to be covered with soil in the bed to overwinter, then moved to open-field planting the following spring.
The cutting method can use root cuttings or stem cuttings. The root cutting method uses the broken roots from autumn division of the herbaceous peony, cut into 5 to 10 cm root segments and inserted into a deeply dug and leveled trench 10 to 15 cm deep, then covered with 5 to 10 cm of fine soil and watered thoroughly. During autumn division, the broken roots can be collected, cut into 5 to 10 cm sections, and buried and inserted in soil 10 to 15 cm deep. In the stem cutting method, about two weeks before flowering, take the middle part of the stem consisting of two nodes as the cutting, insert it about one and a half inches deep into sandy soil in a hotbed, provide shade and water frequently, and after one and a half to two months it can root and form dormant buds.
5. Layering method
In spring, take the young shoots that have just emerged and grown, pass them through the drainage hole of a flower pot and lead them into a pot with a diameter of 15 to 20 cm. Gradually fill with soil as they grow, keep the pot soil moist, and by summer they can root. Before winter, cut off the stem below the pot, and a potted herbaceous peony is formed.
6. Modern tissue culture method
Plant tissue culture, that is, plant aseptic culture technology, is based on the theory that plant cells are totipotent. It uses excised organs, tissues or cells of the herbaceous peony (such as roots, stems, leaves, etc.) under aseptic conditions and suitable artificial medium, light, temperature and other conditions to induce callus, adventitious buds and adventitious roots, and finally form a complete plant with the same heredity as the mother plant. This technology is also called cloning technology, achieves the purpose of rapid propagation, and has wide application value.