Detailed Explanation of Key Points on Asarum Seed Propagation Techniques

Asarum, aliases: Chinese wild ginger, pot grass wild ginger, Latin name: Asarum sieboldii Miq. Aristolochiaceae, Asarum genus perennial herb; rhizome erect or creeping, diameter 2-3 mm, internode length 1-2 cm, with multiple fibrous roots. Leaves usually 2, leaf blade heart-shaped or ovate-heart-shaped, apex acuminate or acute, base deeply heart-shaped, apex rounded, leaf surface sparsely covered with short hairs, denser on veins, leaf back hairy only on veins; stamens inserted at middle of ovary, filaments nearly equal to or slightly longer than anthers, connective prominent, short conical; ovary semi-inferior or nearly superior, spherical, relatively short, stigma lateral. Fruit nearly spherical, diameter about 1.5 cm, brownish-yellow. Flowering period April-May.

Growth Habits

Asarum prefers cool, moist environments, and avoids strong light and drought. Soil should be loose, fertile, and rich in organic matter.

Generally sown in early July, seeds crack in early August, radicles emerge in mid-August, can reach 4 cm by early September, and over 6 cm by October. No seedlings emerge the same year; after breaking dormancy through low temperatures below 4°C, by the following spring when soil temperature rises to about 6°C, young buds emerge from the soil. At 8-12°C, peak emergence occurs. Asarum grows extremely slowly; in the second year after sowing, only two cotyledons grow; in the third spring, one true leaf grows; in the fourth year, still five true leaves, or a few with 2 true leaves, and still very few flower; in the fifth and sixth years, most have 2 true leaves and flower and set seed abundantly. In spring, seedlings emerge, aboveground parts basically take shape by May, and no new branches or leaves grow afterward; even if stems and leaves are lost due to pests, diseases, or injury, no regrowth occurs that year. Rhizomes dormant underground, form a small bud in autumn, and after overwintering, smaller leaves emerge the following year. Therefore, protecting healthy aboveground growth is extremely important.

Seeds have dormancy habits, so after harvesting, seeds need to be stored with moisture to allow embryo continuation, differentiation, and development; after 30-55 days, after-ripening is completed. Seeds avoid drying, have short lifespan, generally about 30 days.

Sexual propagation can be done by drilling or broadcasting, with broadcasting being better. Freshly harvested seeds have a germination rate of 96%, dry-stored for 20 days is 81%, 40 days is 29%, 60 days is only 2%. Therefore, after seeds mature and are harvested in June-July, they should be sown immediately. If sowing cannot be done for some reason, mix 3 parts wet sand with 1 part seeds evenly, bury in a shaded area to maintain appropriate moisture, but sowing must not be later than the end of July; too late affects root growth. About 5 kg of fresh seeds are needed per mu.

Broadcasting: Forest intercropping seedling cultivation mostly uses broadcasting. Because the soil is loose and fertile, seeds emerge easily, and seedlings are evenly distributed, benefiting root growth. Before sowing, remove 3-5 cm from the bed surface, level the seedbed bottom with an iron rake, mix seeds with 5-10 times fine sand or fine humus soil, evenly scatter on the trough surface, seed spacing 1-2 cm, then cover with sieved fine humus soil 1-1.5 cm. Cover the bed surface with a layer of brushwood or leaves to preserve moisture and prevent rain erosion. Sowing rate is 15 g per sq m.

Drilling: Open horizontal rows on the bed surface with row spacing 10 cm, width 5-6 cm, depth about 3 cm flat-bottomed shallow furrows, evenly scatter seeds into furrows (seed spacing 1-2 cm, sowing rate 12-15 g per sq m;), cover with sieved fine humus soil 1-1.5 cm, tread once, water, after 2-3 days cover with a layer of brushwood or leaves to preserve moisture.

After sowing, Asarum roots that same year but does not emerge; in the second spring, before emergence, promptly remove the cover to facilitate emergence.

Transplanting: Seedlings are transplanted after 2-3 years of cultivation. Planting can be done in spring or autumn, but autumn planting is better. Autumn planting is done after leaves wither, spring planting before buds sprout; select strong seedlings with complete roots and no pests or diseases. On a pre-prepared seedbed, open horizontal furrows with row spacing 15-20 cm, depth 9-10 cm for clump planting. Clump spacing 8-10 cm, plant 3-4 small seedlings per clump, 2-3 large seedlings, buds separated, slightly raised, fibrous roots spread in a fan shape; if soil is dry, water, after water seeps in, cover with soil 7-8 cm (field transplanting can cover shallower), press slightly. After autumn planting, cover the bed surface with dead branches and fallen leaves to prevent rain erosion or soil compaction; if transplanting in early spring, build a shade shed. Rhizome propagation is mostly done in combination with harvesting for medicine. After digging out Asarum, most rhizomes and fibrous roots are processed for medicine; select rhizomes with plump, robust terminal buds, cut into seed pieces 4-5 cm long, with 2-3 buds and 15-20 fibrous roots.

1 Seed Screening

Asarum seeds mature in mid-to-late June. After picking, pile for 2-3 days, wait until fruits crack and flesh becomes powdery, rub on a sieve, wash the seeds and flesh that fall below the sieve, scoop out and discard the shriveled seeds floating on the water surface, scoop out the semi-mature seeds suspended in the water for separate sowing, and use the full seeds that sink to the bottom for seedling cultivation.

2 Seed Disinfection

Asarum seeds often carry various pathogens. To avoid or reduce seeds carrying various pathogenic bacteria, seeds need to be disinfected before sowing. Soak seeds in 50% carbendazim wettable powder 1000x solution or 50% procymidone wettable powder 1000x solution for 30 minutes, remove and air-dry slightly before sowing.

3 Timely Sowing

Asarum seeds have physiological after-ripening characteristics and cannot be stored dry at room temperature. Therefore, after seeds mature and are harvested and cleaned in mid-to-late June, they should be sown immediately; for seeds that cannot be sown in time for some reason, sand storage treatment is needed. Sand-stored seeds can be sown at any time, but no later than early August. Sowing too late easily breaks radicles; seeds with broken radicles will not emerge after sowing.

4 Covering Soil Thickness

Asarum seeds are tiny, with weak germ emergence ability; too thick soil cover during sowing affects emergence, reduces emergence rate, and prolongs emergence period; too thin cover, surface soil drying easily causes bud damage. So, during sowing, appropriately control soil cover thickness, generally 1 cm is suitable.