How to Propagate Boxwood? Detailed Explanation of Seed Sowing and Cutting Methods

Boxwood (Buxus) is an evergreen shrub or small tree, an excellent street tree that can also be cultivated at home as a bonsai. Some enthusiasts, after growing their boxwood to a certain point, want to propagate it themselves but don't know exactly how to do it. The editor will introduce the seed sowing and cutting propagation methods for boxwood. Interested friends can learn together.

Boxwood

I. Seed Sowing Propagation

For sowing, harvest ripe fruits in July, spread them out to dry in the sun, then thresh to extract the seeds and store them in bags. Sow in winter or early spring. If sowing is done later than March, few seedlings will emerge that year, and most will not germinate and emerge until the second year. Before sowing, soak the seeds in 40°C warm water for a full day and night (allowing it to cool naturally), then dry them and sow. The seedbed soil should be fertile, loose sandy loam. Drill sow with a row spacing of 15-20 cm, a sowing width of 5 cm, and a sowing furrow depth of 2 cm. After sowing, cover with 1 cm of burnt mud soil, then cover with rice straw. After the seedlings emerge, remove the straw promptly and set up a shade frame. Strengthen management during the seedling stage: weed and loosen the soil, water frequently to keep the soil moist, and apply dilute cake fertilizer water. Remove the shade frame in September, leave the seedlings in the bed for another year before transplanting.

II. Cutting Propagation

This is best done during the plum rain season. Select semi-lignified healthy branches as cuttings, 10-12 cm long, with a heel at the base, keeping 5-6 pairs of leaves on the upper part. Insert to a depth of 1/2 to 2/3, with a plant-to-row spacing of 6×10 cm. After inserting, press the soil firm, water thoroughly, set up a shade frame, and spray water frequently to keep the soil moist; extra watering is needed especially during hot weather. Remove the shade frame in September to October, leave in the bed for another year before transplanting. Boxwood can also be propagated by thick-trunk cuttings: cut a relatively thick branch from a clustered plant, keep several whorls of branches and leaves on top, bury the entire trunk in yellow sandy soil or vermiculite with the branches and leaves exposed, water frequently to keep it moist, and roots will form after half a year.

Seed Sowing and Cutting Propagation and Cultivation Techniques for Euonymus bungeanus (Silk Cotton Tree)

Euonymus bungeanus is a species with high ornamental and landscape value as well as high medicinal value, and is the first choice for many users engaged in forestry planting. Let's discuss the cultivation techniques for Euonymus bungeanus together.

Euonymus bungeanus

Cultivation Techniques

Mainly propagated by seed sowing and cuttings.

Sowing

Collect seeds in autumn, rub off the aril, wash clean and dry in the sun, store in stratification, and sow in spring the following year.

Cuttings

Conducted in March in spring, or softwood cuttings can be used during the plum rain season. Cuttings are 12—15 cm long, inserted to a depth of 1/2, with sandy loam as the bed soil. Water frequently after inserting to keep the soil moist, and roots will form and the cutting will survive in about one month.

Select fertile, loose land for planting the seedlings, with spring transplanting being preferable. Before planting, dig planting holes according to the root system conditions, line them with loose fertile soil and decomposed barnyard manure. When planting, mound fine soil around the roots and press firm. Do not plant too deep, to avoid excessive root suckers. Provide appropriate shade in summer so the leaves do not become too thick, and beautiful red leaves are easily formed in autumn, enhancing the foliage display effect.

Euonymus bungeanus is a warm temperate tree species, native to the central and northern provinces of China, and also distributed in Zhejiang and Fujian. It likes light, tolerates slight shade, is cold-tolerant, and also relatively drought-tolerant. It is suitable for growing in fertile, moist sites, and can adapt to both neutral and slightly acidic soils. The root system is well developed, and its sprouting ability is strong.

A heliophilous tree species, tolerates slight shade, highly adaptable to climate, cold-tolerant, drought-tolerant, moisture-tolerant, barren-tolerant, and not demanding about soil. The root system is deep and well developed, able to resist wind, with strong root sucker sprouting ability, and grows relatively slowly. It has strong resistance to and absorption capacity for sulfur dioxide, hydrogen fluoride, and chlorine gas, and also has a strong ability to absorb and retain dust.

Cuttings

I. Collection of Euonymus bungeanus Scion Wood

The collection of cuttings is generally carried out during the dormant period from after leaf fall in autumn to before sap flow in spring, in conjunction with winter pruning of the tree. Select one-year-old branches that are robust, fully lignified, and free of pests and diseases.

II. Storage of Euonymus bungeanus Cuttings

For spring hardwood cuttings, the branches need winter storage. The storage method is: cut the branches into about 15 cm lengths, choose a higher, well-drained shady spot and dig a trench 1 m wide and 60 to 80 cm deep, with the length depending on the number of cuttings. First spread a 5 cm thick layer of wet sand on the bottom of the trench, bundle the cut cuttings in groups of 50, and place them in layers in the trench. When the scion wood reaches 20 cm from the ground, fill level with wet sand, cover with soil in a roof-ridge shape, and insert a straw bundle in the middle for ventilation.

III. Treatment of Euonymus bungeanus Cuttings

To increase the survival rate of the cuttings, 6 to 8 days before cutting, soak the cuttings in running water; if using still water, the water must be changed daily. Cut when a distinct irregular nodular growth appears at the lower cut end. Alternatively, soaking in a 1% sucrose solution for 24 hours can significantly increase the survival rate of the cuttings.

IV. Euonymus bungeanus Cutting Technique

Euonymus bungeanus

Euonymus bungeanus

Before cutting, prepare the land carefully and apply sufficient base fertilizer so the soil is loose and has adequate moisture. First make holes with a tool, insert the cuttings along the holes, then seal the holes and press firm. The cutting depth is 2/3 of the cutting length, with a plant spacing of 20 cm and a row spacing of 40 cm. Water thoroughly after inserting.

V. Euonymus bungeanus Tending and Management

1. Set up a shade frame. To conserve soil moisture, reduce the number of irrigations, and prevent soil compaction, at the end of cutting, cover the seedbed with plastic film, seal the edges with soil, and shade with a sunshade net above to avoid direct sunlight. If the temperature is too high and humidity too great, open both ends of the film to allow air circulation. Roots generally form in about three weeks. After the cuttings have rooted, gradually remove the covering in batches.

2. Irrigation. After cutting, keep the seedbed moist,

timely supplying the water needed for the cuttings to root. During the seedling stage, water with a small flow of clean water, just enough to penetrate the seedbed. Never flood-irrigate, to prevent young leaves from sticking to mud and getting scorched. Generally irrigate once every 3 to 5 days, for a total of 2 to 3 irrigations.

3. Topdressing. 40 days after cutting, to promote robust seedling growth, apply quick-acting fertilizers such as decomposed human excrement and urine, urea, ammonium sulfate, and monopotassium phosphate. Master the principles of applying topdressing in stages and applying appropriately according to the seedlings' condition.

4. Loosening soil and weeding. Weeding in the nursery begins in April and ends in September, clearing weeds at any time. Loosen the soil shallowly for small seedlings and deeply for large seedlings, generally to a depth of 2 to 4 cm, later increased to 8 to 10 cm. Stop loosening soil and weeding during the seedling hardening period. [2]

Raising Seedlings

(1) Seedling raising method. Use flat-bed seedling raising. Deep-plow the soil in late autumn. When preparing the land, apply 6000 to 8000 kg of organic fertilizer per hectare. The following spring, harrow level and smooth, make beds 1 m wide, then water thoroughly once. After the water seeps in, when the soil moisture is suitable, rake level and fine. (2) Sowing time. Generally sow from mid-to-late March to early-to-mid April; earlier sowing is better. If too late, weeds grow quickly and easily “crowd out the seedlings”, making seedling-stage management difficult. (3) Sowing rate. The conventional rate is about 10 kg per 667 sq m. The sowing rate is greatly related to seed purity and germination rate. High purity and high germination rate mean a small sowing rate; conversely, a large sowing rate. (4) Sowing. Generally drill sowing is used, opening furrows with a plow 3 to 5 cm deep and 20 to 25 cm wide. Evenly scatter the seeds into the furrows, cover with soil about 1 cm thick, and press appropriately after covering. Under suitable moisture conditions, seedlings emerge in about 20 days.

Seedling Stage Management

(1) Thinning and filling in seedlings. Thinning is generally done after the cotyledons appear and when 1 to 2 pairs of true leaves have grown; if too late, it easily causes the seedlings to become spindly and weak. Generally leave seedlings in a triangular arrangement, with a plant spacing of about 15 cm. The principle of thinning is “remove the weak and keep the strong, remove the dense and keep the sparse, remove the diseased and keep the healthy”. Fill in seedlings in conjunction with thinning. Thinning can be done at one time or in several rounds. Generally thin after watering or after rain when the soil is soft, pulling out seedlings that are weak in growth or damaged by pests and diseases. Be careful not to injure neighboring seedlings during the operation, and remove weeds at the same time. Then press appropriately and irrigate so the seedling roots are in close contact with the soil.

(2) Irrigation and topdressing. Irrigate timely and appropriately according to soil moisture. From when true leaves grow on the aboveground part until the seedlings grow rapidly, control water appropriately for “hardening off”. After hardening off, irrigate 2 to 3 times. During the rainy season, the irrigation amount depends on rainfall. Reduce the number of irrigations in the later growth period to prevent the seedlings from excessive late-season growth in autumn. In early November, irrigate once with cold-protection water. In conjunction with watering, topdress 2 to 3 times. Apply nitrogen fertilizer in the early growth stage to promote seedling growth; apply phosphorus and potassium fertilizer in the later stage to increase the degree of lignification of the seedlings.

(3) Cultivation and weeding. Timely cultivation and weeding can prevent weed growth and soil compaction, and increase soil aeration. Loosen the soil in conjunction with weeding, and follow the principle of “weed early, weed small, weed completely”. After rain and watering, loosen the soil promptly to conserve moisture. Generally, the seedlings can reach over 1 m in height in the same year, and after 2 years can be used for landscaping, or as rootstock for grafting Hokkaido boxwood or Euonymus fortunei.

Three Propagation Methods for Hokkaido Boxwood

Hokkaido boxwood is a variety of large-leaf boxwood. This boxwood is native to Japan and grows relatively fast. In northern China, Hokkaido boxwood is an excellent tree species for adding greenery and color in winter. The editor will introduce three propagation methods for Hokkaido boxwood. Friends interested in Hokkaido boxwood can learn about them together.

Hokkaido Boxwood

I. Cutting Method

The materials used for cuttings can be hardwood, softwood, single buds, or leaves. The sand bed should follow the principle of retaining water and allowing air flow without waterlogging. The medium should be disinfected with potassium permanganate or carbendazim. The cuttings need to be soaked in rooting water. After inserting, press the cutting bed firm and do not water excessively.

II. Sowing Method

After the seeds are harvested, promptly remove the red aril and dry in the shade. Before sowing, the seeds need to be sand-stored; the humidity must not be too high, and the temperature must not exceed 15°C. Sow as early as possible after the soil thaws; sowing early is preferable to late. If sown late, as air and soil temperatures rise, the seeds root and sprout quickly, the seed roots grow long, and the roots are easily broken during sowing, causing damage to the seeds.

III. Grafting Method

To cultivate large-sized, large-quantity nursery stock in a short period, Euonymus bungeanus can be used as rootstock for grafting. Euonymus bungeanus has a well-developed root system, a high transplant survival rate, and fast growth, reaching 5 cm to 6 cm in diameter at breast height in 3 to 4 years. Moreover, the Hokkaido boxwood crown forms early and has strong cold resistance.