Techniques for cultivating boxwood in Hokkaido

There are many breeding methods of Populus tomentosa in Hokkaido. Here are some commonly used methods:

1. Cutting method: cutting method is divided into hardwood and tender wood cutting method. Hardwood cuttings take place between October of each year and the end of March of the following year. For units with sufficient provenances, cuttings can be cut slightly longer, units lacking in provenances, cuttings can be slightly shorter, cuttings are 8 to 15 cm long, cuttings are generally 3 to 5 cm deep, and roots can grow after 1 month. As long as the cuttings are carried out according to the following methods, the seedlings with better growth can be obtained quickly:

1) make the sand bed with good water permeability and disinfect the sand bed with potassium permanganate or carbendazim two days in advance.

2) prepare alcohol and plant rooting powder and mix the solution according to the instructions.

3) when cutting cuttings, do not choose too young shoots, those with a high degree of Lignification are easy to take root and sprout.

4) leave the trunk and side branches when pruning, and leave the root of at least one bud to facilitate the next pruning.

5) remove the lower leaves of the cuttings and leave 2 to 3 leaves in the upper part. After the cuttings are repaired, soak them in rooting water.

6) draw a trench with a small shovel on the sand bed, press 5 to 10 cm into the cuttings, cover the soil and press it tightly. The line spacing is 10 to 20 cm.

7) the process of cutting needs to maintain appropriate temperature and humidity, watering should be based on temperature and humidity, and leaves should always be kept moist. Do not overwater, prolong the rooting time, seedlings can reduce watering appropriately after rooting.

8) it will take root about 30 days after cutting, and it can also be bowled at the right time. Bowled nutritious soil can be prepared with sand, soil and peat soil, each accounting for 1/3, to facilitate ventilation, do not fill the bowl too full.

two。 Single-bud cutting method: single-bud cutting method can be used to rapidly breed seedlings of Populus tomentosa. Cuttings should be carried out between May and October, with buds 1 to 2 centimeters long, one bud and one leaf, and leaves should be preserved. The knife for sprouting must be sharp, and the sprouts should be cut in time after being cut. The cuttage can cut 500 to 1000 seedlings per square meter, take root one month after planting, sprout in 40 to 45 days, and reach 10 to 15 centimeters in height after 2 months.

3. Leaf cutting method: choose mature leaves for cuttings, the petiole of the leaves used for cutting must be complete, when taking leaves, do not use scissors, it is best to break off the petiole from the base of the buds by hand, take along with the cuttings, or put the leaves in a clear water basin. Too long storage time of leaves will lead to the decrease of cutting survival rate. The cutting depth is 2 to 3 cm. After cutting for 20 days, the callus could be produced on the petiole base, the new root could grow from the callus after 30 days, the buds formed on the root primitive after 50 to 60 days, and the buds broke the soil and grew into new plants after 70 to 80 days. The cutter of 1 square meter can cut 1000 to 1500 leaves, and the survival rate can reach more than 95%.

4. Seed sowing method: Populus tomentosa in Hokkaido has early fruit, large seed setting quantity and high seed germination rate. When the pericarp is cracked, it should be harvested in time, otherwise the mature seeds are easy to be eaten by birds. Take off the red aril in time after the seed is harvested. When removing the aril, the force should be light, too heavy, and it is easy to crush the seed. The seeds are dried and stored in wet sand. The humidity of the sand should not be too high, and the seeds with high humidity are easy to mildew. The temperature in the storage room should not exceed 15 degrees. When the room temperature exceeds 15 degrees, the seeds are easy to germinate ahead of time. After the soil is thawed, it is necessary to sow as early as possible, sowing early rather than late, late sowing, rising air temperature and soil temperature, fast rooting and sprouting, long roots, easy to break the roots and cause damage to the seeds. The variation of seedlings bred by seeds is obvious, especially the shape of leaves. Among the seedlings, 50% to 60% of the seedling leaves are the same as the female parent, 20% to 40% of the seedling leaves become pointed, and 1% to 10% of the seedling leaves become broad. No matter how the leaf shape changes, the Arbor character and fast-growing habit of the seedlings bred by seed sowing are almost the same as those of the female parent. However, it should be noted that when breeding seedlings, do not easily throw away those sharp-leaf type seedlings.

5. Grafting method: although the growth rate of Hokkaido boxwood is 3 to 5 times faster than that of ordinary Euonymus tomentosa, it is necessary to make Hokkaido boxwood grow into large seedlings with a DBH of 5 to 6 cm, at least 6 to 8 years, and more than 10 to 15 years or more. In order to cultivate large sizes and large quantities of seedlings within 5 to 6 years, silk cotton wood used as rootstock must be cultivated first. Silk cotton has developed root system, high survival rate and fast growth rate, and can be cultivated into seedlings with a DBH of 5 to 6 cm in 3 to 4 years. Hokkaido boxwood grafted with silk cotton as rootstock has early crown and strong cold resistance of grafted seedlings.