A Detailed Guide to Prickly Ash Tree Cultivation Techniques and Pruning Methods

Summary Heading cut: a light heading cut leaves only a small portion of the branch, a moderate heading cut is made at the sprouting point on the upper middle part of the spring shoot, a heavy heading cut is made on the lower middle part of the branch, and an extremely heavy heading cut is made at the weak-growing buds at the base of the branch. Thinning: remove weak branches and keep strong ones for concentrated pruning, cut vigorous branches to weaken branching, and prune large branches on a yearly basis. Renewal pruning: a small cut is thick and sturdy, a large cut weakens growth, and when renewing scaffold branches leave a nurse stub. Leaving a branch unpruned: upright branches are not suitable for leaving unpruned, vigorous growth is suitable for delayed pruning, and weak growth should be promptly headed back and renewal pruned.

I. Pruning and cultivation techniques for prickly ash trees

1. Heading cut

A heading cut is also called heading back. The longer the branch that is cut off, the stronger the bud at the cut, and the new shoots that grow out will also be longer and more robust. According to the length of the branch left after cutting, heading cuts are divided into the following four types:

(1) Light heading cut

A light heading cut leaves only a small portion of the branch. After cutting, it tends to grow into medium and short branches, the number of shoots per single branch is large, but most are relatively weak, which helps the mother branch grow faster and, to a certain extent, moderates the growth vigor of the branch.

(2) Moderate heading cut

A moderate heading cut is made at the upper middle position of the spring shoot, at the point full of buds. After cutting, it tends to grow into medium and long branches, the growth vigor of a single branch is relatively good, and the branching capacity is very high.

(3) Heavy heading cut

A heavy heading cut is made at the middle and lower part of the branch. After cutting, it tends to produce about 1-2 branches with good growth vigor. Although the growth vigor is relatively strong, the branching capacity is low and the total growth amount is not great.

(4) Extremely heavy heading cut

An extremely heavy heading cut is made down to the weaker-growing buds at the base of the branch. After cutting, it tends to sprout about 1-3 medium and short branches, with weak growth vigor and low branching capacity. For some sensitive prickly ash varieties, individual cuts may also sprout vigorous branches.

2. Thinning

Thinning is also called branch thinning. In practice, the method of removing weak branches and keeping strong ones is often used for concentrated pruning. This not only concentrates nutrients to enhance growth vigor, but also strengthens branch growth and development and increases prickly ash yield.

(1) After thinning, the mother branch is weakened to a certain extent, reducing the total growth amount of the tree. Therefore, we adopt the method of thinning vigorous branches to weaken nurse branches and promote flower bud formation, and thin strong branches to reduce the number of branches, so that the branches reach a balance point and the balance relationship among branches is regulated. In a year with a heavy crop, appropriately thin fruiting branches to prevent alternate bearing.

(2) When thinning larger branches, thinning should be carried out on a yearly basis. Excessive thinning will cause “opposite wounds” and weaken growth vigor. Note that thinning should start from the base, so the wound will heal more easily. However, if too long a stub is left, latent buds are likely to grow, so avoid forming excess water sprouts later, or even leaving a residual stub that leads to rot.

3. Renewal pruning

Renewal pruning is also called cutting back. Renewal pruning can lower the position of apical dominance, change the growth direction of branches, achieve the conditions for ventilation and light penetration, and prevent the crown from expanding too much. It can also shorten branch length and control branch growth.

(1) The cut of renewal pruning is generally relatively small. When the branch at the cut is thick and sturdy, it can enhance the growth of the branch at the cut.

(2) When the cut is relatively large, most of it should be cut away to weaken the growth of the branch at the cut.

(3) When renewal pruning scaffold branches, pay attention to leaving a nurse stub at the perennial part to avoid weakening the branch at the cut.

4. Leaving a branch unpruned

Leaving a branch unpruned is also called delayed pruning or long pruning. It has the effect of moderating the growth vigor of new shoots and reducing branching capacity. After being left unpruned, the number of long branches will increase noticeably and they will thicken.

(1) During the young growth stage, after oblique, horizontal and drooping branches are left unpruned, although there are many sprouts, overall the growth vigor of the resulting branches is poor. Upright branches on scaffold branches should not be left unpruned, otherwise the phenomenon of “trees growing on trees” will appear, affecting both tree shape and flower buds.

(2) After leaving a branch unpruned, no effect can be seen for the time being, and some take several years to show. Therefore, vigorous-growing varieties are suitable for delayed pruning, and after flower buds appear or after flowering and fruiting, they should be promptly cut back to cultivate fruiting branch groups. Weak-growing varieties are not suitable for delayed pruning, and excess branches should be promptly headed back and renewal pruned, otherwise they will age and affect yield.

II. Precautions for prickly ash pruning

1. When pruning prickly ash, ensure the cut is smooth and has a slope of more than 30 degrees to avoid water accumulation and stump rot.

2. Some growers with high prickly ash yields and large areas may not finish picking until mid-to-late July, and pruning at that time will affect the normal sprouting of branches and shoots the following year and reduce the next year's yield. Therefore, you can choose late June or early July to first cut off the large branches of the prickly ash tree, and then carefully prune the branches afterward.

3. In mid-July, the high-temperature summer drought period arrives. At this time, pruned prickly ash should preferably retain several leafy branch tips. The leaves can effectively regulate water evaporation, play a transpiration role in transporting fertilizer and water upward, promote the differentiation and sprouting of new branch tips, and ensure yield.