When Does the Plum Tree of the Rose Family Bloom and Bear Fruit, How to Prune It, and What Treatments to Use After Flowering to Protect Blooms and Fruit
The plum tree, also known as the cherry plum, is a common fruit tree and a deciduous small tree that can reach a height of 8 m; it is mostly propagated by grafting onto wild peach rootstock, and can also be propagated from cuttings.When does the plum tree usually bloom and bear fruit? When should it be pruned? What treatments should be sprayed after flowering to protect blooms and fruit?
When does the plum tree usually bloom and bear fruit?
Flowering:
The plum flowering period is in April. The flowers usually grow 3 together; the pedicel is 1-2 cm and usually hairless; the flower diameter is 1.5-2.2 cm; the hypanthium is bell-shaped; the sepals are oblong-ovate, about 5 mm long, with an acute or rounded-obtuse apex, sparsely toothed margins, and nearly equal in length to the hypanthium; both the outside of the hypanthium and the sepals are hairless, while the inside is sparsely pubescent at the base of the hypanthium; the petals are white, oblong-obovate, with an erose apex and a wedge-shaped base, with distinct purple veins, bearing a short claw, attached at the edge of the hypanthium, and 2-3 times longer than the hypanthium; the stamens are numerous, with filaments of unequal length, arranged in 2 irregular whorls, shorter than the petals; the pistil is 1, the stigma is disc-shaped, and the style is slightly longer than the stamens.
Fruiting:
The plum tree bears fruit in 3 years. Depending on tree age, the annual fruit yield also varies.
Plum trees generally begin bearing fruit in the second year after planting (leaving 3-5 fruits per tree); trees aged 3-5 years are left with 10-20 jin of fruit per tree; in full fruit-bearing period, depending on the tree's growth vigor, 50-80 jin of fruit can be left, or even more than 100 jin.
In addition, during the first 3-4 years after planting, the focus should be on promoting tree development and cultivating a high-yielding framework. During the full fruit-bearing period, pay attention to coordinating the relationship between yield and fruit quality, to avoid the phenomenon of high yield without high returns.
When should the plum tree be pruned?
The best times to prune a plum tree are as follows:
1. Young tree stage. During the young tree stage, growth is vigorous and strong branches form very easily. The main task of pruning is shaping and expanding the canopy, both to cultivate a good tree structure and to take early yield into account. Therefore, pruning should be light rather than heavy, mainly by thinning, moderating and summer bud removal and pinching. Newly planted seedlings are cut back at 60-80 cm; the sprouted branches are retained purposefully, and when the branches grow to 80 cm they are pinched, while temporary branches are pinched at 60 cm, to promote medium and short branches and form fruiting branches.
2. Fruiting stage. Plums planted for 2-3 years will soon flower and bear fruit, forming a yield. The purpose of pruning is to continue good shaping, expand the canopy, and cultivate as many fruiting branch groups as possible. During winter pruning, cut back the main branches at each level at plump buds, and thin out upright branches and crossing or overlapping branches. Continue good summer pruning, pinching, cutting back, and thinning. For vigorous shoots sprouting inside the canopy, as long as the position and direction are suitable, be careful to retain them and leave them unpruned to change branch vigor and form fruiting branches.
3. Full fruit-bearing stage. After shaping and pruning, the tree structure is fully formed, and this is the golden period of the plum tree's life. Yield rises year after year, branch growth decreases, and reproductive growth exceeds vegetative growth. In this period, on the basis of strengthening fertilizer and water management, pruning is used to control the outward movement of fruiting positions, cut back the main branches at each level, renew and cultivate fruiting branch groups, and thin out overly dense upright branches to improve internal light conditions. Keep the tree vigorous and extend the years of the full fruit-bearing stage.
4. Aging stage. As tree age increases, branch growth relatively decreases, and most branches are borne on the periphery and top. The main task is to renew and rejuvenate fruiting branch groups, using the method of removing weak ones and keeping strong ones, retracting branches that have fruited for years, cultivating and producing new branches, restoring tree vigor, increasing yield, and obtaining economic benefits.
What treatments should be sprayed after the plum tree flowers to protect blooms and fruit?
1. Spraying 300-fold boric acid or borax solution during the full flowering period of the plum tree can increase the fruit-setting rate.
2. Control of the plum sawfly: when the flower buds swell (just before flowering) and at the end of full flowering (80% of flowers fallen), spray 1000-fold cypermethrin at an interval of 10 days.
3. Control of the peach fruit borer: in late May, spray 1000-fold cypermethrin + 1500-fold diflubenzuron No. 3, and repeat the spray at an interval of 10 days.
4. Chemical treatment to protect blooms and fruit. Spray “Hualeduo” or “Quanshuguo” three times during the plum flowering period, that is, spray once when about 10% of flowers have opened, spray again at full flowering, and spray once more during the flower-falling period. During the plum flowering period, spring rain is often continuous, so be very careful to seize the time and spray quickly during breaks in the rain. Biological hormone treatments can also be used to protect blooms and fruit, with very notable results. For example, monopotassium phosphate, borax, 2,4-D, etc. can simply be sprayed onto the flowers. Biological hormone treatments for protecting blooms and fruit should also be sprayed three times for the best effect. Chemical protection of blooms and fruit is countless times stronger than natural pollination and artificial pollination. But be very careful about weather changes, seize sunny days and breaks in the rain to carry out chemical protection of blooms and fruit. During this period, to control fruit borers damaging plum flowers, just add an appropriate amount of insecticide when spraying the treatment.
5. Combine natural pollination with artificial pollination. Besides chemical protection of blooms and fruit, natural pollination and artificial pollination are also very important. Natural pollination is carried out by bees and butterflies. For artificial pollination, you can use a soft cloth strip or a chicken feather duster to gently tap and shake the flowers, without damaging them. You can also insert flowering branches of high-quality fruit trees into a water bottle and hang it on the tree, allowing bees, butterflies, and wind to carry out natural pollination. Combine artificial pollination with natural pollination. When the plum tree is in flowering period, appropriate natural pollination should be carried out, that is, releasing bees for pollination work, letting bees pollinate naturally, and paying attention to observation. When natural pollination is not effective, artificial pollination should be carried out. Combining these two methods is the guarantee for increasing future yield.