How to Grow Blackberries from Cuttings
Blackberries, sometimes known as brambles, are very popular because of their sweet and slightly tart flavor. However, rather than buying them from shops, growing them in one’s own garden lets one enjoy plenty of freshly picked blackberries without a lot of effort. Especially if one lives in the U.S. Department of Agriculture plant hardiness zones 3 to 9 to which blackberries are hardy, they can have their blackberry plants thrive well and give big yields.
Blackberries are also easy to grow and maintain. Although there are multiple methods of planting blackberries, planting blackberry cuttings is perhaps the most reliable method of propagation if one takes softwood cuttings in early spring from offshoot growth.
The cuttings will root even more quickly if they are treated with root hormone. One should keep the planted cuttings in cool and humid conditions. But for their first summer, they should be grown in containers to allow a strong root system to develop before transplanting the plants in the fall.
Published: October 8, 2021.
Preparation to Plant in Containers
Before collecting blackberry cuttings for propagation, one should prepare the rooting container. They should fill 8-inch containers with a mixture of perlite, milled peat, and coarse sand in equal amounts. One can even use coir in place of peat.
Then they should water the mixture thoroughly so as to saturate it completely. Excess water should be removed by pressing the surface gently. Then the mixture should be allowed to drain for 10 minutes.
Now the grower should make a 4-inch deep hole in the middle of it to plant the cuttings.
To grow blackberries from cuttings, one should first find a healthy blackberry plant and then a young, 6-inch tall offshoot near its edge. Then they should dig down 2 inches around that offshoot.
This will expose the subterranean pale portion of the stem. Now they should separate the cutting 2 inches underground with a sharp utility knife.
Alternatively, one can even cut a healthy green growth at the top of the plant with a few leaves on it. In any case, one should avoid taking cuttings from hard, woody canes. The cutting should be firm and succulent and should be 5 to 8 inches long.
The gardener should wash the cutting (if taken from the base) right after severing it to remove any soil. All leaves too should be removed, except 5-6 at the tip.
Although it’s not absolutely necessary, IBA rooting hormone talc can be applied to the severed end of the cutting.
The excess powder should be removed by tapping the stem lightly. No usage of rooting hormone reduces the chances of success.
Now the grower should insert the cutting into the prepared planting hole and fill the remaining space in the hole with the mixture, and press it lightly against the stem.
Note: Some growers prefer to place the cutting first in a glass of water left in a warm, sunny, but protected spot and change the water every 2-3 days. New roots will develop in around a month and once they grow long enough to support the plant, the cuttings are transferred to soil.
Where to Place?
The grower should place the potted cutting outdoors in a shaded cold frame. The ventilation conduits on the cold frame should be kept open to facilitate air circulation and to prevent the temperature from increasing too much.
The grower should spray water on their cutting twice daily so as to keep the leaves cool and hydrated. Also, they should check the moisture level in the potting mixture and if it feels dry in the top inch, they should water it.
However, excessive watering should be avoided because the cuttings can rot in soggy soil.
After 3 Weeks
The grower should check the cuttings after 3 weeks by gently tugging them at the base level. If they feel resistance, it’s an indication of successful rooting. In that case, they should move the container to a shaded spot in the garden.
The blackberry cutting becomes eligible for transplantation 2 months after it roots. The grower should shift it to a 1-gallon container. This time the mixture should be of equal parts of compost, coarse sand, and loam.
The grower should place this container in a lightly shaded spot during the summer. They should water it 2-inch deep every 5 to 7 days, or whenever they find the growing mixture drying out in the top 2 inches.
Acclimating to Direct Sun
During the summer, the grower should acclimatize the blackberry plant to the direct sun.
They should place the plant in direct sun for an increasing amount of time every day until it develops the ability to stand full sun for 8 hours without burning.
Transplanting into Ground
Once the plant gets acclimated to full sun, the gardener can move it to a permanent location in their garden during mid-fall i.e. around late October.
The soil should be acidic and fast-draining and the plant should be provided with support to facilitate vertical growth.
Blackberry plants can also be grown from root cuttings.
Root cuttings should be 3 to 6 inches long and are taken in the fall i.e. during the dormancy period. These cuttings typically need cold storage for around 3 weeks, especially if the plants have larger roots. The gardener should make the cuts closest to the crown and an angled cut a little further.
Once the gardener takes these cuttings, they should bundle them together (with similar cuts together on both ends) and should cold store them at around 40°F (4°C) in the refrigerator or outdoors in a dry area.
After this cold storage period, the cuttings should be planted in the same way as that of stem cuttings with their straight ends inserted into the moist perlite-milled peat-coarse sand mixture.
If the roots of the parent plant are small, only small i.e. 2-inch sections should be taken and should be placed horizontally over the moist sand-peat mixture and should be lightly covered. Then they should be covered in clear plastic and placed in a shady location until new shoots emerge.
Once all the cuttings are rooted, they can be planted into the garden.
It’s essential to prune blackberry plants so as to avoid an overgrown, tangled mess.
Pruning can be done in spring. Canes that are too long should be lightly pruned to make them more manageable. Vertical canes should also be pruned so as to keep control over them and make the plant look compact.
Once fall arrives, the gardener should prune canes that produced berries. They should cut these canes to the ground so that that the plant can turn all its vigor towards new shoots that will fruit the next year.
Note: Gardeners should wear thick gloves while pruning blackberries as the plants have sharp thorns if one has planted a thorny variety.
It’s easy to know when to harvest blackberries. These tiny berries will first be green, then they will turn red and then black. Once they turn deep purplish-black, they are ready to harvest. Usually from late spring to early fall is the harvest time for blackberries.
One should then hold a berry between their thumb and forefinger and just twist it – it should be easily detached from the stem.