Everybody likes blueberries. Vaccinium is the genus that encompasses a variety of blueberry species. This report will focus on Vaccinium corymbosum, commonly found along the eastern US as the “New Jersey blueberry” or sometimes the “Highbush blueberry”. This is a species that can often be found out in the wilderness, but can also be propagated for planting at one’s home or other landscape.
http://upload.wikimedia.org/wikipedia/commons/1/17/Vaccinium_corymbosum%2801%29.jpg
Vaccinium corymbosum is not exactly a blueberry that one would produce on a large scale production setting for commercial use. These are the types of berries found in the forests and in backyards. Blueberries are remarkable plants in the sense that they have evolved to grow in rather unfavorable environmental conditions such as acidic soils and are able to reestablish quickly after forest fires. They are able to survive in this manner using a system of rhizomes to send up new plants quickly to outgrow competition and make use of new available nutrients.
The plant can achieve quite large sizes, anywhere from 6 to 12 feet if left unkempt. All of this plant matter allows for opportunity to propagate by cuttings. This plant is able to be propagated relatively easy by both soft and hardwood cuttings, though it is more frequently propagated by hardwood cuttings of the shoot system. Different species of Vaccinium are propagated by softwood cuttings simply because they root better in that stage of development. Softwood cuttings tend to root more easily but are more susceptible to dessication and thus require a great deal more care, including constant irrigation or mist system. If desired, alternate methods of propagation can be done, such as seed, tissue culture, or grafting. Propagation by grafting is not typically done as the blueberry bushes require pruning and the graft will likely be required to be cut out after only a few years. Tissue culture is done very infrequently but is effective to produce many plants relatively quickly. this practice requires strict sanitation and an able laboratory.
HOW IT’S DONE
Selecting a cutting: When the decision to propagate a blueberry bush by hardwood cutting, the ideal time to do so is the very beginning of spring, typically March. A healthy mother plant should be selected that is free of all disease and pests, as disease will be transferred to the new plant. Once a good mother plant is found, a branch should be taken that is from the previous year’s growth that is solid and woody. The branch should be cut from the basal area of the plant, should have few leaf buds, and if preferably no fruit buds, as they will interfere with vegetative growth. Select a branch that has a width of about 0.6 – 07 cm, or about the width of a pencil. Use sharp sterile shears to make a clean cut through the plant tissue, being careful not to damage the tissue by crushing it because this would interfere with root formation or maybe even prevent it. Cuts should be made so that the cutting is 12 – 30 inches. This long cutting, or “whip” can be used to make several new cuttings each of about 4 inches long. Each of these smaller cuttings should have the basal cut be just below a leaf bud if possible.
Rooting and soil Media: Now that cuttings have been obtained it is time to establish a root system to the plant may being to grow. Cuttings can be stored until you are ready to use them later. They can be stored from 35 – 40 degrees Fahrenheit with a very high humidity for several months. For most propagating purposes, an auxin rooting hormone of about 3,000 ppm is common practice to help the plant become established in the new media, however hardwood cuttings of Vaccinium corymbosum have proved to be relatively unresponsive to auxin treatments. Softwood cuttings however tend to root better with this sort of treatment. Rooting of hardwood cuttings may also be enhanced when a double basal wounding treatment is implemented. Do do this, a sharp knife is used to scape off a half inch to one inch of bark from both sides of the base of the cutting. This induces more adventitious root formation, and if auxin is used, will help the cutting absorb more of it. Cuttings can be directly potted about one inch deep into a moistened soil medium that is roughly 2:1 peat-mix to sand, has adequate water and nutrient capacity with an acidic pH of 5.5, remembering the plant’s natural habitat of acidic forest fire soil. If pH needs to be lowered, try using a sulfur compound from your local garden store to lower the pH to where it should be.
Cutting Care: Cuttings should be placed into the potting media about one inch deep below the surface, but still leaving two or three buds above the surface. The cuttings should remain in the greenhouse with enough water to prevent dessication, but not so much as to water log the soil; a thorough soaking about once a week should do along with the humidity levels remaining high. A constant temperature of 68-73 degrees Fahrenheit should be maintained. These plants enjoy large amounts of sunlight and some artificial light can be beneficial as well. During the summer months, after roots and foliage have been developing nicely, some fertilizers such as a 15-30-4 ratio of nitrogen, phosphorous, and potassium used about once a week should promote growth if desired. When winter months come around plants can continue to grow in the greenhouse to overwinter during the dormant period.
Transplanting: When spring comes finally comes around, the cuttings will be ready to be put outside in the desired location. If grown in the greenhouse during the winter months, the plants should be hardened off to reduce transplant shock. Transplant shock is a temporary slowing or stopping of development due to rapid change in environmental conditions and also slowed uptake of water with rapid transpiration. To harden off plants, watering should be reduced and temperatures should be lowered gradually at night to simulate outdoor conditions. Transplants still favor well drained and acidic soils. Fertilizers can be used if desired to help the new established plant.
Literature Cited:
Eck, Paul. Blueberry Science. New Brunswick: Rutgers UP, 1988. Print.
Strik, B., and C. Fisher. “Blueberry Propagation.” Northwest Berry & Grape Information Network. (2006): n. page. Web. 9 Feb. 2014. <http://berrygrape.org/blueberry-propagation/>.
Nesom, Guy. “Highbush Blueberry.” USDA.gov. United States Department of Agriculture, 26 7 2002. Web. 29 Jan 2014. http://webcache.googleusercontent.com/search?q=cache:NfPM53BpYYMJ:https://plants.usda.gov/factsheet/pdf/fs_vaco.pdf+&cd=1&hl=en&ct=clnk&gl=us
By: Liam Farrell
LMF5325@psu.edu