How to Graft or Clone Blueberries
Blueberries (Vaccinium spp.) are a popular home garden plant for the healthful berries they produce, as well as their ornamental characteristics. They can be grown in U.S. Department of Agriculture plant hardiness zones 3 to 10, though not all varieties are suitable for all zones. However, the same propagation methods can be used on any type of blueberry. Unlike most fruit trees, which require the relatively complex procedure of grafting to reproduce them, blueberries are cloned by the simple process of taking softwood cuttings.
Locate a healthy, disease-free blueberry bush that is known to produce good quality fruit. Select a long straight stem and remove it using sterilized garden pruners. Remove the leaves and divide the stem into cuttings of 4 to 6 inches in length. Older wood that is over one-half inch in diameter should be discarded, as well as wood from the tip of the branch that is less than one-eighth inch in diameter. The best results will be from wood that is still green, known as “softwood.”
Mix equal parts peat moss and perlite for use as a rooting medium and fill the pots. These materials are usually available in garden centers. Wet the medium thoroughly and tamp gently to remove air pockets.
Place up to four cuttings in each pot, being sure that they are oriented in the same direction as they were on the plant they came from. Upside down cuttings will not root. It is important that at least one leaf “node” is below the rooting medium and one is above. The leaf nodes are the small protrusions along the stem that the leaves grow from. This is important because roots will form at any nodes in the rooting medium and new leaves will grow from the upper nodes.
Cut the top 4 inches off the plastic bottle and place the bottom section upside down over the cuttings inside each pot. Push the edge of the bottle down into the rooting medium to form an enclosure over the cuttings like a tiny greenhouse. This holds moisture in the air around the cuttings to prevent them from drying out while they are forming roots. Locate the pots in a warm sunny window, but away from extreme afternoon heat.
Mist the cuttings once a day and check for growth. They should start to push out new leaves within two to three weeks. If the top of the cutting turns brown and appears dead, it should be removed. This will likely occur with at least 20 to 30 percent of the cuttings, even under the best conditions.
Transplant cuttings to individual gallon size pots after 1 to 2 inches of new growth has occurred from the top of the stem. The new top growth indicates that sufficient roots have developed to sustain the plant; this usually occurs within one to three months. Allow the new plants to develop for a full growing season before planting in a permanent location in the garden.
How to Graft or Clone Blueberries. Blueberries (Vaccinium spp.) are a popular home garden plant for the healthful berries they produce, as well as their ornamental characteristics. They can be grown in U.S. Department of Agriculture plant hardiness zones 3 to 10, though not all varieties are suitable for all zones. …
Blueberries usually are propagated from softwood or hardwood cuttings by cutting selected twigs from healthy, disease-free mother plants. Cuttings are placed in propagation beds in a medium that holds moisture well but also allows adequate aeration.
Softwood Cuttings – Take softwood cuttings (4 inches to 5 inches long) in late spring from the tips of the current season’s growth. Collect these cuttings when stems have developed woody tissue but are still somewhat flexible and terminal leaves are half-grown to almost mature. Cuttings taken too early (terminal leaves very succulent, stems very flexible) may readily wilt. Cuttings taken too late (mature leaves, second flush of growth initiated), may poorly root. Rooting usually is more successful when cuttings are taken from the first flush of spring growth. However, cuttings can be collected from growth flushes occurring later in the growing season.
Take cuttings from the upper part of the mother plant. Use sharp, clean pruning shears or knives disinfected in a solution of 1 part household bleach to 5 parts water. Remove lower leaves leaving two or three terminal leaves. Don’t allow cuttings to dry; keep them moist and cool after collection. Place cuttings in the propagation bed, under mist, as soon as possible at a depth of one-half to two-thirds of their length.
Hardwood Cuttings – Hardwood cuttings are taken during the dormant season after sufficient chilling has occurred, usually late January through February. Collect strong, healthy shoots or “whips” (usually 12 inches to 36 inches long) that grew the previous summer. Divide these “whips” into sections 5 inches to 6 inches long with a sharp knife or a bench saw with a fine blade. If the terminal of the shoot contains flower buds, remove the flower buds or discard the tip.
Insert cuttings into the propagation medium from one-half to two-thirds of their length with one shoot bud exposed. Keep the propagation beds moist, but be careful not to use too much water. Water hardwood cuttings with a sprinkler until they start growing leaves, then mist-water the cuttings until they are rooted.
After cuttings are rooted, apply a dilute complete liquid fertilizer weekly. Plants can remain in the propagation bed until winter, when they should be transplanted into pots or nursery beds and held them for one year. The plants should be large enough for field planting the next winter.
Propagation beds need to be well-drained, under shade cloth (40 percent to 70 percent shade), and have adequate ventilation. Avoid excessive wind movement that may interfere with mist control.
Propagation Media – A medium that retains moisture well but allows aeration is necessary. Media containing various propagation mixtures of coarse sand, ground pine bark, perlite, sawdust, and peat moss have proven satisfactory. A good rooting medium recipe is a mixtures of coarse sand, ground pine bark, and peat moss (1:1:1) or perlite and peat moss (1:1).
Mist System – The mist system should keep the media uniformly moist but not soggy. If only a few drops of water can be squeezed from a handful of media, the amount of moisture is probably correct. An intermittent-mist system is needed to keep the humidity around the cutting near 100 percent, preventing wilting, and keep the medium moist. Starting with a porous medium that holds moisture well, adjust the mist intervals to maintain turgid (non-wilted) leaves and high humidity. Frequent (2 minutes to 10 minutes) short misting intervals (2 seconds to 10 seconds) are recommended.
Important Considerations One of the major problems with collecting propagation wood from other grower’s fields is contamination of cutting wood, either with off-type cultivars or with diseases. Many farms have a small percentage of off-type cultivars mixed with their primary cultivars. This can create serious problems at harvest time if the off-type ripens at a different time than the primary cultivar. The off-type cultivar may also be of lower quality than the primary cultivar, and thus lower the grade of the packed fruit. When available, always purchase virus-tested, true-to-type plants to serve as propagation sources.
Diseases such as viruses may be transmitted via cutting wood taken from infected bushes. Although distribution of blueberry viruses appears to be limited at this time in the Southeastern United States, avoid propagation from plants that have odd-looking or stunted foliage. They may be harboring a virus that could reduce yields. The Blueberry Stunt phytoplasma is common in North Carolina, and can be transmitted via propagation. Stem Canker is a fungal disease causing swollen cankers that eventually kill infected canes. Avoid collecting cutting wood from infected plants.
Avoiding off-type or diseased cuttings during propagation is best accomplished by scouting the source field during the growing season prior to taking cuttings. Specific rows or individual bushes of uniform, healthy source plants can be most easily found and mapped during bloom and harvest, excluding visibly diseased or off-type bushes. This pre-propagation scouting is especially necessary when growers are planning to take dormant, hardwood cuttings, since off-type or diseased bushes may not be easily identifiable in winter. Once your own field is established, you will be able to identify and remove offtype bushes over time and avoid contamination of your propagation material.
- Braswell, John H. Establishment and Maintenance of Blueberries. Retrieved 14 June 2010.
- Krewer, Gerard and Bill Cline. Bluberry Propagation Suggestions. Retrieved 16 June 2010.
Blueberry Propagation Blueberries usually are propagated from softwood or hardwood cuttings by cutting selected twigs from healthy, disease-free mother plants. Cuttings are placed in propagation