Propagating blueberries using cuttings is an accessible method for home gardeners seeking to multiply their favorite varieties. Success relies heavily on selecting the correct type of wood and adhering to a precise schedule and technique. Understanding the differences in timing and care between the two primary cutting types is the first step toward establishing a healthy new blueberry bush.
Timing Based on Cutting Type: Hardwood vs. Softwood
The best time to take blueberry cuttings depends entirely on whether you use dormant, mature wood (hardwood) or new, actively growing wood (softwood). Hardwood cuttings, which are generally easier to handle, are taken during the plant’s dormant season, typically from late January through February. These cuttings are sourced from strong, one-year-old shoots that have received sufficient winter chilling, ensuring the plant is fully asleep before propagation begins.
Softwood cuttings are taken during the active growing season, usually in late spring or early summer (May or June), but sometimes as late as August depending on the region and cultivar. These cuttings are selected from the tips of the current season’s new growth, specifically when the stems are still somewhat flexible but have begun to develop a slightly woody texture. The ideal timing is when the first flush of growth has ceased and the terminal leaves are half-grown to nearly mature, avoiding wood that is too soft and succulent.
Softwood cuttings generally allow for rapid multiplication and may root faster, but they demand significantly more attention to humidity and moisture to prevent desiccation. Hardwood cuttings take three to four months to develop roots but are often preferred due to their resilience and simpler handling. The timing for both types must be precise, as taking cuttings too early or too late can substantially reduce the rooting success rate.
Preparing the Cuttings and Rooting Medium
Careful preparation is necessary to stimulate root development. Both hardwood and softwood cuttings are typically cut to a length of four to six inches, with the bottom cut made just below a node. For hardwood, the bottom cut is often made on a slant, while the top cut is made straight to distinguish orientation when planting.
Softwood cuttings require removing all but the top two or three leaves to reduce water loss through transpiration. Hardwood cuttings, being dormant, have no leaves, but any plump flower buds must be carefully removed, leaving only the smaller leaf buds. Applying a rooting hormone, which often contains indolebutyric acid (IBA), is a highly beneficial step that can improve rooting success and speed.
The rooting medium must be both porous and acidic, as blueberries require a low pH for nutrient uptake. A common and effective mixture combines equal parts milled peat moss and perlite or sand, ensuring excellent drainage while retaining moisture. The high peat content helps maintain the necessary acidic environment, and the mixture should be firmed slightly around the base of the cuttings to eliminate air pockets.
Maintaining the Rooting Environment
Successful rooting requires a controlled environment that balances warmth, light, and high humidity. Applying bottom heat to the rooting medium, aiming for a temperature around 70°F, can significantly accelerate root formation. This warmth stimulates cell division at the base of the cutting, promoting faster root growth.
Light must be bright but indirect to provide energy without causing the cuttings to overheat or wilt. Direct, intense sunlight should be avoided, especially for fragile softwood cuttings. Maintaining high humidity is paramount, as it prevents the cuttings from drying out before they can absorb water through newly formed roots.
High humidity is often achieved using a humidity dome, a plastic bag tented over the container, or an intermittent misting system. This moist environment also increases the risk of fungal diseases, so proper ventilation is necessary to allow for air exchange and prevent stagnant conditions. Root development typically takes between six to twelve weeks, depending on the cutting type and environmental conditions.
Acclimating and Transplanting Young Plants
The final stage involves preparing the newly rooted plants for life outside the protected rooting environment. Successful rooting is confirmed when the cutting resists a gentle tug, indicating a firm anchor, or when new, sustained shoot growth appears. Once roots are established, the young plants must undergo a hardening off period.
Hardening off involves slowly reducing the high humidity and increasing exposure to ambient garden conditions. The humidity dome or plastic covering should be removed gradually, perhaps for a few hours each day, over a period of about a week. This process toughens the plant tissue, reducing the shock when it is moved outdoors.
After acclimation, the rooted cuttings are ready to be transplanted into a larger nursery pot or a permanent location. The new container or planting site must be prepared with an acidic soil mixture, such as ericaceous compost or a blend enriched with peat moss, to ensure the plant’s long-term health. The young blueberry plant can remain in the pot for a full season before being planted into the field the following winter.