Grevillea, a genus of evergreen shrubs and trees native to Australia, has evolved to thrive in diverse environments. From a plant's perspective, successful propagation from cuttings relies on mimicking natural conditions that trigger root development. Grevillea species produce lignotubers or basal shoots, which store energy and hormones to facilitate regeneration. When taking cuttings, you're essentially harnessing this natural resilience by encouraging adventitious root formation.
For optimal success, choose semi-hardwood cuttings (partially matured stems) from healthy parent plants. These cuttings balance flexibility and lignification, allowing efficient nutrient transport while resisting rot. Avoid overly woody or tender green growth. The ideal cutting should be 10–15 cm long with 2–3 leaf nodes, as these nodes contain meristematic tissue capable of producing roots. Remove flowers or buds to redirect energy toward root development.
From the plant's perspective, wounding the base of the cutting mimics natural damage, stimulating hormonal responses. Use a sterile knife to make a clean diagonal cut below a node and lightly scrape the lower 2 cm of the stem to expose the cambium layer. Dip the wounded end in a rooting hormone containing auxins (e.g., IBA), which replicate the plant's natural rooting signals. Remove lower leaves to reduce transpiration but retain a few upper leaves for photosynthesis.
Grevillea cuttings demand well-draining, low-fertility media to prevent rot while encouraging root exploration. A mix of coarse sand, perlite, and peat (1:1:1) replicates their native sandy soils. Maintain high humidity (70–80%) using a propagation dome or mist system to reduce water loss, as cuttings lack roots to replenish moisture. Temperature is critical: 18–24°C (64–75°F) mimics spring conditions, when Grevilleas naturally grow actively.
Provide bright, indirect light (50–70% shade) to support photosynthesis without overheating cuttings. Direct sunlight can scorch leaves or dry out the media. Water the medium lightly but consistently, keeping it moist like a wrung-out sponge. From the plant's view, alternating slight moisture stress with hydration encourages root growth as the cutting seeks water.
Roots typically emerge in 6–12 weeks. Gently tug the cutting after 4 weeks to check for resistance, indicating root formation. Avoid disturbing the cutting excessively, as fragile new roots are easily damaged. Once roots are 2–3 cm long, acclimate the cutting to lower humidity over 1–2 weeks to prepare it for transplanting.
Transplant rooted cuttings into individual pots with native-adapted soil (e.g., sandy loam). Water deeply but infrequently to encourage deep root growth, mirroring Grevillea's drought-tolerant nature. Shield young plants from extreme wind or sun for the first few months while they establish.
