Grevillea 'Robyn Gordon' is a vibrant and popular Australian native shrub, celebrated for its nearly year-round display of coral-pink to deep rose flower clusters. From a botanical perspective, successfully managing its size and maximizing its floral performance requires an understanding of its growth habits, energy allocation, and response to environmental cues. The following sections detail this care regimen from the plant's point of view.
As a cultivar, my growth pattern is to be a dense, spreading shrub, typically reaching 1.5 to 2 meters in both height and width. My energy is primarily directed towards two goals: vegetative growth (producing new stems and leaves) and reproductive growth (producing flowers). To favor flowering, you must help me manage this energy balance. I thrive in full sun; this abundant light is my primary energy source via photosynthesis. Without at least six hours of direct sun daily, my energy reserves will be insufficient, and I will prioritize survival (leaf production) over reproduction (flowering). Furthermore, I require excellent drainage. My roots are susceptible to fungal pathogens in waterlogged, heavy soils. Constantly soggy conditions stress my root system, reducing its efficiency in water and nutrient uptake, which directly compromises my overall vigor and flowering capacity.
Pruning is not merely about size control; it is a direct intervention in my growth cycle. I do not respond well to hard pruning into old, bare wood, as I often lack latent buds there and may fail to regenerate. Instead, the goal is to encourage a compact, bushy form by stimulating new growth from just below the cut. The best time to prune me is after a main flush of flowers has begun to fade. From my perspective, this timing is ideal because the major reproductive effort is complete. Use sharp, clean secateurs and employ the "tip-pruning" method. Focus on removing the tips of the branches, cutting back by about one-third to one-half of the new, soft growth. This action removes the apical bud, which produces hormones that suppress the growth of lateral buds. By removing it, you break this apical dominance, and I will respond by producing multiple new side shoots from the nodes just below your cut. This results in a denser, more floriferous shrub, as flowers are produced on this new wood.
My flowering strategy is closely linked to nutrient availability and mild environmental stress. I am adapted to low-phosphorus soils. High levels of phosphorus, common in general-purpose fertilizers, are toxic to my root system and will inhibit my ability to absorb other nutrients, ultimately reducing flowering and potentially causing leaf scorch and plant death. If you feel I need a nutrient boost, you must use a fertilizer specifically formulated for Australian native plants, as these are low in phosphorus. However, in many well-prepared soils, I may require little to no fertilizer. A light application of a low-phosphorus fertilizer in early spring can provide energy for the first major flowering flush. More critically, avoid over-watering. Allowing the soil to dry out somewhat between waterings creates a mild hydric stress. From an evolutionary standpoint, this signals a less-than-ideal time for vegetative expansion and can trigger a shift in energy towards reproduction—producing flowers to ensure the species' continuation. This combination of full sun, well-drained soil, and minimal phosphorus is the key to unlocking my spectacular floral display.
