From my perspective as a Grevillea, sunlight is my primary source of energy. I require a full day of direct, unfiltered sun to fuel the immense metabolic effort of producing my intricate and nectar-rich blooms. A minimum of six hours is essential, but I truly thrive with eight or more. When planted in partial or dappled shade, my energy production slows. My resources become limited, and I must prioritize survival over reproduction. This means I will direct my energy into growing foliage and roots rather than forming flower buds. To see the most spectacular display of my blooms, place me where I can bask in the sun's rays all day long.
Many gardeners believe that more fertilizer leads to more flowers, but for me, that is a dangerous misconception. I am a member of the Proteaceae family, and my roots are exceptionally sensitive to high levels of phosphorus. Standard fertilizers can be toxic to me, causing root burn and preventing me from absorbing the nutrients I actually need. Instead of promoting blooms, this will cause me stress and ill health. If you must feed me, seek out a native plant-specific fertilizer that is low in phosphorus or has a zero phosphorus formulation. A light application in early spring is all I require. Too much, and you will do more harm than good.
The way you trim me has a direct impact on my flowering. My blooms develop on new, season's growth. If you prune me heavily in winter, you are removing the wood that would have produced my spring flowers. The ideal time to shape me is immediately after a flush of flowers has finished. This gives me ample time to produce new branches, which will then harden off and develop the next round of flower buds. When you prune, focus on tip-pruning and removing spent flower heads. This signals to me that I should channel my energy into creating new lateral shoots, which are the sites where future blooms will emerge. Avoid cutting back into old, bare wood, as I may not regenerate from these points.
My roots are not just sensitive to phosphorus; they are also highly susceptible to root rot fungi if left sitting in waterlogged soil. I demand exceptionally well-draining soil. Heavy, clay-based soils are my nemesis. If you are planting me, amend the soil heavily with gravel, sand, and organic matter like native compost to create a loose, free-draining mound. For potted specimens, a native potting mix is non-negotiable. Constantly wet feet cause my roots to suffocate and die, putting me under extreme stress. A stressed plant focuses solely on survival and will not invest its limited resources in blooming.
While I need regular watering to get established, I am inherently drought-adapted. Once my root system is developed, I prefer deep but infrequent watering. Constant moisture keeps my roots too comfortable and encourages lush leafy growth at the expense of flowers. Allowing the soil to dry out somewhat between waterings mimics my natural Australian habitat and creates a mild, strategic stress. This slight stress is a signal for me to reproduce, prompting me to produce a profusion of blooms to ensure my genetic legacy continues. Overwatering is a common reason for my lack of flowers.
