As a Grevillea, I must clarify from the outset that I am not truly a tree, but rather a woody shrub or small tree from the Proteaceae family. My growth indoors is a complex negotiation between my inherent nature and the environment you provide. My pace is not like a rapidly climbing ivy or a slow-growing cactus; it is moderate but entirely dependent on conditions.
In my native Australian habitat, with abundant sun and well-draining acidic soil, I can put on a substantial 1 to 2 feet of growth per year when young. However, the indoor environment is a world apart. Here, my growth will be considerably slower. You can expect a healthy, well-situated indoor Grevillea to grow approximately 6 to 12 inches annually. This rate is not steady; I will experience bursts of new growth, particularly in the spring and summer, followed by periods of rest or much slower development in the lower-light winter months.
My growth velocity is dictated by several non-negotiable factors. Light is the absolute most crucial. I am a sun-worshipper by nature. To photosynthesize efficiently and fuel my growth, I require a minimum of 6 hours of very bright, direct sunlight daily. A south-facing window is my ideal spot. Without this, I will become etiolated—stretching out weakly with sparse foliage—and my growth will slow to a crawl as I starve for energy.
Next is my soil and water. I demand exceptionally well-draining, acidic, and low-phosphorus soil. My roots are highly sensitive and will quickly succumb to root rot if left in moisture-retentive, standard potting mix. Waterlogged soil doesn't just stunt my growth; it kills me. Water me deeply only when the top inch of soil is dry, and always ensure excess water can drain away completely.
While I may start as a small potted plant, you must understand my potential. Even indoors, I can eventually reach heights of 6 to 8 feet or more if I am never pruned and conditions are perfect. This is why pruning is not just for shape but for management. Regular tip-pruning after flowering encourages a bushier, denser form and controls my vertical ascent. Furthermore, I am not a long-lived houseplant. Even with excellent care, the stresses of a containerized, artificial environment mean I may only thrive indoors for 5 to 7 years before I begin to decline, a fraction of my lifespan outdoors.
You will know I am growing well by the appearance of new, soft, often bronze-colored growth at the ends of my branches. This will gradually harden off and turn green. My unique spider-like flowers are the ultimate sign of my contentment, indicating that my energy needs are being met. Conversely, yellowing leaves can signal poor drainage or incorrect soil pH, leaf drop often points to overwatering or a sudden draft, and a complete lack of new growth signifies an urgent problem with my light or root health.
