Banksia, like other members of the Proteaceae family, will not tolerate the application of fertilizers or planting in soils that are high in phosphorus. Too high of a level will severely damage if not kill your plant. Typical bloom fertilizers will not work for plants of this family, since they generally have high phosphorus levels that would otherwise encourage flowering. Ideally, plant in virgin soil that has never had any fertilizer applied, amended with perlite or sand as necessary to increase drainage. Organic fertilizers such as kelp meal and alfalfa meal, both of which have (at most) trace levels of phosphorus, can be used at planting time; otherwise, no fertilizer is required or necessary for these plants to thrive.

Reply to this comment