|I have an Ivanhoe Grevelia and the leaves are curling and drying up. I have it in full sun, water deeply and infrequently and fertilize on occasion. Can you tell me what I can do to improve the health of this plant?
|Grevillea is a native of Australia as does best in poor, rocky soils in full sun with little water. Curling, drying leaves could indicate over-watering or over-fertilizing. Like most members of the Protea family, Grevilleas have a distinctive root system ("proteoid roots") consisting of tight groupings of many small "rootlets". These are believed to enable the plants to more efficiently take up nutrients from the nutrient-deficient soils where many of the species occur naturally. In cultivation this means that the plants can be adversely affected by fertilizers, particularly phosphorus. It is generally recommended that grevilleas and other Proteaceae be fertilized only with low-phosphorus, slow-release fertilizers or not be fertilized at all.
You might also inspect the curling leaves with a magnifying glass. Spider mites may be feeding on the foliage. They can cause stippling, or dull coloring where they've fed. If you find spider mites (look closely for webbing, as well), you can either prune off the affected stems or knock them down with an insecticide.
Best wishes with your Grevillea.