How to Care for Proteaceae (Protea)
Plant genera in the Protea family (“Proteaceae”) include Banksia (Australia), Grevillea (Australia), Hakea (Australia), Isopogon (Australia), Leucadendron (South Africa), Leucospermum (South Africa), Protea (South Africa). These plants in the Proteaceae share several requirements:
Need full sun, six hours or more. But are fine in the fog!
Are phosphorus intolerant and should not be fertilized.
Thrive in pots, and should be planted in Cactus Mix.
In the ground, prefer deep, infrequent watering. In pots, should not be allowed to go completely dry between watering.
Soil
These plants thrive in pots, where drainage and nutrient content can be controlled. We recommend Cactus Mix.
Plants in this family typically prefer sandy, rocky, acidic, low-nutrient soils. Coastal sandy soils tend to be well-drained, deficient in nutrients, and slightly acid. Our clay soils, however, are different. Many California soils are typically heavy clay or silt. They can be alkaline, higher in phosphorus, and poorly drained. When planting in the ground, amend the soil with rock for better drainage. Pumice or any agricultural-grade gravel will work.
Fertilizing
Refraining from fertilizing is a good bet. If needed, gardeners should use fertilizers with almost no phosphorus and low potassium. Apply at a low strength and infrequently. Try low-phosphorus and low-potassium fish emulsion. Cottonseed meal adds nitrogen and acidifies but has a slightly higher concentration of phosphorus. Applying chelated iron in the spring can also be helpful. Fertilizer with phosphorous will poison the plants and kill them.
When Proteaceae find phosphorus in the soli, the plant will become yellow and begin to fail. Unfortunately there is no solution to this problem, other than to move the plant. It is worth noting that any area that has received a lot of fetilizer such as an area where a lawn has been, might have residual fertilizer in the soil.
Pruning
Tip pruning or light pruning when young is also recommended for proteaceous plants. It helps to prolong the life of most in this group, and it increases plant vigor and better shape. However, don’t cut back more than one-third of the growth, and never cut back to older branches that have dropped their leaves. Most Proteaceae will not sprout from such hard pruning.
Water
Protea plants are drought-tolerant. All require less than average water. Many will thrive with little supplemental water once established, especially on the coast. Some will tolerate normal (moist) garden conditions, and most will not.
Proteaceous plants should not be used in highly watered areas such as near lawns, vegetable beds, or annual color beds.
Deep but infrequent watering during the dry season is best. Of course, this only applies to established plants. Plants in the ground less than two years and container plants of any age will require closer attention and timely watering.
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