Care for Protea Plants
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Protea Plants:
- Good drainage
- Prefer acidic soils (low pH)
- Not tolerate phosphorus fertilizer
- Prefer deep, infrequent watering
- Have showy flowers and/or foliage
- Most make excellent cut flowers
- Do better in nutrient-poor soils with minimal tilling or digging.
Sun & Climate:
Most Proteaceous plants want full sun, meaning five or more hours per day, and good air circulation. They tolerate marine layer fog and coastal winds quite well and are seen thriving in California’s coastal regions from north to
south. Dry offshore winds are also tolerated. Frost is a limiting factor, with certain varieties of Banksia, Leucadendron and Grevillea offering greatest tolerance of occasional freezing temperatures. (A few varieties of Grevillea and Banksia have even proven useful in the Pacific Northwest and the coastal Southeast US.) Plentiful rainfall, especially during the cool season, is tolerated well by these plants grown in well-drained soils.
Soil & Fertilizing:
Sandy, Rocky & Gravelly Soil
Our Proteaceae family plants typically prefer fast-draining, acidic, low-nutrient soils. These plants have evolved to thrive in very poor soils. Sandy and gravelly soils tend to be well-drained, and poor in nutrients; both these qualities
benefit our protea-family plants. Sandy soils found on the coast and gravelly, sandstone, or decomposed-granite soils on bluffs and in foothill areas
serve proteaceous plants well. One reason is that they can be amended to the advantage of these plants. Most often reducing soil pH can solve nutrition problems. The addition of acidifying products like aluminum sulfate can reduce the pH to the range most protea-family plants prefer, 3.5 to 6.5. Occasional light applications of phosphorus-free fertilizers, with a zero in the second number on
the package, e.g. 18-0-15, can enhance growth of plants if they appear weak (pale green or blemished foliage, stalled growth). The addition of iron chelate may be useful if performance remains poor even after acidifying and applying
fertilizer (with zero phosphorus.) If you are planting in a naturally poor, sandy, or gravelly soil, refraining from fertilizing is a good bet, especially if
the area has not been previously treated with phosphorus fertilizers (as where food or flowers have been grown)—in which case the smart choice is to choose a different planting location.
Clay Soil
Our clay soils, however, are different. Most California soils are typically heavy clay or silt, and can be alkaline (especially in the south and inland), high in phosphorus and poorly drained. (Sandy or gravelly soils can also be alkaline, especially inland.) This can create problems if certain requirements are ignored. When planting in the ground, amend the soil with rock for better drainage. Pumice or any kind of agricultural-grade gravel will work. These plants thrive in pots, where drainage and nutrient content can be controlled. We recommend a cactus mix
because it does not usually have wood components, which break down and release phosphorus. Gardeners should fertilize infrequently. Fish emulsion or cottonseed meal is good. Feeding with chelated iron and epsom salts in the spring can also be helpful. Again, fertilizer with phosphorus will poison the plants and may kill them.
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. Many Proteaceae will achieve a tree-like look if left unpruned, or can be pruned routinely for a more bushy look. 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
These plants are drought-tolerant. All require less than average water. Many will thrive in the ground with little supplemental water once established, especially on the coast. Some will tolerate normal irrigated garden conditions
and most will not. Proteaceous plants should not be used in highly watered areas such as near lawns 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 judicious watering. In pots, these plants can go dry between waterings, but will not want to stay dry for very long. Some can get very
large even in a small pot, in which case they will then need more water.
In Pots
Many Proteaceae will thrive in pots. This is often the best way to enjoy them in areas of clay soil or gardens with constant ground moisture from irrigation or natural sources. Cactus mix should be used, and plants should be
well-watered until they are established. In a pot, with adequate water, they tolerate wind well, even cold foggy wind. Growing plants in this family can be highly rewarding. They are among the showiest and most ornate of all plants
when in bloom. They make excellent cut flowers and have few natural pests or diseases yet are very attractive to hummingbirds. Try them out and enjoy.
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