Introduction to Proteaceae

It was Carl Linnaeus, the famous Swedish botanist, who in 1735 classified the Proteas. Observing the variations in 24 historic engravings of what we now know as Leucadendron, Leucospermum, Mimetes and Protea, he named them all after the legendary Greek sea god Proteus, who could change his shape at will.

Proteas, Leucadendron and Leucospermum grow well in various parts of the world – South Africa, Australia, New Zealand, Israel, Chile, Portugal, Hawaii and small area of Southern and Northern California California.

These are Mediterranean climate plants that grow in areas with relatively low rainfall and high summer temperatures. Because of this trait these flowers are an excellent choice in areas where water is at a premium. The flowers have a long shelf life and therefore are in high demand for floral arrangements. Planting these flowers gives you the opportunity to participate in this emerging market, and add value to your property.

Selection of a Variety

In planting Proteas, Leucadendron and Leucospermum there is only one variable that can be changed. Your soil is fixed and can be only slightly modified by the use of fertilizers, mulch and compost. Climate cannot be changed much, although adding irrigation systems can control watering. Wind and shade are constraints you either have to live with or do without. So the only option available is to select the appropriate variety - ones that will grow where you live.

Nursery Plants

All plants are bench grown in a soilless media with no ground contact. Water molds, such as Phytophora, are soil borne and our nursery practices exclude contamination.

Growing Conditions

Proteas do best in a full sun location with good air movement around the plants and cool nights. Aadequate water drainage is the most critical factor in growing Protea; if the soil drains well, good results can usually be achieved. Planting Protea on slopes hills or on slightly elevated mounds is beneficial, because water runoff decreases drainage problems.

Diseases

Like most living things, there are a number of diseases that can harm Proteas, Leucadendron and Leucospermum. Phytophthora root rot (aka ‘Sudden Death Syndrome’) is the most common root disease contracted by these plants. This is a water-borne spore that multiplies very rapidly in wet soils at temperatures above 70°F. This is one of the reasons why these plants do well in winter rainfall regions. Over watering during the hot summer months can increase the risk of Phytophthora root rot. Botrytis (grey mold) is common to Proteas and may be found on the leaves and flowers during the cool spring.

Proteas, Leucadendron and Leucospermum are also susceptible to fungal disease. Good air movement around the plants usually takes care of this. If necessary, a chemical fungicide can be applied.

Pests

Mites, thrips and some spider species can become a serious problem on many varieties of plants. Control is by the occasional application of insecticides.

Ants, squirrels, gophers, rabbits, rats and mice are problematic to new plants and the best efforts should be used to control these pests. Established plants are generally not threatened.

Watering

Proteas need approximately 1/6th of the amount of water compared to avocados. In today’s changing times with water shortages and irrigation cut backs for agricultural use, there is no better time to plant Proteas. The field is laid out and the drip irrigation system installed prior to planting. Mature plants need water twice a week in summer for approximately 3 hours. Water at a very slow drip (two gallon per hour pressure compensated drippers) for two to three hours, depending on the weather and growth stage of the plants. The roots of the plants receive water but the foliage stays dry.

Fertilizer

Proteas are very light feeders. The plants are damaged by too much phosphorous in the fertilizer. Nitrogen fertilizer as soluble ammonium sulfate beginning in the second/third year is injected through the drip irrigation system. Fertilizer is applied in the spring and fall. Approximately 60 pounds of Nitrogen (N) fertilizer is applied per acre. Organic fertilizer can be used if desired to comply with the California Department of Agriculture Organic Program (ORG100-RF).

Pruning

Pruning is necessary for flower development. Pruning in the first three years consist of pinching out or cutting the terminals. Once the plant reaches maturity, pruning is incorporated with harvesting of the flowers.