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.
Diseases
Like most living things, there are a number of diseases that can harm Proteas, Leucadendron and Leucaspermum, 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 degree 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.
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.
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. Adequate 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.