The king protea (Protea cynaroides) – the South African national flower, and a fantastic, patriotic addition to the garden. However, many Proteas need a little extra attention to detail. We’ve put together some information on growing proteas in KZN:
Your proteas should be planted in well drained soils. If your soil is heavy, prepare the bed by mixing very well decomposed compost into the soil before making the planting hole. Your compost must be low in phosphates. Simply filling your planting hole with compost is not the right thing to do. The compost will form a reservoir for water to stand in and this increases the chance of root rot of your protea. In heavy soils, mix very well decomposed compost which is low in phosphates into the soil before making the planting hole. Simply filling the hole with compost is not a good idea as this only forms a reservoir for water to stand in which will increase the chances of root rot. Mounding heavy soil to improve drainage is a good idea, as is incorporating some gypsum to break up they clay. Most varieties of proteas need a slightly acid soil.
Plant your proteas in a position with full sunlight. They need lots of sunshine in order to produce flowers.
Protea plants need to be well established before they can be truly drought tolerant. Directly after planting, your proteas should be watered in thoroughly. After that, they need to be watered so as to maintain soil moisture without causing the soil to be water logged. This means that on most loamy soils, you’ll need to water twice or three times a week. In sandy soils with good drainage and in pots with the correct potting mix, plants should be watered daily. Proteas prefer drip irrigation to overhead irrigation, as wet foliage increases the disease risk. Once your plants are established, they can survive without any water or maybe a drink once a week in the heat of summer if water is available.
Once fully established, most proteas can tolerate some frost, but the flowers may be damaged. If frost is a problem in your area, make sure you only plant out your protea in late spring, once frost is no longer a threat. During the first two years of your protea plant, protect them against frost by covering them during the night.
A thick layer of bark, straw or leaves can be placed around plants to conserve soil water, keep the roots cool and reduce weed pressure.
Proteas do not like competition and the area around your proteas should be kept free of weeds. Avoid cultivation around your plants. It’s best to pull weeds out by hand when they are still small. Avoid unnecessary root disturbance to your proteas by holding the soil around the weed down. Place one hand flat on the ground around the weed and pull it out with the other hand. If you feel that pulling out the weed will up-root your protea, rather cut the weed off at ground level with a pair of secateurs.
To enjoy a protea plant with a good shape for a long time it is necessary to do some basic pruning. Remove the flowers, either for the vase or after they have flowered, by cutting back leaving 10-15cm of each stem on the plant. Remove some of the thin and curly stems in the center of the bush to improve light penetration and increase air movement through the plant, thereby reducing pest and disease risk. Remove shoots lying on the ground or growing downwards towards the ground. Prune your plants in late winter the first year after planting and then every year after flowering. Avoid cutting back into older wood, especially if the leaves are not healthy green.
Proteas are adapted to growing in very nutrient poor soils. Their root systems are capable of extracting the food they need from the soil. It’s important to note that proteas are very sensitive to applied fertilizers. Do not apply bone meal, phosphates, mushroom compost, chicken manure or any other manure for that matter. Most composts have high levels of nitrates, ammonium or phosphates and it is just not worth the risk. Once established in the ground your protea will look after itself. The best thing you can do is not to feed it at all.
Proteas in the garden can give you a very rewarding cut-flower supply for the vase in your home. Strip the leaves off the part of the stem that will be in the vase. The flowers are very thirsty and vases should be topped up with fresh water every day. Use a clean vase and add a tablespoon of household bleach to each litre of water in the vase. Display your arrangement in a cool place out of direct sunlight for the longest vase life.