I talk with horticulturist Sabina Fielding Smith about growing proteas, such as Protea neriifolia (the oleander-leafed protea) which comes from South Africa, and how the first thing you need is an open, sunny position with good drainage. They do well in poor soils, and many don’t mind salty, coastal areas but humidity will knock them around. If you are north of Brisbane they will prefer the cooler, drier inland regions. In southern Australia they’ll do really well in places where the soil is well drained and it’s not too frosty.
How to get the most out of your proteas
– Great drainage, so if you’ve got heavy clay soil, forget it. All Proteas love a sandy loam or open soil.
– Do test your soil pH as most Proteas need acidic soil with a pH below 6. That’s quite acidic.
– Full sun with good air movement. Because they keel over with humidity.
The more sun the more flowers for all proteas which means around 4-6 hours of direct sunlight, and that’s not dappled sunlight. Proteas won’t grow on south facing walls.
Mulch your proteas using a natural mulch such as bark or straw or leaves.
– Don’t disturb the plants roots when weeding. They have surface, matting roots that are easily damaged. This makes them very unlikely to survive transplanting, so choose your spot carefully.
– Proteas are pretty tough once they’re established. Water at least twice a week in the first summer, even daily when it’s really hot. You can gradually reduce this as the plant becomes established. Watering in the morning is best so there’s less humidity around the plant through the evening and night.
– After the first year, plants labelled ‘drought resistant’ don’t need much attention at all. The rest should be watered weekly during dry periods.
– Potted protea like a nice drink every day.
– Generally it is not necessary to feed proteas planted in the garden, unless your conditions are extremely severe, like by the coast in very sandy soil, or in Perth, or your proteas are growing in containers.
– Feed proteas by adding compost or a slow release fertiliser suitable for Australian natives, is a good idea as it will be low in phosphorus. Proteas are best grown away from plants you need to feed regularly with regular fertilisers.
– Proteas grown in pots will need feeding with a controlled release fertiliser that’s low in phosphorus.
– Proteas become untidy looking if you don’t at least prune off the flowers when they’ve finished. Removing flowering stems helps keep the bush compact and looking great. Always use sharp secateurs and cut off long flowering stems down low, near the base, which will encourage new bushy growth and more flowering stems for the next season. Tip prune young shrubs in spring and late summer. Mature plants can be pruned immediately after flowering, usually leaving 10cm of healthy stem.
Varieties – the King Pink protea, Protea cynaroides, has one of the largest flower heads in the protea family. Sue also recommends trying Protea ‘Frosted Fire’ and Protea ‘Pink Ice’ (Protea neriifolia x susannae). ‘Pink Ice’ has spectacular flowers fresh or dried. It’s probably the one you most see in floral displays.
How to solve problems with your Proteas
Why won’t my Protea flower?
Some possible reasons are:
– It’s too young – some take 3 years, and the king protea up to 6 years.
– It’s in the shade – proteas need sun all day to flower.
– It’s not had enough water during bud formation, so the buds have died.
Why did my Protea die?
Some possible reasons:
– overwatering of mature plants.
– unsuitable plant for the conditions, such as poor drainage and too much shade
– presence of root rot fungi (treat with Phosacid and do not replant proteas in this spot).
– unsuitable soil (like high pH) or inappropriate fertilisers. Do not use mushroom compost or all-purpose fertilisers in the garden. Proteas have special proteoid roots which are very adept at extracting phosphorus from the soil, so adding high P fertilisers can cause phosphorus toxicity.