Botanic Gardens Trust, Sydney, Australia

Growing proteas

Proteas

Proteas are native to southern Africa and belong to the same family of plants (the family Proteaceae) as the Australian banksias, grevilleas and waratahs. The name ‘protea’ is commonly used to refer not only to plants in the genus Protea, but also to plants in two other genera from southern Africa: Leucadendron and Leucospermum.

The family Proteaceae is an ancient family of plants with a Gondwanan ancestry - it was one of the earliest groups of flowering plants and was able to disperse and diversify throughout Gondwana before the supercontinent disintegrated. With about 1600 species, it is one of the plant groups which now dominate the southern hemisphere floras.

Proteas at the Blue Mountains Botanic Garden, Mount Tomah

Proteas are a feature of the Southern Hemisphere plant display below the Visitor Centre at the Blue Mountains Botanic Garden. The best time of the year to see the proteas in bloom is late autumn-winter. Proteas can be grown successfully in Australian conditions - even though they are native to southern Africa. Protea plants can be purchased at the Blue Mountains Botanic Garden Shop and this fact sheet gives clues on how to grow these fascinating and beautiful plants.

Selecting proteas

  • seek advice from your local nursery on which type of protea grows best in your area
  • select a healthy-looking plant

Soil requirements

  • most proteas prefer soils that are well-drained and acidic: they don’t like wet feet!
  • proteas will generally not tolerate heavy clay soils as they need good drainage for healthy root growth
  • if you have a garden with heavy or clay soil, consider improving the drainage by using a free draining garden mix and either creating a raised garden bed (minimum height 30-45 cm) or installing underground drainage pipes

Planting proteas

  • the best time for planting in Australian climatic conditions is either autumn or spring
  • most proteas flower best when planted in full sun, although some varieties will tolerate a bit of shade
  • allow plenty of space between plants for air to circulate and for plants to grow
  • don’t plant any proteas deeper than the surface level in the pot

Fertilising proteas

  • in nature most proteas grow in soils that are low in nutrients, so they can be harmed by fertilisers which contain normal levels of phosphorus
  • it is best not to use any fertiliser when planting out proteas - they have a specially adapted system of fine roots (called ‘proteoid’ roots) which will develop naturally to seek out available nutrients in the soil
  • if you feel it necessary to fertilise proteas in the early stages of growth then use an Australian native plant fertiliser - either a very mild solution of a soluble fertiliser or coated slow release pellets, with low or zero phosphorus
  • proteas may need fertilising when they are reaching maturity, especially if the type of soil in your garden is free draining, e.g. sandy loam

Watering proteas

  • good drainage is essential
  • protea root systems must be kept moist, but not too wet, until the plants are well established (this can be up to 18 months or more)
  • frequency of watering will depend on soil type and climatic conditions
  • mature proteas only require deep watering once a week during dry spells, or once a fortnight during a dry winter

Mulching and weed control

  • natural mulches - such as leaves, wood chips or general shredded garden waste, which have been aged - are probably the best because they look good in the garden and they help to retain moisture
  • avoid fresh young mulching materials which tend to draw nitrogen out of the soil as they rot and which can harbour harmful fungi
  • keep mulching materials away from protea stems as this may cause them to rot
  • a good mulch layer at least 10 cm thick, together with careful hand weeding (being careful not to disturb the surface roots) will keep weeds under control

Pruning proteas

  • proteas can be lightly pruned during the first 12 months to give a good shape and to help them establish resistance to strong winds
  • mature proteas should not be severely pruned as this may permanently damage them

Cut flowers

  • cut the flower stems as long as possible, ensuring that there is foliage remaining on the stem below the cut, and remove foliage from the lower part of the flower stems before placing in water
  • fresh cut flowers can be maintained by regularly cutting 1-2 cm off the bottom of the stems and changing the water
  • for best results add a quarter teaspoon of household bleach to every litre of fresh water
  • for dried arrangements flowers can be dried by hanging them upside down in a dark place where there is some air circulation - this helps to retain more colour in the blooms and helps prevent the growth of mould

Proteas as pot plants

  • it is possible to grow the smaller varieties of proteas in containers
  • use a coarse well-drained native potting mix, keep the plants in a sunny position with plenty of air circulation and keep the root system cool
  • do no over-fertilise or let the container dry out

Protea

Blue Mountains Botanic Garden