Flower lovers cheer for the exotic ‘King Protea’

By Carol Nelson, Southside Master Gardener

The annual Rose Parade winding down Colorado Blvd. in Pasadena, CA on New Year’s Day is a flower enthusiast’s dream. Every float is covered with lush blooms and greenery from around the world, as well as natural materials such as coconut fibers, seeds and coffee grounds. The oldest (and certainly one of the showiest) flower on display in the 2020 parade was the King Protea, Protea cynaroides, the national flower of South Africa.
The protea family (Proteaceae) includes over 1500 species and is believed to be about 100 million years old, dating back to times before the continents split apart. Although proteas are usually found in warm, dry regions of Africa, South America, Australia and New Zealand, they are now grown in Zones 8 – 11 of the Northern Hemisphere by gardeners who like a gorgeous and unique but challenging plant.

This pincushion protea, Leucospermum cordifolium, looks lovely nestled in some succulents.

The name “protea” comes from the Greek myth of Proteus, the shape-shifting son of Poseidon to reflect the many shapes and sizes of the flower and plant. All proteas have adapted to survive in poor phosphorus-deficient soils by growing clusters of “proteoid” roots with many short, feathery branches that also help the plant absorb water from infrequent rain or coastal fog. As a result, proteas don’t like being over-watered or exposed to phosphates in the soil.
Propagation is most commonly done from cuttings or graftings in the fall but can also be done from seed in the spring. Seeds can be started in bags filled with quick-draining mixtures of 5.5 pH soil and Perlite. Scarification from sandpaper or hot water may also be needed: dormant protea buds and seed pods probably survived Australia’s devastating wildfires this year as they have adapted to using smoke and heat to overcome dormancy. Suppliers in California, Hawaii and North Carolina can provide starter plants.
Proteas, also called sugarbushes, are very rich in nectar that attracts all types of winged creatures to accomplish pollination. Flowers emit a yeasty scent and remain closed until triggered by the feet of a mammal, bird or insect visitor when they snap open to reveal their pollen. In commercial settings, flowers are bagged to enclose pollen and manually tapped to encourage them to unfurl.
Growing these beauties in the Southside humidity is possible but takes some extra work as it always does when working with unusual non-native species. The biggest considerations are providing enough drainage in acidic soil, good air circulation, strong light exposure and protection from excessive ambient moisture to mimic the protea’s arid, wind-swept ancestry.
In our area, this likely means confining the plants to a frost-free greenhouse. Pincushion protea varieties do best in indoor care. Some general considerations for growing proteas include:
1. Good growing medium: Because most proteas are not frost-hardy, it is recommended that they be planted in large greenhouse pots containing a very loose mixture of 50% peat and 50% coarse sand or Perlite. This allows for a low pH acidic base that drains readily but also retains a bit of moisture around the roots. No bone meal or fertilizer is added but the surface can be covered in a mulch of wood chips or decomposed pine needles.
2. Care of the root system: Protea roots should not be cut or pulled apart. The intact root ball should be inserted into a well that is twice as wide and twice as deep as the ball. Carefully shake more potting medium into the hole around the root ball. Fine roots will grow mostly horizontally near the surface and should not be cultivated as the plant matures.
3. Full sun: Bright sunlight for 6 – 8 hours is necessary to encourage blooming, usually in the second year. Proteas will tolerate warm temperatures but also flourish in cooler areas.
4. Air movement: Proteas should not be crowded. Separate pots by several feet to allow good circulation. Adding a fan to the greenhouse can help reduce humidity levels and keep the internal temperature well under 100°.
5. Cautious watering: An initial soaking application of water can be done after container planting. Always water at soil level; the foliage should remain dry. Water new plants before the soil surface completely dries out. Established plants need water only every couple of weeks. Never let plants sit in water in drainage dishes.
6. Spare the fertilizer: Protea roots don’t expect to have an easy time finding nutrients – in fact chemical fertilizers or manure will burn the sensitive shoots. An organic fish or seaweed emulsion can be used to provide nitrogen once or twice a year.
7. Yearly pruning: Proteas prefer to spread naturally but can be pruned right after flowering. Remove the flower heads and cut long branches back to above four or five leaves. Plants in large pots may need to be staked to add extra support.

Look for fresh proteas in commercial cut flower arrangements, especially bridal bouquets - they are long-lasting show-stoppers. The dried flowers also can be enjoyed for many months.
While we are all still practicing ‘social distancing’ due to COVID-19, and all county buildings are closed to the public, if you have questions on ground cherries or other vegetables, you can best reach an Extension Master Gardener or Extension staff member by sending an email to wmccaleb@vt.edu or you can use ask@ssmga.org. Stay safe and wash your hands.