On my list of South African treasures, somewhere between the Springboks and Table Mountain, lies the crown jewel of the Cape Floral Kingdom – the Protea. Not only the national flower, a Protea bush makes a fantastic – and patriotic – addition to any South African garden. However, many Proteas need a little extra attention to detail or they may not be in your bed of blomme for long!
One of the first and arguably the most crucial elements to Protea planting is soil selection. I spent months wondering why my Albertinia pincushions weren’t growing in my KZN nutrient-rich garden. Well that was exactly it; many Proteas prefer poor nutrient soil and broadly prefer soils with a good mix of minerals. That’s how you start choosing your Proteas, you must first determine what mineral your soil predominantly comprises of: sand, lime, clay, or peat.
Starting with sand, ironically, deep sandy soils are typically the kiss of death for gardens, but Proteas love this acid-rich ground! Most Proteas will easily grow if you keep the phosphate levels in check as they are extremely efficient at absorbing phosphorous and nitrogen from the soil, and may take in too much. For soil that is rocky and contains sandstone, I recommend the Silky-haired Pincushion (Leucospermum vestitum), the Waboom Protea Tree (Protea Nitida), or the fail-safe Common Protea (Protea Caffra).
Limestone is a common element in South African soil – if you ever see the indication for “alkaline” on a seed sachet, consider that a green light. A more relaxed bunch, pH is not as critical for them, and get along well in gardens that contain acidic soils. You can even grow these Proteas on sand or clay soil, as long as it’s aerated properly with the proper addition of lime and/or calcium to balance towards alkaline, to be on the safe side. An easy win is the Limestone sugarbush (protea obtusifolia), as it grows in both acidic and alkaline soils. I can personally vouch for the Lance-leaf Sugarbush (Protea lanceolata), as it’s a hearty, lovely resident in the Koude Vlakte farm in Walker Bay, pictured in this photo.
For those looking for a sure-fire Protea bush, go for the clay! These Proteas are not as picky for their soil and are closer to a traditional garden plant rather than a rogue mountain bush. For a bit of insurance though, try to steer clear of chemical fertilisers and invest in a little bit of acidic mulch to seal the deal. If your clay soil is too heavy and quite dense, consider a raised garden bed (maybe 35 cm) or an underground drainage system. Some easy clay proteas are the green sugarbush (Protea coronate), the Common Suikerbos (Protea repens), or the more rare Kleinmond sugarbush (Protea angustata).
If you’re keen to make your neighbours green with envy though, I suggest delving into peat-loving Proteas. Traditionally found on the southern slopes of mountains, these Proteas grow in darker bogs with loads of peat, not boggy as in rich in moisture, but rather oxygenated (still water won’t do this), so keep an eye on drainage. Also, start your soil preparation now as you will need to build a bit of a laboratory in your garden shed; mix a variety of acidic organic matter into your soil before planting. Once you plant, hang up the “Do Not Disturb” sign; just keep the conditions acidic, this will improve drainage and prevent toxic levels of nitrates. I recommend the Black-bearded Protea (Protea lepidocarpodendron) for a Sugarbush variety or go for the prolific flowering Outeniqua pincushion (Leucospermum glabrum).
Overall, the main key to good soil for Proteas is having a well drained garden that has “hungry-rich” soil – be sure to monitor the pH range and keep it between 4.5 to 6.5, this makes it low in Phosphorous and potassium (common ingredients in fertilisers) and ensures low soil salinity. Additionally, for soil that is rocky and contains sandstone, I recommend the Silky-haired Pincushion (Leucospermum vestitum), and you can almost never go wrong with the laurel Protea (Protea laurifolia) – it’s a water-conscious/frost-hardy addition that does well in most soils even those with lime. Happy planting!
BY Shawn Graaff (www.premiergarden.co.za)