Bendigo Ridge is also a small-scale flower farm, growing proteaceae: Proteas (Sugarbushes), Leucadendrons (conebushes) and Leucospermums (Pincushions). The proteaceae family also includes the genera Waratahs, Banksias, Grevilleas, Macadamias and NZ-native Rewarewa. Initially it was to be a revenue stream, but nowadays if more of a hobby that maybe one day we’ll be able to recoup some costs from.
Most of our plants come from garden centres ultimately sourced from “Garden Jewels” in Kapiti. We have also grown some plants from cuttings (mostly leucospermums). We have about 75 plants in the ground across four different planting areas. Ones planted later have greatly outpaced the earlier plantings now that we know what we know.
Here are some learnings – it’s not entirely scientific and based on our experience so your mileage may vary.
1. They are happier in the ground than in the pot
In the nursery or garden centre, plants are packed together and kept a bit shaded and cool, with frequent watering. We seldom replicate that when we get them home, and they dry out and overheat. They can’t form proteoid root systems and are at risk of getting root bound. Get them in the ground as soon as you reasonably can. We held some plants in pots for over a year because we were delayed in getting land with water. Mostly they survived, but weren’t at all happy.
2. Preparation of the hole is vital
Our early failures were thinking that the soil was good, and merely digging a big-enough hole would suffice. We were wrong, given that our soil is denuded and too fine with a rocky underlay. When we started digging compost in (and combining with the soil we dug out) they started to grow much better. Bigger (for the hole) is generally better and you may need to stake the plants. If you are going to, then always stake at planting time to avoid damaging those proteoid roots.
If you don’t have good drainage, plant in a mound rather than flush with the surround ground.
3. They do like water!
Yes, the myth goes that they like poor soils and are drought tolerant. There is truth in that, but survival isn’t the same as flourishing. If you have well-drained sandy soil (eg coastal) then you can water almost as much as you like. Some say smaller amounts daily. If (like us) you have claggy soils, then one deep watering per week is good. An adult shrub needs something like 35l per week! They will survive on much less, but if you want vigourous growth and long stems then they need water.
The ideal rainfall for a protea with no irrigation is around 850-950mm per annum. Anything less and they are just surviving, much more (>3m/a!) and they might equally be unhappy.
Remember the advice that they don’t want to sit in water (ie poorly drained soil) is not the same as they don’t like water. They love water!
4. They do like nutrients!
As long as what you put on is low in Phosphorus (P). Don’t use general purpose fertilizers. I have been using Tui Seaweed & Fish liquid which is fairly economical and has given the plants a tremendous boost. Low dosages are good, don’t overdo it. And generally only fertilise in the growing season.
As with water, thriving is not the same as surviving. Just be careful of over doing it and phosphorus. They still need phosphorous and potassium, but look for a NPK ratio something like 10:1:5.
Another trap for the unwary is what the soil had in it before, and what are you doing around it. If it was previously fertilized then you may have a P or K problem. If so, get your soil tested and ask someone who actually knows about this stuff. And be careful of fertilizing other plants where that potent NPK mix could find its way to your proteaceae.
5. Much more mulch
Mulching is probably the most important thing you can do. A pinebark- or pineneedle- rich mulch is possibly best (it acidifies the soil) but anything is way better than nothing. Mulch keeps the ground cool and promotes a healthy soil biome which will help to fight fungal diseases. It keeps moisture in the soil and allows those all-important proteoid roots to grow. The proteoid roots absorb Phosphorus and moisture amongst other things. Because they grow in this mulch layer, avoid disturbing it too much, and definitely avoid herbicides if you can.
6. Prune and protect when young
Experienced growers will tell you not to let your plants flower when they are young. Of course we all want to see some flowers, but it’s not ideal for their development later. With leucadendrons, encourage branching lower down by cutting or pinching lower shoots. More low shoots = more long stems. Similarly for proteas and leucospermums, a compact start is a good start.
Most of ours struggled early on and are a bit rangy lower down. With most proteas, they won’t shoot from bare wood (p.cynaroides and sometimes l.safari sunset being exceptions) so you can only prune down to the last 7-10 healthy leaves.
When young, they also need more frequent watering, protection from the sun and frosts. When they are 1-2 years in the ground, they should be hardy enough to hack it on their own.
7. Nip out bypass shoots early
Actively growing protea plants tend to throw shots from just below the flower buds. This is really not what you want, because it competes with the flower and tends to result in a taller bush over time if you leave them. If your plant has been struggling and that’s all you get with short flower stems, you’re probably best to pluck the flower bud and let branching occur (you don’t want to for sure, but it’s best for the longer term)
8. pH isn’t that important
They prefer an acidic soil (< ph6.5) but it isn’t vital. You could occasionally put on some sulphur-based products eg aluminium sulphate but it only affects their ability to efficiently take up nutrients. It won’t likely kill them if they get enough nutrient in the right form.
9. Frost can be very detrimental
Most varieties flower in winter or spring, and have a strong growth flush in autumn. Early autumn frosts will snuff out this soft fresh growth, and winter cold will damage buds. Not sure what you could do about it to be honest, but a healthy plant will cope better than a stressed plant. Some varieties cope better than others. This includes pink/red ice, p.grandiceps, l.safari sunset. Most leucospermums (pincushions) are fairly tender when young.
Other References
https://www.proteaatlas.org.za/growcrit.htm
Books
- Handbook of South African Proteas Cultivation: Juan Alberto Rodríguez Pérez. This is a very scientific book with lots of great information if you are planting a farm, but could make your head spin if you aren’t a horticulturist.
- South African Proteaceae In New Zealand: Lewis Matthews. A nice reference will good information about specific species and varietals available. Published in 1983 and showing its age.
- Protea A Guide to Cultivated Species and Varieties: Lewis Matthews. Published in 2016, this is a useful and more modern guide to planning a protea garden. It highlights Lewis Matthews photography passion.
- South Africa’s Proteaceae: Know Them and Grow Them: Marie Vogts. The “OG” of protea books that is remarkable in its depth and breadth. It really applies to the Western Cape so not as relevant to NZ conditions and varietals. If you can tell me where our copy is I’d be grateful 😂