Why prune Proteas
There are a few reasons why you would want to prune your protea bushes:
- To lengthen its productive lifespan by cutting it back from time to time
- To adjust the shape of the bush to provide more or better flower-yielding branches
- To remove diseased branches before the infection spreads to other parts of the plant or other bushes
- To improve the plant's genetics by encouraging shoots from branches that produce long-stemmed flowers, and cutting off shoots that produce short stems
When to prune Proteas
There is no simple answer to this question. You can prune at any time that suits you. The best times, however, are:
- Just before the plant undergoes its growth spurt (but you don't always know when that is!)
- As part of cutting the flowers (this is particularly effective, because you can base your pruning strategy on the flowers, stem lengths and other factors that are only visible during flowering.
- During the early stages of budding, when you might want to reduce the number of buds by removing those that look weak or have short stems
- Any time you become aware of a disease or growth trend you don't want to continue
When NOT to prune Proteas
If you remember that pruning is like drastic surgery, you will remember not to cut your bushes when there is a lot of fungus about. The plant is vulnerable to fungus when conditions are warm and moist. When such conditions prevail, rather spray fungicide. (Fungicide is not harmful to higher life-forms like insects or other creatures).
How to prune Proteas - the basics
There are two cuts that you make when pruning:
- The growing cut that encourages growth through the buds on the tip of the branch (as shown marked (a) on the diagram above) where strong and straight heading stems are pruned to encourage growth, and
- The pruning cut that lops off a branch and stops all further growth (just cut the branch flush with the branch it grows out of - as shown in (b) above where weak, crooked or downward pointing stems are cut off.
In the diagram on the left, the middle picture shows a cut that will leave part of the stem without any flow of sap (since it will flow through the bud). The stem above the bud dies and becomes a source of infection and disease to the plant. Don't do it. On proteas, the buds are just above the leaf-stems (unlike the picture above where only buds are shown).
How to prune Proteas during flowering
While pruning during flowering, you need only ask yourself this question as you cut the flowers:
Do I want more flowers like this next year?
If the answer to this question is yes, then cut the flower so that you do a growing cut just above a bud. You are leaving a part of the flower's stem as a base for further flowers like the one you are cutting. ((a) in the top diagram)
If the answer to this question is no, then do a pruning cut - cut the flower stem off flush with the branch that it is growing out from. ((b) in the top diagram)
Where to prune Proteas during the first three years
It is important to prune your young proteas after planting, to avoid having long straggly stems and an ugly plant that does not produce many flowers.
A few months after planting, or as soon as the young plant has a shoot or main stem longer than 30cm it should be tip pruned. Do this by pinching out the growing bud or by cutting off about 3cm.
A year later, do the same tip pruning as with the young plant, but also thin any weak or spindly growth - leaving three or four main stems.
After two years you can allow the protea to flower. After flowering, cut the stems back to 10cm from the main branch. Side growth, spindly branches or branches growing towards the ground should be pruned off flush with the stem.
How to prune Protea Cynaroides
Some protea species have a large swelling of the trunk/root just under or at the soil surface called a lignotuber. This acts as an underground trunk and is an adaptation to surviving fire or severe damage. The lignotuber has dormant buds that shoot after fire or drastic pruning of the plant.
You can prune protea cynaroides to form a shrub, or you can go with straight stems from the lignotuber the way commercial growers do.
How to Prune to form a Protea shrub
Pruning to create a shrub-like habit as shown above is quite difficult and can result in a spreading and messy plant.
Commercial pruning of Protea cynaroides
The best way to induce a reluctant Protea cynaroides to flower, is to cut all the stems back to 5-7cm above the ground. The new shoots will usually produce flowers. Commercial growers prune to ground level leaving 5 - 7 cm of stem. New shoots will appear from the lignotuber and in 12-18 months will produce a flower bud.
My strategy when Pruning Proteas
I find it useful to imagine the protea branches as pipes giving growing energy to the buds and new branches. By pruning weak branches you are preventing the protea bush from wasting energy and redirecting that energy to other parts of the bush.
This picture of a Leucospermum reflexum branch tip shows how the energy that was flowing into the tip is diverted to all the buds near the tip when you cut the tip off.
Disclaimer
Fijnbosch Farme provides this information in good faith and cannot be held liable for success or failure of your protea-growing efforts.