How to grow Proteas

New grafts should be placed in a lightly shaded mist bed and ensure that large water droplets do not accumulate on the leaves of the silver mimeteses – use the finest foggers at the correct timing in relation to the evaporation. There is usually a minimum of a month before shoots may start after which they can be progressively hardened off. A weekly spray of seaweed extract with fulvic acid is a great help, and the bindings should not be removed to check on callus formation. Deep shade will cause the grafted entity to be deprived of photosynthesis and will be particularly detrimental to both scion and stock.
I tried spraying a weak IBA mix on about 20 grafted plants and broke open the grafts to check on callus formation, a few every seven days, but there was not much difference compared to the control at the end.
A great threat to the new graft is adventitious shoots that start below the graft union on the stock and even on the stock at the meeting of the stock and scion. These intercept nutrients needed for callus formation, and even when the size of a match head can set back or even abort the scion. Regular checks and removal of these is vital.
Too much aftercare can also be harmful if the grafted plant is starting new shoots, especially with the silver mimeteses. As a well- established rootstock is in most cases like a booster rocket, and if the plant is in a protected shady area for too long, etiolation on new shoots can quickly occur and the plant will need shifting to a sunnier position.
The original leaves of the scion will deteriorate and die back from the tip as the new shoot’s demand for nutrients increases. It is possible that the scion’s new shoots are demanding first from its own resources, indicating that there may not yet be enough harmony between stock and scion and etiolation forces that stress. The scion’s original leaves will then start to deteriorate first and then the new etiolated leaves on the extending shoot. This is easily seen with the silver mimeteses but not so with dark green protea leaves although it might be happening. Nipping out the rapidly growing tip should be considered to slow down the rapid growth while the graft union is still in the consolidating stage. Rather move the plants earlier when the first scion buds appear and as not all scions bud at the same time, inspections for this should be regular.
The silver mimeteses can grow rapidly after grafting especially if they have been fertilised, so much so that it can be advisable to slow the growth by pruning. The effusive growth becomes lax and the plant flops on the ground, ruining the shape of the shrub which is difficult to rectify. Unfortunately, because they are so beautiful, the owner is reluctant to see the first inflorescences pruned off just as they start! Laxity also leads to etiolation if they are planted out into shade or semi shade, they grow better in full sun and not in close proximity to other plants. After they are established, perhaps in their third year, other plants can be grown within the drip line e.g. tall ericas.