The Callistemon which I had seen in Aberdeen in the past was clearly a one off fluke, I would not recommend it as a hardy plant for the North East. However I will give it one more try as a container grown plant which I will over Winter in the unheated greenhouse.
The Callistemon which I planted in the Spring of 2009 ended up looking very sorry for itself by February 2010, the leaves were dry and crumpled up, I reckon the temperature just got too low at times for this plant, it was an exceptionally hard Winter. This is the third attempt with Callistemon, I was convinced that we had on this occasion found a position that was so sheltered success would be more likely.
I have seen a mature specimen growing in Aberdeen admittedly only on the one occasion but we are in a bit of a frost pocket, so perhaps if you have a go yourself you may have more success than we have.
Callistemon (Bottlebrush Plant) comes from Australia a genus of 25 species of evergreen shrubs and trees. They have simple lance shaped leathery mid green leaves but the shrub is mainly grown for their bottlebrush like flowers.
This plant is mostly seen with colourful red flowers some of the other less common ones have flowers of purple, white or pink.
The hardiest and the one that you should have a go with is Callistemon Subulatis. Red flowers in June/July lemon scented and grows to a height of 150cm. Plant in a sheltered sunny spot in moist moderately fertile soil which should be neutral to acid. Keep the plant tidy by pruning after flowering period is over. Watch out for red spider mite.
Only reason I have for listing this plant is because it never fails to turn up in our garden centres each year.