Magnolia Campbellii is indeed not a native of this island but comes from the forests of the Himalayas, from Assam, Sikkim, Bhutan and to eastern Nepal where it tends to live 2400-3000m above sea level. The white form was first found in 1838 by a assistant surgeon of the East India company William Griffith but he was beaten into putting his new find into print by the very famous plant hunter sir Joseph Hooker. He found the pink form in 1855 and named it after the political resident based in Darjeeling, Archibald Campbell
The trees can be fast growing in its younger age, sometimes putting on as much as 4ft in one year, it will take many years to get to its full height of over 100ft in the uk. The leaves themselves again are rather massive measuring up to 10inches long by 4inches wide. The humongous flowers can be as much as 20inches wide! The scent is truly delightful, rather delicate but never less very beautiful. If the tree is grown from seed, it can take up to 15 years for the white form to flower and up to 30 years to flower for the pink forms. This time can be reduced if the plant is grafted onto a root stock, normally magnolia campbellii subsp mollicomata, normally down to about 10yrs. The only problem with this queen of the plant world, is that it does flower quite early here in the uk and does tend to get frosted by some late winter frosts.
Magnolia wood is also greatly valued as a light but very strong wood.
Growing wise it needs a good damp very fertile soil that’s slightly on the acidic side. Certainly for the first few years feeding with something like Vitax Q4 fertiliser and well rotten leaf mould or compost would be ideal. Planting wise it’s well worth trying to get a small tree as this will establish much more quickly, planting hole should have a good amount of organic matter added, Vitax Q4 and also mycorrhizal to help to get the plant established. It needs very little pruning at all, just a little formative pruning to remove crossing branches and lower branches. As for pest and diseases, the normal one like honey fungus, phytophthora, slugs, rabbits and deer are the biggest problem here in the uk and again more effected in a early age. More importantly this plant needs space and the the best thing to give it.
There are many forms available to buy but these are the more common forms to buy and plant ‘Alba’ is the white form that is rarely seen, subsp mollicomata is a more pale colour pink
The places to see these magificent trees are the normal places like Sir Harold Hillier Gardens, Wisley Gardens, Kew, Marwood gardens and so many of the beautiful gardens in Cornwall is where it really shines, places like Caerhays, Lost Gardens of Heligan, Trebah, Trengwaiton, i could go there are so many places to enjoy them. to buy Burncose nursery http://www.burncose.co.uk is a great place to try