We often enjoy the beauty of magnolias inside by picking them when they are first opening,with at least one or two tepals unfurled. At this stage the top of the stigmatic column in the centre of the flower should still have a glistening look about it which means it is just opening and still female receptive. They should be put into water as soon as they have been cut, and if in not too hot a place, will last a week or more in water, depending on variety. Magnolias are generally trouble free garden plants. The commonest problem is bacterial leaf spot which appears on the new growth in the earlier part of the season while conditions are warm and moist.
Some varieties are much more prone to it than others.
This is best controlled by a copper spray in winter, followed by copper sprays 2 - 3 weeks apart at summer strength while the plants are putting on their spring growth. If you grow potatoes or tomatoes and spray to prevent blight, just mix up a little more spray and do your magnolias if this is a problem for you. Another problem is borer . A problem which occurs sometimes is a blackening and death of the stems associated with a strange fermenting smell when examined closely. Sometimes half of the tree may be infected, but very rarely is it completely fatal.