About the year 1808 a Mr Thompson, then a nurseryman at Mile End, noticed a distinct plant amongst some of his seedlings of Magnolia virginiana. He propagated it and ultimately distributed it under the above name. It is now usually regarded as a hybrid between virginiana and tripetala, although there is much less evidence of tripetala than of virginiana. It is a shrub of loose, ungainly habit, producing very vigorous unbranched growths of great length in one season. The leaves are 4 to 10 in. long, very glaucous beneath, and otherwise similar to those of M. virginiana. The flowers are creamy white, fragrant, much larger and less globular than those of M. virginiana, the petals being from 2 to 31⁄2 in. long. They are borne mainly in June and July. I have not seen or heard of its producing seeds, but if it did and these were sown, the question of its hybrid or other origin would probably be settled. Bot. Mag., t. 2164.
M. × thompsoniana received an Award of Merit when shown by Graham Thomas on 17 June 1958. It is a coarser plant than M. virginiana, but faster growing, and flowering when young.