Answer: The Black Tulip Magnolia is a rapidly growing tree (usually about 24" of new growth per year). It should be full size in about 10 years, depending upon growing conditions and the care it receives. I think the planting site is a bit small for this tree so you may want to reconsider planting it in the site you describe. A better choice for such a small site is a large shrub such as a camellia or lilac, which you can prune and shape to keep it more in scale with such a small site. Best wishes with your landscape.
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