Answer: What you're growing is probably Abutilon pictum, but I'm not able to find a yellowing flowering cultivar with variegated leaves. Yours is truly special! You may be able to start a new tree by taking a cutting from your plant (they generally root easily). Take a 4-6" stem cutting in June or July, strip the lower leaves, dip the cut end in rooting hormone, then set it in moist potting soil. Use plastic wrap as a loose tent (to help conserve moisture) and set it in a shady spot in the garden. It should root in about a month.
Best wishes with your flowering maple!
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