We live at 7000 feet and have a volunteer shrub that is over 6 feet tall. The flowers are about 1/4"-3/8"; cream/white colored; with 5 wee petals and a pale yellow, spikey center. Also, the flowers are clumped in cones of about 8 rows.
The flowers are lightly scented, very pleasing to the nose. The bees love it.
I thought it might be some kind of a lilac or butterfly bush or butterfly weed?