As long as the original cutting had a node under the soil line, it should put out short stolons that will eventually form a clump. The one I saw at the Huntington Botanical Garden in the 80s was so big that parking a small pickup truck over the cut back bed would not totally cover it.

You can control its size, of course. If you are not sure if there is a subterranean node, plant it deeper and add some mulch (hardwood bark is best.)

Bloom time is controlled by average daytime temperatures. The length of the period of coolish autumn days is the determining factor. The longer this period is, the sooner autumn and winter blooming sages will flower out. The worst condition is to have a long, hot summer and go to winter conditions over less than 14 days.