Haha. Thanks Cindi! How fast you ID's it.;) You mean you just place the rock so the stem is on dirt, and it newly roots in place?

Spiraea crenata perhaps.

I'll try to get a better close up since the one above is slightly blurry. I see there are many species of Spirea also (like Viburnum). It's more like a privacy hedge now, about ten foot long and three foot deep in front of a small brick patio.

It's quite possibly bridal wreath spirea, Spiraea vanhouttei, which has that arching form and white flowers in that bloom at this time of year.

Yes, S vanhouttei is a very good candidate. Unfortunately the picture of the leaves is out of focus so we can't determine the shape of the margins very well.

Thank you for your help. Here is a close up photo of leaves:

Looks 'Bridalwreath'-ish to me! One of the oldies-but-goodies kind of plants.

The name Bridal Wreath is used for several different Spiraeas. S vanhouttei matches those leaves I'd say.

Thank u all. Catkin, just a lovely photo. floral_uk, yes, Spiraeas. Long time since latin. Thanks Cindi_KS and NHBabs; you know your flowers. Always look forward to this spring bloom.