Olga's in bloom

This is not Olga, this is the arabis in the pot by the front door. A wonderful springtime display. And as you walk around the arabis toward the back yard, you notice that I've not yet trimmed the dead flower heads from the hydrangea. Here's why:

A pair of golden-capped (or crowned) kinglets are trying to raise a family. I wish them all the best, and am happy to look at the dead flower heads for a while longer.

Here's a particularly pretty tulip in the back border back by the elderberry tree:

And here's a bit (over to the right) of Olga (rhododendron Olga Mezitt), which Mum planted for me in March:

She's got lovely dark, aromatic leaves, and is blooming up a storm. I'm curious, though, about the stalks of white flower next to her - they look like a really stretched out lilly-of-the-valley. Anyone know what they are?