We teased my grandmother relentlessly about that tree. One of the Lithuanians gave her the tiny sapling, and she nurtured it for nearly fifteen years, hoping for a first bloom. Her faith never waivered. True story.

***

Touch Mimosa Pudica and she will recoil, closing her fine green leaves, playing dead to deter predators. She’s one of a few plants with a functional nervous system.

***

An easterly breeze puts Harpo’s olfactory system to work. He leans into the familiar aroma, and leads me between the boxwoods, then through a flower bed where he tramples the newly-planted impatiens.

“Be careful!” I scold him.

We stand beneath Mimosa Pudica’s twenty-foot canopy, and I see that her fluffy pink plumes have made their annual debut. Just as lily of the valley signals my birthday and lilac my mother’s, Mimosa Pudica signals Harpo’s.

***

My grandmother suffered a massive stroke before Mimosa Pudica rewarded her with a single flower. It happened on July 12, the Feast of St. Veronica, her patron saint. She died a few days later. Her tree bloomed two years later, on July 12, the day the dog was born, before we even knew he existed.

***

Botanists say that Mimosa Pudica is capable of learning. She can remember how to react to stimuli, and be trained to accept human touch without recoiling through Pavlovian conditioning using light as a reward. I wondered if my grandmother gently trained Mimosa Pudica to accept her touch, the way she coaxed me when she took me in, wounds and all. Remember the patience it took for Harpo to come around to affection after we rescued him?  

Mimosa Pudica’s neighbor Big Jerome the Picea Pungens has no use for a functional nervous system. Get too close and his sharp, deciduous needles will tear your skin. He even might toss a pine cone or two at your head.

Fight or flight, these two.

And then you have Acer Palmatum, the Japanese Maple in the corner over there, vulnerable because they lack any defense mechanisms to deter contact from undesirables. All three trees survived, even after my grandmother stopped caring for them.

***

I pluck one of Mimosa Pudica’s brilliant pompoms.

“Happy fifteenth,” I say as I offer it to Harpo for a sniff. He tries to eat the blossom, but quickly spits it out. Typical. I extend my hand, and he accepts a neck rub without recoiling, no questions asked. I think my grandmother would have liked him. The tree’s delicate branches sway above him in the breeze, back and forth, while Big Jerome stands motionless behind us, ready to draw blood.