So there I was earlier this week, on the way to see a client in Wellesley, MA, and I passed this huge colorful streetside show:

Trees with colorful flowers? Think about it: How many of them bloom early in the Spring? All those pink cherries. Those pink or yellow magnolias. Rosy-pink "redbuds"? Those lavender paulownias?


And then, the dogwoods come out, and so all the trees thereafter have white flowers only? Stewartia, catalpa, fringe tree, franklinia. Think about it: A tree that blooms later than May and doesn't have white flowers?


Only two, I think: Mimosa (pink blossoms, ugh) and the other one here on that Wellesley streetscape: Goldenrain tree.  Ugh, what a sticky-sweet name, and way too similar to yet another early-Spring yellow-flowered tree (Golden-chain tree, laburnum) plus a climbing rose (Golden Showers).


Let's flip over into the Latin:Kohlreuteria paniculata. Thank you, Mr. Kohlreuter whoever you were. "Paniculata" means that it has big panicles of flowers. Does it ever:

I had never gotten this close to the flowers before—get a load of my grimy man-of-the-earth fingernail!—so I was surprised to see the orange-red flare at the base of the petals.  The pollen is orange-red too—nice coordination!—and the petals are folded back to expose it completely.


Kohlreuterias in my experience are fool-proof as long as they're planted up a slope, even a tiny one.  They lose their confidence if surface water doesn't drain right away.
Sun and heat are welcome, and the trees are drought-proof too.   So tough they can be used as street trees.


We'll take another look at kohreuterias later in the season: As if these unique flowers weren't enough, they mature to colorful inflated pods by August.


In the Fall we'll confirm if the tree gets good Fall foliage.  The branching and bark are very satisfying in the Winter too.  A four-season tree then?  Very possible, and very essential anywhere (Zone 5 - 9) it's hardy.

Wow, what foliage!
Not a chestnut, not a sassafras. It's a .... well, what IS it?
Firmiana simplex, a Chinese species very popular as a street-tree in Japan, and naturalized here the South. So it must be plenty calm even when there's heat, pollution, heavy soil, and the occasional lifted dog-leg. I've kept one in a pot for years for Summer display in Rhode Island. Here it was, a star of the shot in a Summer feature in Design New England. Click twice to see the photo full-size.

But here's a firmiana enjoying the cool life, right in the ground, in the East Village: Tompkins Square Park.
The green bark on young branches and even trunks is unique in sort-of-hardy trees.
The good news is that the tree is definitely and firmly Zone 7, which means NYC out to Long Island, plus the Cape and Islands and Southeastern Rhode Island. (Googling, I see it's also happy in the Missouri Botanic Garden. St. Louis is Zone 7? St. Louis is Zone 7! Who knew?)
I'll trial it in future Zone 7 projects. Hooray! But the downside of being Zone 7 is that Southwest Rhode Island isn't in it: The eastern tip of the North and South forks of Long Island keep the Gulf Stream at bay, alas. So my firmiana will stay in a pot, and hunker down, dormant and happy, in the basement all Winter. But a big potted firmiana—in Rhode Island, no less—is it's own statement. (And no, not because I let the tree grow bigger and bigger, with a huger and huger pot.) Why? Let's mozey back to those Japanese street scenes. (Oh I hope I have a picture from our Kyoto trip. I know this weekend!)
The trees are pruned back severely—you'd think that the entire city horticulture department had been taken over by the French.
And the trees were clearly handling the pruning well, too, in addition to all the other hard work of being alive in a hole in a sidewalk.
And so: being alive in a pot of Rhode Island dirt not that much smaller than the soil pocket for an entire street tree? Possible, very possible. And it's the pruning that makes it possible: As it limits the above-ground size of the tree, the below-ground part, the roots, are limited naturally.
It would be a thrill if the pruning also resulted in luxuriantly extra-large foliage, like it does when paulownia trees are pruned. To have these leaves twice and thrice as big as they are already?
That would be a performance indeed.

Plants with new foliage that's flushed purple are, I see, somewhat of a continuing theme for me. Yes there are the usual (but still lovely, still welcome) purple leaves of early-Spring peony clumps. And I've posted on Clematis recta 'Midnight Masquerade'. And I've "Maxed" on Catalpa x erubescens 'Purpurea' here. Wait until you see poliothrysis.
I'm returning to Chinese tulip tree today because of the rain yesterday. The matte finish of the leaves holds the rain, and even causes it to bead. And the dusty-to-dark shades of purple only highlight the light refracting in the beads. What a show!
The acid-lime-green bits at the base of each of the leaf-stems—there's a smoldering cluster of them at the center of the picture; click for the full excitement—are the leaf-bud scales that protected the nascent leaves through the winter. Even after each leaf is fully launched in the new season, the scale hangs on, adding it's electric note.
What a thrilling contrast with the purples of the newest foliage, as are the purple-fading-into greens of the older foliage ("older" being relative in that none of the leaves is more than a few weeks old: it's only May, and the tree didn't start leafing out until well into April). I have a trio of Chinese tulip trees, which I prune informally to maximize their interest in branching out and thereby creating more new purple-passioned foliage. (Plus, the pruning keeps the trees small enough that I can easily keep up the pruning. Even I'm not manic enough to attempt a twenty-foot specimen whose new tips needed to be pinched with a pole pruner.)
As long as everything is reachable from ground-level, or from a short step-ladder, when it comes to Chinese tulip trees, more is SO definitely more.

An enormous paulownia tree in full bloom is an astounding thing. Click on the photo twice to see it in all its huge full-size glory.
And to see the show in action, click the One-Minute Max here. The foot-high flower clusters point skyward, each with a score and more of two-inch lavender trumpets.
When the flowers fall to the ground, they keep their interest. This cardinal was scoping out the scene as long as I was, hopping back and forth, from the fallen flowers to nearby shrubs and then right back to the blossoms.
This bird is a florist of a sort. Who knew?