You have cited one point of contention much less an issue here in merika, that of shading out your neighbor, or your only little patch of sun. I'm not even sure that ecologically-speaking, I see Pawlonia as the unmitigated disaster on your shores as it apparently can be in certain parts of the SE US. Goes right back to our other discussion....what was or would be growing where you are? Heath? Well then, protect that unique community. But if just your run of the mill area of non-native grasses and weeds, I say let the Pawlonia grow! Of course, I might be missing something, not being resident there!

+om

AFAIK, wisconsintom, Pulownia does not self sow here so it is not invasive, so far. It's just its fast growth and potential size which make it unsuitable for our small gardens. Personally I like it, especially in flower. In a large park or garden it looks fine to me.

Yes, perhaps it's just down to where and how it gets used. Is it that you guys don't accumulate enough heat for it to mature it's flowers/fruits/seeds? If so, that's perfect natural control mechanism. In any case, I get what you're saying, having been educated on the English garden situation in these very pages, insofar as the need to not block each other's sun, etc.

But yes, in parks and so on, could be a perfectly reasonable plant to work with. I'm just as much a sucker for bright color as the next gardener. So, do the pollarded ones produce flowers then?

+oM

I was going to say this was another example of certain trees being recommended by folks in other regions, getting into the popular consciousness, and ending up planted in areas it isn't really appropriate. However, it gained the Royal Horticultural Society's Award of Garden Merit. What were they thinking?
Personally, I *HATE* the tropicalismo look. I do like trees that flower, though.

I bring it back to Ancient Lights and the <i>Leylandii</i> laws. In a few years neighbors will notice and these trees will come down.

Seedlings appear in regularly watered flower beds and among rocks here so I don't see why these would not occur in Britain also. The thing that would limit the tree to such locations in my area would be the annual significant summer drought, something that is not present in Britain.

Many other horticultural favorites that have gone wild to a nuisance extent in eastern North America have never done so here, due presumably to this same summer drought. For instance the one time I saw a wild living Japanese honeysuckle here it was in a little pocket at the bottom of a slope, just above water level along Lake Washington. There would have been some moisture coming out of the slope as well as from the lake, without - it would seem, unless this species has some tolerance of flooding - the plant ever being in an actual puddle.

(It was also a warm, sheltered aspect, which probably didn't hurt either).

No, the pollarded ones don't bloom. They are grown purely for the dinner plate foliage.

Unpollarded ones do flower and set seed, at least here in the SW, but I've never seen or heard of seedlings being a problem. Possibly the seed doesn't ripen sufficiently?

Embo - what summer temperatures do you get? From what I can find the seed needs ca. 3 weeks no lower than 70f. This is very unlikely in the UK, even at the height of Summer. It is also possible that seed never properly ripens due to lack of warmth in late summer. Whatever the reason I don't recall ever seeing seedlings. Have you, Campanula?

Paulownia in the UK

That seems pointless. If you don't get a majestic tree shape and you don't get flowers, I don't see why you'd want to go to the trouble. But then, I'm not a fan of tropical looking foliage.

The council have also been planting them - I was astounded to see that they are much more precocious than I had thought, flowering while still very young (must have been thinking of liriodendron). Kind of freaky, seeing these full-on, very untree-like blooms (in austere chalky Cambridge - not a rhodie or Camellia in sight). Nonetheless, they really seem to have appeared out of nowhere (I am sure I would have noticed, tree novice that I am)

The ones planted on the common or our open green spaces, I also like. My neighbour's, now less than 2.5 metres away - probably less so.

edlincoln, those who grow them for the foliage only probably don't even consider them as trees. They are treated like perennials. It isn't really fair to say they don't produce a majestic tree shape if that isn't the point. Plenty are grown as trees, uncoppiced. (I've just realised I've been writing pollard when I meant coppice.)

While catalpas are also coppiced hard to get those huge leaves, they have been around on the full size tree scene for a long time - there is a large one just at the back of my house which was planted in 1962...but unstooled pawlonias are a much more recent addition. Since the large ones have appeared on municipal land, any seedlings would meet with a rapid end from the council mowers...and my neighbour's 3-4 year old (shudder) has not yet flowered.

I think our council went into panic mode since so many of our chestnuts and ash are under threat...and started looking for fast-growing replacements.

Hee, while never going to be "trees" here, hardy banana species have began to be the rage in my neighborhood. Both my neighbors have them..and I see lots along the streets too. I assume this is musa basjoo. At least we won't have to worry about them being invasive, though the clumps seem to multiply well.

Catalpas (as trees) are a mainstay here. C. speciosa is the native one...but I'm sure we have bignoides planted around too. They worry me much less than privet, japanese honey suckle, and our native maples (such a reseeding pest, esp acer saccharinum) as a yard owner/maintainer. Of course our yards tend to be MUCH bigger than your English stds.

Paulownias aren't huge trees, so I don't get the fear of them engulfing British yards (at least, any more than a zillion other sorts of trees).

The claim that seeding won't occur unless there are at least three consecutive weeks where temps are always above 70F sounds bogus to me (seeing that places like Philadelphia have had Paulownias energetically seeding themselves around, and even in the height of summer there will be nights where the temps there drop below 70).

For whatever reason, Brits apparently can grow some plants with impunity that are invasive here. I still remember reading with horror an article in an RHS journal praising pokeweed as a wonderful ornamental for the perennial garden. Maybe Paulownia tomentosa is one of those species.*

*or perhaps it will break out of confinement unexpectedly to become the next giant hogweed.

Poke weed in a mixed border.

(BTW since it is a US native it can't be invasive. A nuisance in gardens, possibly, but not invasive.) And although Giant Hogweed is a bit of a nuisance if you actually touch it, it is relatively unusual to find it in the countryside. It certainly hasn't ousted native flora in the way Knotweed or Himalayan Balsam have.

True, Rusty - any forest tree in a tiny British garden is a menace (and given the million options for small mannerly 4 season trees such as sorbus, mespilus etc, why would anyone plant a maple in 5metres of space...but still, they do - robinias and gleditsias were the last craze...sometime after the bamboo fad))...but the sheer speed of this pawlonia engulfment has me very bemused indeed - had it been planted along my border, I might have been very tempted indeed to have a nasty accident with a flailing knapsack lance and some strong liquid death.

I admit to an unreasonable love of all the apiaceae family - so much so that I invested in seeds of giant hogweeds from Sakhalin Island to grow in sneaky isolation in one of the clearings. I have kept very quiet about this and will, like all responsible types, whip the seed heads off before allowing them free reign.

That's not the typical weedy poke weed of the eastern US. (though it could be another, prettier species)

"For whatever reason, Brits apparently can grow some plants with impunity that are invasive here."

Likewise, I wish we could grow their weeds with impunity - often we cannot. I bet Himalayan Balsam would die from too much summer heat here.

My guess is Paulownia has a double strike in the UK: summer not hot enough to always fully ripen the seeds, and summers not warm enough to harden off the seedlings for winter. The slightly sunnier summers of the Seattle area (100 hours more July sunshine than London) would be enough to allow them to seed a bit in watered areas, as bboy notes.

As I've said before it's really a shame someone doesn't create a sterile version...triploid maybe, it could perhaps have even bigger flowers. They are pretty in bloom...as close to a Jacaranda as we will ever get in a cold winter climate. NALT IIRC mentions that Umass Amherst tried to, but the project was a failure.

Hah Jacaranda! Now there's a flowering tree. Maybe pair that up with a couple Delonix regia-there should be many years in which they'd be blooming together-and I think you'd have quite a show. Oh hell, a copse (not a coppiced copse) of the Jacarandas-I think they're going to usually be a little taller than the flame trees-then surround that with the full range from red through orange to yellow of the Delonix. As for Paulownia, I think you're on to something David-could really be a useful item if the sterility could be achieved. Permaculture people often mention them too for their fodder and soil-enriching utility along with other uses. It would seem too that wild areas that are or will be developing into the next successional stage should see a remedy for all the invaders as it gets shaded out by taller-growing species. Then again, I could describe common buckthorn in exactly the same way, in terms of ultimate height compared to most forest species, etc. but that's still growing everywhere anyway. And of course, if continual disturbance is what's happening there, where the Paulownias are growing, it'll never develop anyway.

+oM

ps...had the wrong tree coupled with the Delonix regia. fixed that just now.

Paulownias aren't huge trees, so I don't get the fear of them engulfing British yards

A 'Lilacina' in Seattle was 79' high in around 2005. The largest record for P. tomentosa is 105' x 21 3/4' - that's a trunk approximately 7' thick.

The pokeweed in the photo might be Phytolacca acinosa (?)