trumpet vine versus wisteria?

[Janet Macunovich 32]

Came straight to our email and we are posting it in hope someone out there will contribute a more optimistic answer!

 

I am wondering if I can plant a Flamenco trumpet vine over a wisteria vine? Wisteria never blooms, too hard to dig out. Flamenco supposed to do in part sun (5 hours) so what do you think? - G.B. -

 

Campsis radicans/Trumpet vine is so beautiful and the hummingbirds love the flowers... but we never plant it. We tend a few that others have planted. And we know of many that make us shudder even to consider the situation others have to deal with.

 

It's not just residential gardeners who find themselves in trouble once trumpet vine gets going, but public gardens gardeners. When we noticed all the suckers and inquired, the gardener at Cleveland Botanic Garden told us that the person in charge of the area around the big arbors covered with trumpet vine must go through all the beds under the arbors to about 20' out, removing suckers coming from the roots, and do this every two weeks without fail, or they will lose control of the whole area. Without that it will very quickly it will become one big trumpet vine thicket

 

These vines simply do not behave well anywhere. They sucker to beat the band, sometimes coming up clear around the far side of a building or at the other side of a driveway, the roots having followed the foundation or delved under the concrete for 50' or more.

 

Still, it would almost be worth all this trouble if trumpet vines bloomed reliably. Sadly, that's another strike against them. The new wood needs considerable heat in the first half of the year in order to ripen -- be prompted to develop flowers. Makes sense when you consider this vine is native to the toasty Southeast U.S. In many cases when it's planted in northern areas (northern U.S. gardens and also cool northern countries like England) the vine simply doesn't feel the requisite heat in the first half of the growing season. Grow it in part shade and its' even more likely to be cooler than its species requires. Result: Lots of leaf, no bloom.

 

So, ourselves, we wouldn't add a trumpet vine to any garden. Although if you do let one loose to climb a wisteria please tell us if we can come by some time and take pictures, and hear how it's going. Two such aggressive, diehard vines duking it out.... we'd be very interested in the outcome.

 

About the wisteria, not blooming:

 

Have you tried cutting the wisteria hard in March and July, and training top branches into HORIZONTAL position?

 

Wisteria is a species that blooms only after it's reached the top of whatever-it's-growing-on; after the branches at the top have flopped down of their own weight and grow each summer in unmitigated sun that stimulates flower bud formation. The key is to not let it keep trying to go up/higher, and strap some branches into horizontal position. Then don't let the new branches that inevitably try to go higher (it is a 70' vine, after all) remain above and shading the branches you've trained into horizontal position -- thus the July pruning to cut back all branches above the selected "top".

This process is illustrated in What's Coming Up #8.

 

We're posting this topic to our Forum in hope someone will comment here who has developed a more optimistic and productive handling of either vine. You can check it here for news..

 

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Thanks for asking about trumpet vine, by the way. Seems like we haven't posted many articles about this plant, and those so long ago we couldn't recall it without doing a Search over at GardenAtoZ.org.

 

What's Coming Up #110, on page 5, gives our how-to for controlling the suckers after trying to dig it out;

What's Coming Up #86 on pg. 11 describes how to prune it;

What's Coming Up #92 puts it in the huge-vine tree-killer category with wisteria and bittersweet,

and in What's Coming Up #200 we include it in our list of plants to avoid taking from others. (See , Bad Luck to Say Thanks, in that issue.)

We also gave the vine a hearty nod in What's Coming Up 54's department of 45mph gardening, an issue only just this day posted to Garden A to Z, thanks to your asking about it.

 

Here's trumpet vine in the spot where it's probably best grown - with pavement over most of its root system!

[Dsmith74 16]

Also, where is the wisteria growing? Because if it's on your house, that's another strike against growing trumpet vine on it. Wisteria is a twiner and goes where you put it for the most part, although it might crush a railing or something if it gets too big. Trumpet vine, on the other hand, is a gripper. It goes where it wants, and where it wants is into any little crack or hole. It will rip the siding off your house for fun. 

 

Oh, and in case the suckers aren't enough, sometimes the seeds are viable as well. At least, I assume that's why i found one growing out of the dirt floor of the old farmhouse basement, hundreds of feet from the vine. I assume a varmint hauled it back to the house and buried it for future consumption. 

 

This is what it does to our garage

 

Once through, it slithers around inside until it finds the light from the window

[Guest Robin Macson]

Trumpet vine will sucker freely in the garden so use caution about its use in small space gardens.

[Janet Macunovich 32]

Wow, DSmith, those are scary photos! And I was already scared of trumpet vine.

[Dsmith74 16]

Yup! I would not put it on a house. That's an outbuilding, not attached (or even near) the house. And those vines are from when I wasn't in charge of maintaining the place. Had I zoomed out, you would see that they are cut above and below those photos. I just can't get those pieces out without tearing off the siding. I would never plant it again, but it's been there for decades, the hummingbirds love it, and it looks cool because you can only see the top with the flowers peeking over the roof from the house so I just keep hacking at it when it misbehaves. 

 

I did order some Bignonia capreolata, which I have never tried before, for my own (new to me) house in town to see if it's a suitable alternative.  Also some Parthenocissus henryana to see how it does compared to quinquefolia, which also used to grow on that building, but I couldn't keep it off the power lines to it's gone. 

[Janet Macunovich 32]

We'll be glad to hear how the Bignonia and Parthenocissus work for you. We've never planted crossvine (we've just never had places for such big things, or on the big properties we've worked, enough nerve to try them; maybe here on its northern edge crossvine won't reach 50' but we saw it that big in Louisiana -- and suckering although we couldn't say it was as bad as trmpet vine -- and can't get that image out of our minds.) The silvervein creeper's news to us -- unless it's one we saw and thought was a Virginia creeper variety, at Hamilton RBG. At any rate, we are always glad to hear about new things that work.