There's no harm in trimming it but there's no need either. This is a rampant grower. Maureen

I'm no expert, but I have a trumpet vine that's been blooming for about 3 years. It blooms on new growth, and it grows so fast that all my blooms end up on the ground if I don't trim it. I decided that from now on I'm going to prune it back severely every spring to encourage blooms throughout the entire plant.
Martha

You can do whatever you want to with this plant and it will make not difference.
Mine came with the house and is about 10 inches in diameter at the base.
I find the vine popping up ALL over the place. 20-30 feet away from the tree... and I think they can grow a foot a day! The seeds will blow over the universe. It attracts ants galore and doesn't pull the hummingbirds the way other plants do. It puts out 'fingers' to dig into wood or brick and pops out of every little crack in the concrete patio. Roundup and brush killers don't hurt it.

They definitely are vigorous little boogers!

Here is a link that might be useful: The Scoop on Trumpet Vines

The only thing this vine needs is gasoline and a match and even that probably wouldn't have any effect. I knew that it was invasive so it was planted at the far end of our yard. No matter, the darn thing comes up everywhere. We have a pool, yard area and 3700 sq ft of deck between where it was planted and the house and I find it coming up from runners near the back door. I'm sorry that I ever planted it. I've been trying to kill it for about 8 years with absolutely no success.

There'a nothing funniner than when folks discuss the "Trumpet Vine"! What a thug! :) Arum

This is not fair! I planted 2 vines in my front garden and it grows vigorously exactly where I put them... but no blooms. And really not much spreading. How do you make the darned things BLOOM?!?!

If you deprive your vine of every comfort - water, fertilizer, space - it will bloom. It blooms faster in sun. Hack it down every Spring, although someone told me this encourages the shoots from the roots. No problem for me - I douse the shoots with roundup and then mow them over. Be sure to talk ugly to it when you pass by.

LOL, julia I love that, "Be sure to talk ugly to it when you pass by."
The first trumpet I planted took about 5 years to flower, then it took over Brooklyn...
Never watered, fertilized, or took any care other than to prune back the whip like shoots in early spring to keep it to a standard/tree shape.
Personally, I'll never plant another.

When I planted mine, I had just the roots that the company sent me. This is now the second year since I planted it, and they are growing fast, but will they have blooms the second year? Has anyone's ever bloomed that soon?

Mine bloomed in its first summer. I was so pleased. But the more I read about it, the more scared I get. I'm thinking bout digging it out and putting it in a pot. Anyone tried this? (Mine is two years old, so pretty small)

Mine took a few years to bloom and by that time I was already trying to kill it, unsuccessfully I might add. That was at least 8 years ago. I've now given up trying to erradicate it and just focus on trying to keep it in one area of the yard (yeah right!). I guess you could try it in a large container. I'd bet that it will find it's way out, even in a pot! The flowers are very pretty though. Just make sure that it gets plenty of sun or you'll just have loads of foliage.
Karyn

I would like to grow it here in the desert - Yuma, AZ area - maybe in a pot? Anybody know if it would survive the 90 degree nights and blazing hot sun during the day?

After talking to a nursery that has a 40ft plus trumpet vine growing straight up an old telephone poll and LOADED with HUMMINGBIRDS enjoying every flower...I found out that
1. You need to give it a place to wrap around so it grows UP not out.
2. If you kill the ants your vine will stop blooming..(not growing just blooming) something about the ants pollinates it.
I'm going to plant my first one this spring and I'm looking forward to it...I usually kill every plant I touch, this will be amazing if it lives!

Yikes all of u have me scared to plant these now ,I just ordered mine and they came in with the green all dryed out and was trying to call company when I came across this website and now I am not sure I want to plant them ,hum what to do :(

docmom, do you like your trumpet vine? How invasive is it in your zone? Are they also called crossvine?

Just received four hummingbird vines (sticks I should say).
Can I plant them in pots to get them started. Do they need full sun to start? Do they need plastic bag covering to retain moist environment? Thank you.

What zone is this plant? I could have swore I saw one growing well here.

My neighbor has a 12 foot high wood fence about 60 feet long. It has a well established trumpet vine that grew over the fence and into my yard to a depth of about 3 to 4 feet and down to about half way on the fence. And had been there for many years. It's full of wasps. It comes up all over my yard so I have to keep putting monsanto stuff on the ones coming up almost every day. My neighbor came to the alley one day and told me I "could trim it back a little if I want to". So well, I can't trim it because it's full of wasps. Made me feel a bit angry, her telling me what I could do on my property..though I didn't comment on it to her. I went to the ciy hall for advice. They said I could spray it and cut whatever I want to to what's on my property. So I sprayed the thing on my side with roundup and then spent $250 having it cut back to the fence so nothing in on my side ...My neighbor is furious and threatening to sue. There is nothing lost since she never speaks to me unless there's some kind of problem. I hate that trumpet vine.
So does the neighbor have any legal case?

I HAVE JUST PLANTED THE SEEDS FOR THE CARDINAL VINE. THEY WHERE UP AND GROWING WITHIN THREE DAYS. THIS WAS IN MY CONSERVATORY. I WOULD LIKE TO KNOW IF THEY ARE EASY TO GROW IN SOUTHERN ENGLAND, ANY ADVICE WOULD BE GOOD. THANKS

This plant is beautiful but it is a nightmare to contain. New shoots pop up everywhere I do not want them to. They are now in my vegetable garden :( and they are everywhere in our grass and flower beds, all from one giant plant. It is impossible to get rid of.

Move away.