Hmmm. Never heard of "climbing" petunias. There are cascading petunias, that I guess would climb if you were to tie them up. I can't picture them climbing without being woven into a trellis, or something like that. They don't have the little tendrils that a lot of climbers have and they also don't have the 'air' roots that other climbers, like ivies have. I usually buy my petunias as plants and I regularly buy cascading ones, as I keep them in containers. I live in OK and the high winds here cause me to move them out of the weather occasionally, so I make it easy so I don't lose them. As hardy as they can be, most of them will not stand up to big rain/wind storms.

If you're going to tie them to your downspout, I would use something like Swift Grips Velcro plant ties. They're gentle to use, reusable and they can be moved as you need to.

I hope your petunias are everything you want them to be.

Here is a link that might be useful: Cascading Petunias

The blurb says they grow to 3 feet so I think scrambling or lax might be a more accurate description. As grandmamaloy says, they will almost certainly need some help in rambling upwards.

I would be leery of anything climbing up a downspout. A rain with water gushing out of that downspout will wash away the soil around your plant and the plant could obstruct the waters flow and direct it back to your foundation and then you have real problems.

If you are planting this climber I'd look for a better place than a downspout

as you know.. our growing season is rather short .... here in MI

so when you read the hype on such.. look to see where the source of info is ...

for us in MI ... maybe.. this thing would get 3 feet tall..

but further south.. throw on a couple extra months of growth ... and all of a sudden.. they are much more vigorous.. eh???

never heard of them... no experience ...

ken

They sell those wire ladders that fit around the downspout, I could just get one of those and easily tie the stems as they grow.

I've grown them many times: they're beautiful and smell wonderful. However, calling them 'climbing' is a bit misleading in my opinion. 'Vining' would be a more accurate description and I believe other companies do sell it under the name 'Old Fashioned Vining Petunia'.

I've grown those petunias the past three years. I think both "climbing" and "vining" are inaccurate. They climb the way so-called climbing roses do: by growing long, leggy, stiff branches that need to be tied to a support. They do not cling or twine at all. Branches which are allowed to flop about will get broken in a strong wind or heavy rain.

They aren't as floriferous as modern spreading petunias. They have more of a wildflower look, with tall stems and a few blooms at the top. This growth pattern does make them cut-flower candidates. Individual flowers only last a day or two. Buds which show color will usually open in the vase. I grow them for their evening fragrance, which beats every other petunia I've grown.

I haven't had diseases on my petunias yet, so I have no idea how disease resistance on the old-fashioneds compares to modern varieties. My problems have been slugs and watering. Have you had problems with other petunias?

Your wire ladder idea is a good one, but I agree with dowlinggram on the downspout. I can't even keep bare mulch under the downspouts here, it ends up strewn across the lawn every time we get a good rain. It would be a shame to have lovely petunias destroyed by a summer downpour.