Montanas can get huge depending on the variety you are planning on planting. According to COTW, rubens can eventually get up to 30 feet long.The stems can look like oversized tree branches with time. If you are planning on planting a montana on your chimney, you are going to need some substantial support for it or eventually it will come tumbling down.

I am a little hesitant however whether to recommend you attempt to grow a montana on a chimney since I am unsure how much heat may radiate outwards from the chimney if it is used for wood burning during the winter. Perhaps this wouldn't be an issue but something I thought I should raise as a potential problem.

If I were going to plant a montana there, I think I would use a masonry bit and drill pilot holes in the mortar, sink lead anchors into the holes and screw eyebolt screws into the lead anchors. Then I would use a heavy duty rust resistant wire to string from eyebolt to eyebolt.

I hadn't thought about the heat issue! I wouldn't plant the clematis until next spring, so maybe this fall/winter I can do an unscientific "feel test" when the fireplace is in use. I do know a 40-year-old pyrocantha was happy there until DH decided it was a weed and hacked it down one day when I wasn't home.

A question about the wire supports -- can a clematis climb vertical wires alone, or do they really need horizontal support too? I have another spot on a NW corner where I was thinking about climbing one up the house, but I couldn't figure out how to wrap a "grid" around the corner. Vertical wires alone I think I could attach to the eaves.

Thanks!

My mom had a pyracantha planted against her fireplace wall also and didn't have any issues with it being affected by the fireplace either but then she had gas logs which were the unvented type. It may not be an issue but just wanted to raise the possibility of an issue. Would sure hate to have a clematis fry from the heat!

How would you fasten the vertical wires to the ground so that they wouldn't sway in the wind?

Interesting question about clematis climbing only vertical wires however. I would think that provided the wire was not super slick, with some reasonable coefficient of friction, that the petioles should be able to grab hold tight enough to climb it and not slide down. You might have issues if the area it is planted in is a windy exposed area.

Another option would be to purchase that green metal vinyl coated fencing at Lowes. Attach it in sections along the corner of the house, wrapping it around the edge of the house. You could fasten it various ways depending on the structure of the house--screws and wiring it to the screws if the house is wood sided or with the lead anchors, screw eye bolts and wire if it was brick or stucco. You could also have it extend outward and not be flush with the house in the case of a wood sided house to allow for air circulation.

Re: the vertical wires -- I was thinking I could anchor them to the house near the foundation, then angle the wires slightly outward and up to the eaves. DH has an aversion to drilling holes in the brick, and I do too in case my clematis scheme is a bust!

Is there a particular clematis you like for house climbing (i.e. not too finicky, long-blooming, and substantial enough to really cover a lot of wall)? I was thinking about the montana because it sounded pretty foolproof, but maybe it's too big a beast for this job. Does it make sense to plant a couple of plants on the same trellis, or will they choke each other out?

Thanks -- sorry for all the questions. For some reason clematis have always intimidated me, but I think I'm ready to take them on.

Iceh, you wouldn't be drilling into the brick, you drill into the mortar in between the brick. They sell mortar in a caulk-like tube at the local Lowes stores in my area in case your experiment goes bust and you want to remove the lead anchors and eye bolt screws.

There are various types of montanas--some that are more restrained in growth size that would be okay but they bloom in the spring and that is it. They bloom on old wood so you wouldn't do any cutting back except to remove old wood and to constrain their growth.

Clematis have a definite bloom cycle time. They bloom and generally speaking they are done unless you cut them back seriously and then fertilize them. You might get some rebloom without cutting back but for the most part, it wouldn't be spectacular. The type IIIs would serve that bill but you would need to cut them back to get them to bloom again.

I do have some type IIs that bloom with an initial big flush and that throw off blooms intermittently over the rest of the growing season. In my zone however 7a NC, they also tend to get a lot of browned out leaves in the heat of the summer.

So the question remains, what is more important to you? Blooms off and on, an impressive display in the spring and no blooms later in the season, having to cut back a clematis to potentially get more blooms, etc?

Personally I would still tend towards the montanas for your situation. They have an impressive show in the spring as they mature. There are a wide variety of cultivars out there available in the US with various types of flower forms, colors, shapes, eventual sizes. An easterly location would give them morning sun and shade during the hotter parts of the day.