Do you even know what a pergola is? I didn’t until my wife said she wanted me to build one. She figured it would be a nice afternoon project. A month later and many hours of work later, it was done. It was done all in wood, but they also done in metal. Bel Air Stairs & Railings ( http://www.belairstairsrailings.com/ ) has made some nice ones.
A Green Roof
OK, so what is it. It is a rigid canopy to shade a deck or pool area (not over the pool). There is no roof over it per se. It has pillars and then a frame over the top. It can almost look like the joists supporting a floor or ceiling, although more decoratively done with the ends usually cut in a fancy way and routed to look pretty. Or it can be a lattice work of metal, either flat or curved.
Well, this doesn’t seem like a good way to create shade. But, you get green shade. Vines are planted around the posts that support the pergola and the vines grow up and cover the top so you not only have the shade from the leaves but the cooling effect of the plants instead of heat radiating down from some roofing material.
Weeds or Vines?
But here is where you have to be careful. Some vines can be more weeds than decorative plants. Trumpet vines can be very pretty but they are very intrusive. Their roots go deep and wide. When we first moved into our current house we discovered a plum tree buried under trumpet vine. Getting rid of the trumpet vine was a major struggle but we have mostly succeeded. The plum tree is much happier.
Wisteria can be similarly problematic. In some ways more so because most vines if you cut the stalk will die out. Wisteria can be cut and sometimes keeps living up in the tree despite being cut off from its roots in the ground.
I went to a flower show at LaDew Gardens where nurseries from all over the East Coast came to sell plants. One booth had trumpet vines, wisteria and other vines I knew to be invasive. After all the trouble I had had with them I was a little miffed that he was selling them. I asked him why and his answer surprised me.
Not All Varieties Are Created Equal
He said that it depends on the variety. He knew that some were horribly invasive and he didn’t sell those varieties. He only sold varieties that were well behaved and stayed put and didn’t spread like crazy. Oddly he said that sometimes it was the native variety that was well behaved and with other species it was the non-native variety that was well behaved. You just needed to know which was which and plant the right thing. So if you are thinking about a pergola, give Bel Air Stairs and Railings a call and also check carefully about the plants / vines that you plant.