koi pond pergola

by Cindy
(Clinton, PA)

Hello. We are from southwestern PA and built our pond 4 years ago. We have no shade in the yard and, therefore, an ongoing battle with algae. Pond plants have had a difficult time growing (I'm not exactly sure why) big enough to cover a significant amount of the pond's surface, and the expense of replacing them each year is becoming a problem. Overwintering them in a kiddie pool in the basement is not a solution due to the cats, and so the time has come to erect a pergola to improve the site and help the algae situation. My questions now involve which vining plants to situate on the ends of the pergola which will provide the needed shade but not drop anything into the pond which might be toxic to the fish. Although the pergola is providing cover for the pond, the end posts will be in contact with both pets and humans. and so I will need to use something that will not cause any type of skin reaction/irritation. I had considered using Trumpet vine because of the beautiful flowers, but then eliminated it because of this problem. I would appreciate any info you have to offer, and thank you very much for your time.

Doug says there are several questions here. The first is about the construction material. I'd use a straight cedar post if you're concerned about toxic materials. Nothing there is going to bother plants, animals or people to the best of my knowledge.

The second is about the climbing plants and the sky is the limit here. You want something that doesn't drop "stuff" so let me suggest clematis and roses. You can grow climbing rose and clematis right together up a trellis. The roses can be trained to the trellis and the clematis will make use of both the trellis and rose to twine around. You get both the long-blooming color and fragrance along with some serious color choices here.


If you have ongoing algae problems - you have an ecologically unbalanced plant and water combination. There's no nice way to put this - but when this ecological imbalance is created, you get algae - it's a management or construction issue and not one of too much sunshine.

It's entirely fixable but it depends on what you're doing. If you have too many fish in the pond, they'll eat the plants. (remove fish to acceptable limits) If you don't have enough hardy oxygenators - add them. And with the combination of the right level of fish and the right number of oxygenators (see relevant pages for details) then the balance can begin. If you don't have enough of the pond surface covered with plants (hardy lilies etc) then you'll have algae.

So - my main recommendation around the algae is to read the algae pages and get a handle on what causes it and how to fix it naturally. It's quite doable but far too big a topic to cover in a single answer.