Which Climber is Best for A Garden Koi Pond Pergola?
QUESTION ... I have a pergola over my Koi pond, approximately 18ft x 6ft. I had honeysuckle climbing up and over the pergola, but then red berries appeared and I was informed that they were poisonous if they drop in the pond. I have just lost a Koi, and now wonder if the berries were to blame. If this is the case could you suggest an alternative climber for the pergola, which will be none toxic to my fish?
Mr T W Alty, Liverpool
A: Many of the honeysuckles do have berries that have a very heavy emetic, purgative and laxative effect on human beings. So it is quite possible that they would be quite poisonous to fish. Look for signs of sickness in the other fish too. Honeysuckles or Lonicera are very messy plants at the end of the season and also seem to carry a lot of fungus and mildew which sometimes affects other plants around them, although shouldn't be harmful to wildlife.
Plants for pergolas is a perennial question and it was always difficult to make any suggestions that will appeal to the gardener or plant lover but also not interfere with the balance of the pool environment. All plants drop their leaves at some point, even evergreens, and all flowering plants drop their flower petals and berries.
I normally suggest Ivies particularly the fast growing and flamboyantly variegated Hedera canariensis varieties. These hardly drop their leaves at all if the are healthy and, if they are kept in order, rarely flower. If they do flower, there are no petals and the flowering limb can be pruned off before berries form. These too are a mild purgative, but they dont drop as readily as honeysuckle berries.
Now that skimmers are becoming part of the Koi keepers usual kit and with the advent of in-pool type of skimmers from the likes of Oase, it doesn't really matter that a few leaves or petals fall into the pool. Clematis montana, or the evergreen C. armandii make perfect fast growing cover and lend themselves to a Japanese atmosphere. For something a bit Mediterranean,how about a grape vine or two or more. Now those berries are definitely not poisonous and collecting them will be a pleasure!