California Concrete Ponds. Plants and Planting Depth
Peter--I'm a bloke in Southern California...I've inherited a 15" pond--4feet wide and 8feet long. I'm not going to have fish. I've tried that and the animals in our kingdom gobbled them up. No, I'm going to put a beautiful stone piece in the center and fill the pond with water and plants. But most plants I want to get say 18 to 24 inches depth.. Is there any hope save tearing it up (it's concrete) and making it deeper. Are there plants I can use in this pool? If I don't have fish do I need and filter? Thanks for your help..Clyde .
Hi Clyde ... the most important ingredient is oxygenating plants. i.e. any plants that have submerged foliage. The best is Elodea crispa/ Laragasiphon major. THis will provide oxygen for the bacteria in the pool that digest organic matter, breaking it up into nitrates that will feed other water plants.
Next - depending on whether your stone feature spout water or not - you want some deep water plants. Ideally these would be lilies which would provide cover, thereby starving out the algae and use up the excess nutrients from decaying organic matter. These will not survive continual splashing from a fountain. Water hawthron - Aponogeton distachyos, yellow brandy bottle - Nuphar lutea, will though.
Other plants that will grow up from that depth are Pontedaria coradata or bog bean - menyanthes trifoliator bog arum - Calla palustris, Iris pseudacorus - the yellow flag Iris. The arum lily - Zantedeschia aethiopica will come up from 9ins below the water line. A classy addition to any pond.
Other plants could raised up in baskets on bricks. Aim for two thirds pond cover. If you dont fancy this then you must resort to a biological filter I'm afraid. There is a complete directory of easily obtainable plants and their specs in my new book 'Designing and Creating WAter Gardens' available from Amazon.
There are other plants like the Typhas or reed mace or the common reed or some scirpus(bulrushes0 and horsetails. Avoid these unless you want to dredging out masses of root growth every fall.