Hi,

I'm a newbie on a quest for pond plants the like (or tolerate) water with a high pH (8.2) and can tolerate temperatures down to nearly freezing in the winter and up to 80F/25C in the summer. The Koi in my pond seem to be OK with the high pH, and after a year of adding vinegar to lower the pH, I am considering just living with the high pH.

Some background information, the pond is about 1 year old, its 4000 gallons, its a liner with concrete (and the concrete surface was sealed). The filter is a bio-mat with volcanic rock and water is pumped into a bog pond area and then flows down into the main pond. Pretty much all of the plants in the bog pond have died off (last summer), and I've been told its because the pH is too high.

Any recommendations would be greatly appreciated!
Thanks
Dave

I'm afraid that I don't know much in this area. My pond is near neutral and from the well, the pH is 6.5 (going to 7 with aeration). I've never really looked into high pH tolerant pond plants. I think some of the submerged plants like anacharis and hornwort might do ok. As for marginals, I really don't know. A lot of what they experience comes from the soil and air, not just the water quality. Usually, you would talk of the pH of the soil and not the water so much. There are many low pH box-type plants but I'm not sure about the other extreme. For now, at least you know which ones haven't done well so it may be a process of trial and error. You said "pretty much all the plants" died. Does that mean some survived? Is the bog made of a large area of dirt or gravel or are the plants potted? If they aren't potted, doing so may reduce the effect of the high pH flowing through the plants' roots. I hope someone will read this who has a high pH and can offer some ideas.

The only plants that survived were the equisetuum (horsetail) in the bog pond area (and of course the string algae). And the equisetuum is barely making it, definitely not thriving. Water lillies in the main pond (in pots) would shoot up lilly pads but they would turn brown in a day or two (last summer).

Hopefully someone has some suggestions?

Thanks
Dave

I hope someone will reply to your question/dilemma Dave.

I also have a concrete-lined pond with a pH over 8.0. It would be great if all the folks out there with concrete ponds would keep this thread alive with posts about what works and what doesn't.

All of my pond plants are planted in garden soil, except for a water lily that is in a basket with 'acquatic soil'. My pond is new, so none of the plants have been in the pond for more than 6 months. Here are the results so far:

Corkscrew rush - declined steadily until removed.

Marsh Pennywort - thriving, with branches/roots extending two to three feet out into the pond. This is where fry hang out in my pond.

Golden Moneywort - thriving in bog area

Japanese Iris - languished for several months, but then recovered and seems to be thriving.

Water Hawthorn - thrived initially, but then died back about half-way and is now stable at the smaller size (about a dozen leaves).

Water Lily - too soon to tell. Four of its pads have yellowed and died, but it keeps putting up new ones, and is about to put up its first flower.

Fiber optics grass - surviving fairly well in bog area, growing slowly

Dwarf parrots feather - surviving, but not thriving

Dwarf papyrus - new growth seems stunted, but this one doesn't have much soil to grow in.

Dwarf cattail - surviving, but not thriving

And lastly ... String algae - thrived magnificently for 6 weeks in spring, then died back almost completely

I have 8.5pH tap water too. I lower it to 8-ish for my pond and several tub lilys I have. When I started my small pond this past spring, all I put in were 2 sarasso comets, a water lily (red, never checked the type but it is a separation from one of my tub lilys), 3 anacharis sprigs (from local pond store) and 1 small water hyacinth (from local pond store).

As of right now, the water lily is a mess from an animal attack. Prior to that it was blooming pretty consistently. 2 blooms in a row, then a week with nothing, then 2 more in a row, etc. This is exactly as the parent that is in a tub always has done through the summers. I suppose they're pretty happy with 8.5pH. I do fertilize the lilys with one tablet per gallon of soil every 60-90 days (when growth seems to slow).

The anacharis is crazy. I have to pinch it off almost weekly to keep it from overgrowing the entire pond. Apparently it loves the high pH. :blink:

The water hyacinths are suprisingly restrained. They are by no means unhealthy, nor do they have a problem growing and multiplying. The thing is, they seem to be a little retarded by the higher pH compared to the stories I've heard from others. 1 plant has turned into 4 separate plants since spring with a few still connected to their parents (about 10 total plants). I'm by no means complaining, it's less hassle for those nice blooms they give. :D

Oh ya, and I have string or 'hair' algae, but not in excess. It grew up while the plants were taking hold (open sun), and between the shade that has come in from the plants and the fish nipping away at it (do snails eat algae? I have a few small local snails that made themselves a home in the pond too) it's not completely gone, but very managable. I've only pulled some out that grows around the anacharis and lilly stems.

Thanks for the information, Mike. I never did add anacharis to my pond,
but now I might give it a try! Don't mind pinching back.

I added Water Parsley early this summer and it is also doing fine with my
high pH.

I wish my lily bloomed as much as yours. Only four blooms all summer,
and none in the last month, so I think it is done for this year. Is yours
planted in regular dirt or "aquatic soil"? I'm thinking of replanting mine
in dirt while dormant this winter.

It's in a yellow clay based medium. Pretty interesting stuff that my local pond store sells their aquatic plants in. It holds a nice tight pack around the base of the tuber (I think that's what it's called) of the lily and doesn't tend to stir up a lot if you move it around. When I replant them (rarely) I keep the clay core and put some of the aquatic soil around that. I always press the fertilizer tabs into the clay though, even after repotting.

I just moved my pond lilys inside for the winter (I added two more since the last post, a pink from one of my tubs that got a leak, and a yellow from the store). I'm waiting to see if the pond ones start blooming again with the warmer temps in the house. My normal tub lilys usually don't, I'm just wondering if the pond environment makes a difference. :)

I also brough the anacharis and one of the more prolific hyacinths in. The anacharis has been inside my winter tank for a week (same water conditions as the pond for the pond fish to winter in) and has grabbed hold and grown quickly, two have grown over an inch already. hehe