Changing from pond to bog garden?

[Waterbug]

Bazza, I hope there hasn't been some confusion...you do understand there is a difference between the 2 types of bogs Addy was talking about? The most common term for "bog" in Water Gardening is a lined "pond" filled with gravel so there no surface water showing. These were originally called "gravel filters" but Water Gardeners liked the term bog better. The other type of bog we've had to add the word "true" to as in "true bog". The two are very different.

However, in both cases an intact liner is normally required. A true bog has some needs like specific nutrients and low pH. These can be pretty hard to control without a liner. Normally "true bogs" are kind of an acquired taste.

Poking holes in the liner or removing the liner and hoping for water to collect would generally just be a wet spot in the garden. Depending on depth, there are lots of plants that could be used. Mosquitoes and algae can be a problem with these depending on depth and the amount of rain you get.

If just rain fed and allowed to dry out in the summer it would be called a Vernal Pool. These can also be lovely, but again, specific plants must be chosen and placed carefully. A bit complex to setup but then almost maintenance free.

If you don't want the liner you may be able to sell it on Craig's List. The buyer might even dig it up for you.

 

[bazza456]

Hi Waterbug,

I think you have hit the nail of the head! It sounds like it is a Vernal Pool I am after so many thanks for making the distinction between this and a proper bog garden. What sort of plants would you suggest could be used in this situation?

Best regards,

Bazza

 

[Waterbug]

Kind of depends how far you want to go. Reproducing an actual vernal pool would be a challenge. They are so tuned to local conditions. I only know about vernal pools around San Francisco Bay, I just collected seeds and grew plants but couldn't create a real vernal pool. Maybe you can find some local vernal pools?

If you just want the look it can be forced by creating thin barriers that follow the land contours and planting with low growing flowering plants including terrestrial plants like Alyssum.

You could also just plant the whole deal, then fill with water in the spring and let the water evaporate over the summer. Do no maintenance for years and see what nature provides. You could also mess with the pH. I don't think it's just the water level that creates these but also the sudden change in pH between wet and dry areas and how that condenses as the water volume reduces. But I'm not sure about that.

I do think an intact liner would be needed, or at least a big help at creating the abrupt changes in environment needed to stress the plants into growing in bands. And a vernal pool is a stressful environment for plants, it's a requirement.

 

[adavisus]

Vernal ponds are very particular habitats, often listed as protected in the wild

Theres very few plants that cope with saturated wet conditions one season and bone dry the next.

Of the seven temporary vernal ponds here, it's fairly typical for a few toughies like really, really hardy waterlilies to barely sputter into life before drought pickles them in bone dry mud dormancy, spike rush just about hangs in there.

Though, by the time some rains think about damping them a tad, a perty fine crop of grass and weed seeds are well poised to spring to life just in time to root in well in advance of spring

Regards, andy
http://www.flickr.com/photos/21940871@N06/
http://swglist.wordpress.com/

 

[Waterbug]

Bazza, after giving vernal pools some more thought I reread your original post and am thinking you really just want to convert the existing pond into landscaping with minimal effort? If true I can see why you mentioned vernal pools as a choice, because you wouldn't have to fill it in. True?

If true I would remove the liner.

For plants you could use what's called "marginals" in the deepest part These are pond plants that can take being in standing water but are also OK in damp soil, they don't require standing water. It kind of depends on the amount of rain and soil type on how much standing water this will have. I'm kind of assuming there will be 12" of standing water for weeks at a time, maybe months.

Deep parts
Cattail
Umbrella Palm
Papyrus
Pickeral Rush
Lizards Tail

Less Deep
Zebra Rush
Calla Lily
Canna, any kind
Horsetail Rush
Corkscrew Rush
Parrot's Feather
Sweet Flag
Water Clover (Pennywort)

Around Edge
Creeping Jenny
Moneywort
Any Iris
Water Zinnia
Bulrush (short)
Ruellia
Society Garlic

You can also plant a tree like Marsh Mallow, Althaea, which one of my personal favorites.

Most or all of the plants I listed can grow very fast and spread...they can also died out. For example some like Horsetail send out runners and can get into the lawn. Others like Iris, Canna, Cattail spread by dividing and are easier to contain. I also don't know your climate so I had to guess.

The reason I suggested filling the pond with gravel is to eliminate algae and mosquitoes. But you could try just removing the liner and see how it goes. Once the liner is out you can toss any extra soil you have to reduce depth, but I wouldn't use any potting type soils.

 

[bazza456]

Dear Waterbug,
You are bang on - I am a lazy gardener so 'minimal effort' is key to this project. I really like nature to show me the way whenever possible. For example, a couple of years ago I was able to buy a piece of land alongside my house which I have turned into a wildflower meadow which most of the year pretty much does its own thing!
I have decided that I will remove the liner as you suggest but my last question is - when is the best time of year to do this?
Thanks again for all your advice,
Bazza

 

[HARO]

Waterbug; A couple of times now you have referred to the Marsh Mallow as a tree; what do you base this on? Althea officinalis grows to about 4' in height, and is not woody, but rather herbaceous. Could there be a mix-up in identification?
John

 

[Waterbug]

Bazza, text is a hard way to understand ideas, glad we're getting closer to understanding what you're after.

I don't know your climate well enough to answer on timing. But in general I don't much care for most guidelines I hear. Planting an annual a week before frost is probably not a good idea of course. I think it depends on the plant. For example there are lots of time guidelines for planting trees...but what difference is there between the tree being in the ground or in a pot at the nursery? I plant them any time of year, frozen ground excluded, and water accordingly.

I'd remove the liner as soon as you like. I don't see any advantage not to. Sooner it's gone the sooner the soil beneath will get back to doing what it does naturally. Even if you don't plant you'll get to see how much water this spot will hold, give volunteers a chance and you could toss in some seeds to see what happens.

For the most carefree wild look I'd limit the kinds of plants to 1 or 2 kinds. If left on their own 20 kinds would probably become 1 or 2 in a few years anyways. My best guess would be cattails in the center. They have the best chance of staying in the center and hopefully not take over the yard. Not sure how much rain you get. Cattails could be planted any time the ground isn't frozen, but optimal would be spring. Most common Canna, not the true water Canna, normally can't over winter in standing water. But that's hit and miss and in your case Canna might short themselves out water level wise. Kind of vernal pool-ish.

John, yes, you're right. I had to look it up and looks like Swamp Mallow is a more often used common name for Hibiscus moscheutos, which is what I was referring to. When I first learned of these plants people called them Marsh Mallows and it stuck in my head. But it looks like Marsh Mallow a more often used common name for Althaea which is not the plant I've been referring to.

I call them a tree when pruned to tree form. Left on their own I'd call them a shrub. I also like, Hibiscus syriacus for pruning into tree form.