A bog garden is one of two things;
It might be a good ideal to build a sensibly sized area at first, bearing in mind you are going to have to purchase bog plants to fill it and they are not cheap to buy. You will also need to keep it wet and if you are on a water meter it all adds up. You can always enlarge it by simply adding liner the following season and by then you will have mature plants that can be divided up.
Line the area with pond liner,
Fill the area with a mix of topsoil and
Mix the soil you have dug out with garden compost, rotted leaves or any green matter and shovel the soil back over the liner, filling the area to just under the top of the pond liner.
If you are building your bog garden as part of a fish pond, overflowing the pond when topping up will keep the area damp and wash nutrients from the pond into the bog.
When the bog plants start to grow in spring, feed them by adding more compost or other green matter to the surface, don't dig it in, the worms will take it down into the ground.
If the garden is part off or next to a pond with fish, over flowing the water will take some of the waste from the fish into the bog garden soil, best of both world, filtering the pond and feeding the bog plants.
Sandy soil will need a lot more compost added than clay. Not sure what type of soil in your garden, visit my "what type of soil" page.
Over a large area of boggy soil, it is a good idea to place stepping stones through the area to be able to walk over to plant and maintain your bog garden without
getting covered in mud and compacting the boggy soil.
Planting bog plants in containers
A bog garden can also be created in a container, any type of planter that will hold water, plants, and soil will do.
Sleepers lined with old pond liner and filled with soil, look good and constructed to form a seat on top, have the added benefit of raised beds, if a bad back makes bending over difficult, constructing a raised bed is covered on this page of my website
Fill and water the raised bed or container and maintain the mini bog garden in just the same way as described above.
Bog plants can be planted in wet, waterlogged, damp and soggy areas, bringing interest and colour to parts of your garden, where less damp tolerant plants can't be grown.
The flowering season is quite short, but a mix of early and late flowering bog plants will take the season through from May till September and the range of foliage, shapes and colours and sizes, growing from just a few inches tall to over 6ft, more than make up for the short season.
Favourite bog garden plants.
One of my favourite moisture loving plants are Hostas, they come in an wide range of colours, from blue through emerald green to yellow. Try to include some with variegated leaves.
Hostas grow to between 18 inches and 3 feet tall with flowering spikes of bell-shaped blooms in July and August. Slugs and snails love them though, which could be a problem in a wet garden.
Irises are another of my favourites in my bog garden, I have the native Yellow Flag planted beside my wildlife pond, but some of the cultivated versions such as the striking white and gold flowered orchroleuca can add colour to a grey damp area, another irises I like is Purple Glory.
Lobelias with their showy flowering heads are popular too, because these tall plants with their typically pink or red flowers stand will stand out even in a busy planting plan.
'Queen Victoria' is one of the largest hosta varieties, with tall upright beetroot coloured foliage and bright red flowers. Most Lobelia, are not very hardy and depending where you live, may need protecting from frosts.
Primula Candelabra Hybrids - stems with several whorls of flowers in many different colours from mid May into July.
Astilbe chinensis var. taquetii grows about 3½" high, with fluffy rich pink erect plumes of flowers in July & August.
Iris sibirica are popular irises for wet areas, available in a wide variety of colours with intricately marked flowers growing around 3-4ft High.
Ligularia dentata a large perennial with golden orange daisies in mid to late summer.
Persicaria bistorta is a easy plant for any soggy spot, produces several stiff spikes of clear pink flowers for most of the summer.
More unusual plants for a bog garden
I try to stick to traditional bog plants but if you want to try something different in your bog garden planting plan and have a lot of space, try these, Ostrich Feather Fern (Matteuccia), Giant Rhubarb (Gunnera) and Ornamental Rhubarb (Rheum)
The Ostrich-Feather Fern looks very delicate and adds a tropical look to the bog garden, with its tall feathery fronds growing up to 3ft, with a spread of less than half that, making for a very upright plant.
The Giant rhubarb plant, is one of those 'once seen, never forgotten' plants, with its massive, rhubarb-like leaves stretching out 5ft and growing up to 8ft. This bog plant needs a lot of space, so it's definitely not one for a small bog garden.
Smaller varieties include:
G. scabra which grows to a height of around 6ft.
G. magellanica grows to about 2 inch tall
Gunnera, Ornamental Rhubarb (Rheum) is worth considering Its less fussy about its growing environment, tolerating shade and slightly drier conditions.
Other plants I have tried and worth considering for your bog garden include:
'Candelabra primulas', especially Primula pulverulenta.
Creeping Jenny (Lysimachia nummularia), for ground-cover.