Eight plants for water gardens and bogs

Waterlilies make good picking flowers and are often scented, though they tend to close at night.
NEIL ROSS

Waterlilies make good picking flowers and are often scented, though they tend to close at night.

Monet immortalised the waterlily's exquisite form in his oil paintings – and you too can have an Impressionist's garden with a bit of careful planning and planting.

French artist Monet famously said that all he was good for was painting and gardening, and for the last 30 years of his life, as his eyesight failed, he combined both passions by stocking his pond at his garden at Giverny with waterlilies from around the world and capturing them in some 250 oil paintings.

I'm not sure whether Monet was more captivated by the flowers or the reflections on the water to study this singular subject for so long and so exhaustively.

At any rate, the vast, impressionist canvases that he created over that time conjure up perfectly the liquid shimmer and feel of the lazy days of summer, when these exotic-looking blooms – and many other waterside plants – are at their very best. 

READ MORE:
10 pickable blooms to love
Garden of the week: Waiheke
How to use variegated foliage plants  

 
Bridal wreath. This underused evergreen perennial (Franchoa sonchifolia) is from Chile. The leaves are thick, hairy and ...
NEIL ROSS

Bridal wreath. This underused evergreen perennial (Franchoa sonchifolia) is from Chile. The leaves are thick, hairy and wavy, and the flower spikes arise elegantly in summer and leave behind good seedheads through winter. Give it good soil in a semi-shaded site. It prefers a bit of shade where those flower spikes really provide a sense of illumination. Give it a good soil too for the most lush of leaves – they stay evergreen all winter as an added bonus.

Water plants work best when they are established in defined areas.

The waterlilies and lotus belong to the deep water zone, along with oxygenating plants that help keep the water clear and healthy.

Perforated baskets and a heavy loam compost low in nutrients is what they need.  

Dwarf Chinese astilbe, Astilbe chinensis var. pumila, is one of the latest of the Chinese astilbes to flower. It stands ...
NEIL ROSS

Dwarf Chinese astilbe, Astilbe chinensis var. pumila, is one of the latest of the Chinese astilbes to flower. It stands out from the crowd as being one of the smallest in stature but more than makes up for it by romping sideways if you give it the boggy and part-shaded conditions it loves best. Like all astilbes, it doesn’t flower for very long but you do get those lovely ferny leaves and seedheads all winter.

Marginal plants, such as the bold-leafed colocasia and Louisiana irises, like best to paddle at the rim of the pool and are often planted in similar baskets on shallow shelves – very useful for hiding the edges of a pond liner.

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Interestingly, while many marginal paddlers are happy to climb out of the water and grow in the moist garden soil alongside – such as the stately papyrus grass (Cyperus papyrus) – the reverse is not usually true.

Bog plants that thrive in moist soil can be killed if covered in water for any length of time, and are the hardest part of this aquatic plant community to keep happy. 

Hosta ‘Frances Williams’ is one of the big sieboldii hosta, which means you get fairly slug-resistant, crinkled leaves ...
NEIL ROSS

Hosta ‘Frances Williams’ is one of the big sieboldii hosta, which means you get fairly slug-resistant, crinkled leaves and enormous, lily-like, trumpet spikes of flower in summer, which remain through winter as attractive seedheads. These hostas will grow happily even in dry soils once established, but will develop into impressive giants really only in a bog garden.

The problem is that while we want to grow these bold and bright water-lovers, such as candelabra primulas and bold-leafed ligularias, near water, modern pond liners are so very efficient at keeping the moisture in – and the waterside environment can be as parched as the Sahara desert.

What's needed is a dedicated bog area – excavated just as you would a small pond, but with holes made in the liner so that water can seep out and the interior lined with sharp grit and loam soil that is well watered and ready for planting. 

Many bog plants can be pretty invasive, such as the obedient plant (Physostegia virginiana), named for the way the flowers individually swivel when you manipulate them with your fingers.

Great lobelia, Lobelia x speciosa, is a North American perennial that enjoys moist, boggy soils in sun or shade. Its ...
NEIL ROSS

Great lobelia, Lobelia x speciosa, is a North American perennial that enjoys moist, boggy soils in sun or shade. Its seeding habits have produced many varieties including the Fan Series in colours ranging from burgundy to purple, red and white. One of the parents (Lobelia siphilitica) is blue and very easy to grow, but the show lasts only a few weeks and cutting down the plants will not elicit a repeat performance.

This mingles nicely with other equally brutish spreaders such as the white shepherd's-crook flower spikes of Lysimachia clethroides.

It's best to dig out chunks of these each year to keep them from taking over and choking out the more delicate bog plants such as Japanese iris (Iris ensata).

This is the latest iris to flower, with sometimes gigantic blooms that look like blue or purple tie-dyed handkerchiefs.

Gooseneck loosestrife. All the loosestrifes are great bog plants, from the golden creeping jenny (Lysimachia nummularia) ...
NEIL ROSS

Gooseneck loosestrife. All the loosestrifes are great bog plants, from the golden creeping jenny (Lysimachia nummularia) to this more upright coloniser (Lysimachina clethroides). It is found all around the Northern Hemisphere in damp gullies and forest margins. Like many lysimachia this deciduous perennial makes a rapidly swelling clump that is useful for covering heavy clay banks. It throws up the odd scarlet leaf alongside the flower spikes which adds to its allure.

A good complement is another true bog plant: the hybrid lobelia. These spires of lipped flowers come in a full set of colours from pinks to blues, purples, white and red.

Individual plants make a neat rosette of leaf and several flower spikes, but they can seed about prolifically. I cut them down promptly after their brief show of fireworks in midsummer, which is the same time I get to work shearing off the iris leaves before they get covered in rust. 

It pays to keep preening and pruning at the water's edge through summer – even if it is holiday time. The iris will reward you with a fresh set of leaves that will take you through into next year.

Japanese painted lady fern, Athyrium niponicum var. pictum, is a delicate, slow-spreading fern that is ideal for small ...
NEIL ROSS

Japanese painted lady fern, Athyrium niponicum var. pictum, is a delicate, slow-spreading fern that is ideal for small gardens. Its colour combinations of purples and silvers are unique among ferns – pictured is ‘Burgundy Lace’. These ferns hate to dry out. They require shade and a soil that is moist but free draining. Ferns this delicate need careful placement so combine with woodlanders that won’t swamp them, such as omphalodes, ajugas or brunnera.

Make time too to laze alongside any bit of water you can find; marvel at the gyroscopic antics of the dragonflies, the gravity-defying skaters and, if you have a pond large enough, get out your easel and paint. 

WHERE TO BUY:
Parva PlantsWake Robin NurseryWoodleigh Nurseries, Wrights Water GardensWairere Nursery.

Obedient plant, Physostegia virginiana, is a rampantly spreading perennial from America. You can slow it down by giving ...
NEIL ROSS

Obedient plant, Physostegia virginiana, is a rampantly spreading perennial from America. You can slow it down by giving it a heavy soil and less moisture, but if there’s space it’s nice to let it out of the starting blocks. Mix it with lobelias and grasses and let it make a flowery duvet all summer long. White and deeper-pink forms are also available - the white form is useful for not being quite so hell-bent on world domination!

 - NZ Gardener

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