I want to describe some of the garden plants for wet garden you can grow next to a pond or in any dampish spot in your garden.
The problem I had was in choosing which ones to write about; there are just too many great ones that deserve a spot in your garden.
The only criteria I used was that these garden plants be readily available in garden centres; there are many (like the specialist pitcher plants) that are only available through plant societies. So, without further fuss, here are my favourite perennial garden flowers for a wet garden.
One of the best has to be Aconitum or Monkshood. This plant does extremely well in damp, rich soils and the beautiful blue or blue-white blooms are a favourite of the early to mid-summer garden.
Plant in full sun and fall in love with the 4 foot tall flower spikes. It is best to warn you that this is a poisonous plant but unless you are in the habit of munching on your plant roots, (and to some extent the leaves of these garden plants) it won’t bother you at all.
The most commonly available species is A. napellus and its varieties but often you’ll be able to find the rarer yellow flowering A. lycoctonum in specialty nurseries. Both are quite hardy into USDA zone 4. These perennial garden plants are often sold and described as being shade lovers but I have found them to be quite leggy in the shade.
The entire Actaea family is well suited to wet soils. Now that the botanists have moved Cimicifuga into the Actaea family, we’ll have to remember to include this in all discussions of bog or wet area garden plants.
The Cimicifuga racemosa (Bugbane or Black Cohosh) is a North American native and its 5 to 6 foot tall flower white flower spikes are a distinctive mid-summer accent to any shady or part shade garden.
A shorter form A simplex is often available through garden centres and it too is easy to grow and quite hardy.
Most of the Aster family, are, believe it or not, great garden plants for damp soils. Even though we mostly see them growing in drier soils, they thrive in the richness of the bog.
You’ll have to control their growth by spring division as they respond to the fertility and water with rampant growth. This is true for both annual and perennial forms of Aster.
It’s pretty difficult to ignore either of the Astilbe or Astrantia family in any discussion of bog type plants. I’m going to. Most garden writers wax poetic about them but you can find them in any garden centre and they grow well almost anywhere.
Boltonia is a summer blooming plant that loves the moisture and should be grown in more gardens. It resembles a dainty aster plant with billows of flowers. You’ll find varieties in white, pink and violet shades.
Grown in the full sun, these North American native garden plants reach 3-5 feet tall depending on variety and is well worth growing.
Camassia bulbs are sometimes found in better garden centres or catalogues and I’d recommend them just about any day for the adventurous gardeners. Hardy, native, pest-free with wonderful blue flowers these bulbs are impossible to kill in the bog garden.
If you get hungry, you can even eat them as they were part of the staple diet for the native population.
In the past I’ve written about another blue plant – the Campanula family. They also do quite well in boggy conditions besides being great garden plants.
I have three species of Chelone (Turtlehead) in my garden and I like them all. They grow best in a sunny bog and they flower (white, pink, reddish-purple) very late in the season when most plants are considering going dormant for the fall.
Growing between 2 to 3 feet tall (mine consistently hit 3 feet) they are good cut flowers as well as good garden plants. I’ll be dividing mine like crazy this fall to move them from the main border into the new bog garden as a featured plant.
You’ll find C. glabra (white or rose tinted flowers), C. lyonii (reddish purple flowers) as well as C. obliqua (red-purple but early than C. lyonii) in garden catalogues.
Coreopsis. Interestingly enough, Coreopsis verticillata and C. rosea grow very well in wetter gardens. They like having wet feet. I’ve mostly grown these in the main perennial border but will be giving them their opportunity this fall to enjoy a wet spot. Grow these forms of Coreopsis because they flower the longest (almost all summer) and are the hardiest. Other species such as C. lanceolata and C. grandiflora will survive in the bog but are comparatively short lived.
The various Filipendula (Meadowsweet) species also grow well in our wet garden. I have a few that have been clinging to life up in a dry shade bed (yes, I know that’s the wrong spot, but I like to experiment) that I think I’ll give another chance at a good life. I do like Filipendula ulmaria ‘variegata’ and I’m looking forward to seeing what will happen when I give it the conditions it prefers. Any of the Meadowsweets will do well in the garden.
Who could grow a good damp garden without adding Gentians to the plant palette? These blue-flowering sweethearts are the queens of the garden and deserve a prominent place. You’ll find G. asclepiadea (Willow Gentian) in better garden centres and if you plant it in a shady damp garden you’ll be rewarded with the bluest late summer flowers you’ll ever want.
G. andrewsii is going to be harder to find but equally worth the search. It loves the acidic soils of bog-side gardens and its stout flower stalks will grace any bouquet (if you can bear to cut them).
Daylilies. No garden would be complete without Daylilies or Hemerocallis. Blooming in mid-summer for us here in zone 4 (and evergreen and longer blooming in warmer climates) these hardy plants will grow anywhere. It’s a good thing too because they’re going to form the backbone of my new backyard pond and garden design.
Stella d’Oro is a good everblooming variety in warmer areas than ours; here you only get one bloom unless it’s a long and warm season. You can obtain collections of older varieties for a few dollars apiece while the newer hybrids will set you back a bank loan. Look for the fragrant forms like the old H. flava (Lemon Lily) – you might as well enjoy the fragrance while you’re swooning over the abundance of blossoms.
Hibiscus. I bet you didn’t know that hardy Hibiscus make wonderful wet garden plants. I’ve grown these in wet areas, damp areas and bone-dry gardens and the best flowers are always in the wetter gardens. A common name for the Hibiscus moscheutos (the one you’ll find in garden centres) is Swamp Rose Mallow. Now, it doesn’t take too much thinking to figure where to put this plant in the garden.
There are other species Hibiscus that you might find seed for in specialty catalogues. Try them all, they’ll all appreciate the damp.
Hosta thrive in the damp, shady garden. You wouldn’t think it (I’d figure they’d rot) but if you give these guys a lot of water, they grow like weeds. While the green and white common form (H. undulata ‘Medio- Variegata) always grows quickly, giving water to the likes of ‘Sum and Substance’, ‘Elegans’ and H. tokudama ‘Aureo Nebulosa’ will speed up their relatively slow growth. Not only that, but when Hosta are given all the water they want, their leaves become even larger than those you see in catalogues. A situation sure to bring delight to the average gardener.
Inula do very well in damp spots. These daisy flowers live in drier gardens without complaining, but to really see them thrive, give them a damp garden. There are quite a few species of Inula available through specialty plant sources. My personal favourite is Inula royleana – a wonderful stiff stalked plants that holds its 4 inch wide yellow daisy flowers at 24 inches high.
Iris are another wonderful wet garden plant. The beautiful Japanese iris demand constant moisture if they are going to thrive and the bog garden is the best place for them. I’ll never forget the first time I successfully grew these in a bog garden; they were the highlight of the summer. There are quite a few other Iris that thrive in the damp garden, from the Siberian Iris to dwarf I. cristata. Grow them all.
If you are a bit adventurous, you might want to search out Kirengeshoma. This Japanese native has delightful yellow bell flowers in mid summer. It grows 2 to 4 feet tall and will be a central showpiece in the garden. It is not easily found and must be grown in damp soils to survive. Well worth it if you can find it from a specialty gardening source.
Perennial Sweet Pea
Perennial Sweet Pea or Lathyrus latifolia does quite well in damp ground. This is not surprising as it normally seems to be found growing in ditches when it escapes from local gardens. This last sentence should give you a bit of a clue; it self sows and can be a bit weedy once it is established.
You need damp soils to grow Ligularia and you should grow them. Their yellow spikes make a wonderful accent to the damp garden and I’d install a damp garden just to grow this plant family. I have tried to grow Ligularia in regular soils but they wilt so badly during the summer heat it is hardly worth the effort. Build a bog just for them.
Lilies such as L. canadense thrive in damp gardens. Nobody ever seems to mention this in gardening magazines but try installing a few of these next to your pond and create a show-stopping display for mid-summer.
Lobelia cardinalis is one of my personal favourite bog plants. Its cardinal-red flowers are one of the truly red flowers in the mid-summer garden. There are some bronze leaved forms that are not hardy here and some new cultivars that are really annuals (being sold as perennials) so be careful that you get the green leaved form and that it is truly the species.
Gardens that are warmer than mine may be able to overwinter the bronze form or the annuals. I’ve grown Lobelia syphilitica in both bog and desert-dry conditions. It does better in the bog although it will live in dry garden areas.
Lysimachia One word of warning. Some nurseries will sell you perennial garden plants of Lysimachia as bog plants. Don’t let them near your garden! Any garden plant that has Lysimachia as its first name is a spreading, garden thug. You’ve been warned and even if the flowers beguile you and the salesman tells you that you can control it – resist
One of the highlights every year in my garden is when the Macleaya cordata starts to hit five feet tall. Then visitors notice it stuck in the back of the garden, and when the flower stalks stop growing at 8 feet tall, its place as a garden plant showstopper is truly launched. The deep heart shaped leaves and whitish flowers (with cream and pink tones) are instantly recognizable. What is also instantly recognizable is its ability to spread. I’m forever digging its shoots out of neighbouring plants but I love it anyway.
The Mimulus family, or Monkeyflowers, are wonderful wet land plants with their spotted yellow or red blooms. I’ve grown several of these native flowers and can recommend them all. My favourite (besides the annual forms) is M. alutus; well, maybe because I also like M lewisii. Hard to tell which one I like more – I’ll just keep growing them all.
Be careful if you let any of the Monarda family into a wet spot. They’ll love it to the point of becoming a terrible garden thug. There are some wonderful new colours on the market to practice your plant resisting techniques. I obtained a plant called ‘Raspberry Ripple’ last year and am looking forward to its blooms this summer. And no, I didn’t let it into the bog; instead I’ve kept them in the main perennial garden beds.
Some nurseries will sell you Petasites japonica for your bog garden. Their interesting red shoots in the spring (flowering before the leaves emerge) catch the eye. I hope you enjoy them because once this plant gets established, you’ll have the devil’s own time getting it out of the garden or controlling it. Big time spreader! There is a variegated leaf form that is slightly more attractive than the species but just as rapacious.
Physostegia is another of the fine blooming garden plants that will thrive in damp spots. I happen to like this plant although I’m currently trying to dig one variety called ‘Vivid’ out of the main perennial border. These garden plants are rampant spreaders. The showy pink and violet flower spikes will go very well in wild or naturalized gardens although I personally would keep it out of a bog with fine plants.
Most of my varieties are being transferred down to Dug Lake, our large naturalized pond. Physostegia or Dragonhead makes a fine cut flower.
It is hard to know where to begin or stop when I think of Primula in the damp garden. There are fewer finer places to grow these garden plants than in a damp spot in a touch of shade. The vast majority of perennial Primula or Primroses grow best in rich, moist but not sodden, cool soils with a bit of shade from the hot sun. I continue to expand my collection of these garden plants and can recommend more than I have room for.
Easily found, P. denticulata or Drumstick Primula, is an early spring bloomer that will brighten your day with a range of colours – pinks and reds mostly. P. veris is the famed yellow primrose of garden lore and no garden is complete without a huge clump. P. japonica is useful because it blooms for a very long time starting in June and running through July with its tall candelabra type blossoms. You can start these quite easily from seed if you can’t find a specialty nursery in your area.
I have written about P. sieboldii before and I can tell you I’m waiting for spring to see what last year’s seeds will do this year in the bloom department. Its hard to know where to stop: P. bulleyana with its orange flowers, P. florindae a huge version of P. veris, P. mollis with its two toned flowers, P. laurentiana with its bright yellow spring greeting or . . . I’ll stop now.:-)
The ornamental Rhubarbs, Rheum are quite the garden plant bog lovers. I have some seed I’m about to try this year because I lost them last year by not growing them wet enough. You’d think I’d learn by now – some plants just have to have damp soil and this may be one of them. Great huge leaves on this garden plant will make it a showstopper in my perennial garden if I can ever coax it through a winter. (Since I wrote this – I’ve overwintered it successfully – the damp soil was the key in my perennial garden) 🙂
I want to briefly tell you to find and grow every kind of Rodgersia you can. It has wonderful flowers and wonderful foliage. This is a garden plant for all seasons. Enough said.
Two years ago, I obtained about ten varieties of Sisyrinchium (Satin Flower or Rush Lily) to play with. These short (6″tall) spike-leaved semi-hardy perennial garden plants resemble short iris and are simply adorable scattered around the front of the bog garden. I’ve grown mine in different places in the garden but the best results seem to be where the plant can obtain all the moisture it wants.
Tradescantia or SpiderWort is a winner in the damp perennial garden. This plant blooms almost all summer for me when I keep it damp. The minute I let it dry out, it stops blooming. You would think there is a message here. 🙂 Available in several colours – from whites through shades purple and light pink, this is a great 30″ tall plant for sun or light shade.
These are the basics – there are others and once you get going, you’ll want to collect even more of these great perennial garden plants for wet gardens.