For some of us, a walk through the forest in mid-spring may be the best way to enjoy these woodland beauties. But those of us who enjoy a gardening challenge might want to try growing these native North American orchids. With a pouchy flower that looks like a little slipper, cypripediums grow in clumps and colonies.
Lady’s slippers (also called moccasin flower) grow in moist woods, open-forest swamp areas, fens, and riverbanks. They spread by way of rhizomes. They can be found east of the Mississippi River in the United States and north into Canada.
These plants grow in a very specific habitat and are very particular in their requirements, but as long as you can meet these need, you will have success! If you have a shady spot under trees that stays moist most of the time, give cypripediums a try.
Types of Cypripedium
According to the USDA Forest Service, there are 12 species of lady’s slipper orchids in the United States, and there are about 50 throughout the world. Here are a few favorites that are readily available from nurseries that sell native plants:
Cypripedium kentuckiense – Southern Lady’s Slipper is one of the easiest to grow and also has the largest flowers. These yellow beauties are hardy as far north as Vermont. The further north they are grown, the more sunlight they can take. A 6-inch layer of leaf mulch in winter will protect them from cold northern temperatures.
C. acaule – Pink Lady’s Slipper has 3 inch long deep pink flowers and has a sweet scent. It blooms from June to July.
C. reginae – Showy Lady’s slipper grows 1 to 2 feet tall and blooms in late spring into early summer. It has white flowers with pink markings. This one grows in bogs and swamps and would work well in a rain garden.
C. calceolus – Yellow Lady’s Slipper blooms a bright, shiny yellow in early spring. Their native habitat is in woodlands or along the edges of bogs.
C. candidum – White Lady’s Slipper is endangered, but you might find it for sale from reputable native plant growers. This species grows from 6 to 12 inches tall.
Over the last 20 or 30 years, breeders and growers have developed about 130 cultivars of this native plant. Breeders are working to improve its hardiness, decrease its care requirements, increase its flower size, and introduce new colors.
You might also find species from China or Japan for sale, and these plants may have different cultural requirements.
As we’ve said, native lady’s slippers are very particular about their growing requirements. If you can provide the following things, your lady’s slipper orchids should thrive.
These plants are hardy in zones 2 to 8, with the southern lady’s slipper hardy to zone 3. They like a temperature range no higher than 90°F in the summer and need 2 to 3 months below 40°F in the winter.
These plants like a slightly alkaline soil with a pH of 6.5 to 7. The soil should stay constantly moist, but should be well-draining and high in organic matter.
Amount of Sunlight
Cypripedium are shade-loving plants that grow under tall deciduous trees like oaks, beeches, and maples, so plant them in your woodland garden. They can take a little bit of direct morning sunlight, but keep them out of the midday and late afternoon sun. Dappled shade is best as it gives them the bright, indirect light they love.
Please don’t take cypripedium from the wild. In some states, these plants are listed as endangered or threatened due to habitat loss and poaching. They do not transplant well – there is only a 5% transplant success rate – and any plants you dig up will probably die if you take them from their native habitat with hopes of moving them into your garden. It’s better to buy them from a reputable grower or nursery.
Fall planting is best, but springtime planting can be successful also.
Buy full-size plants. Lady’s slippers seeds require a specific soil fungus to germinate and have a poor germination rate even in ideal situations. Even if you are lucky enough to get a plant to grow from seed, it can take up to 10 years to flower.
Determine your planting location. Be sure in this decision because cypripediums do not like to be moved.
Prepare the soil. Loosen it with a garden fork and add a mulch made from composted leaves. Do not over-work the soil – it should be light and fluffy, well-draining, and high in organic matter.
Plant your cypripedium bare root. If you bought it in a pot, gently shake off all the potting medium and lay the roots on the soil. If you purchased it mail order, it will probably arrive bare root.
Spread the roots out on the ground. They are very fragile, so do this gently. If the roots do not spread out in a perfect circle, don’t force them – follow the direction the roots are growing but give them space and room. Then mark the size of your planting hole. It should be a few inches wider than the spread of the roots.
Dig the hole about 3 inches deep. Lay the roots in the hole and position the “eyes” of the plant about 1 inch below soil level. Gently fill in the hole, keeping the soil light and loose; don’t compact the soil. Be sure the growing tip is above the soil line.
Use a watering can to gently water in the plant.
Apply a two-inch layer of leaf mulch, taking care not to cover the growing tip.
Be patient. It might take up to a year to get established and could take a few years before flowering. Over the years, you may even grow your own colony.
Grow these plants in the garden, not in pots. They need room to spread their roots. In their native habitats, their roots travel across the surface of the forest floor, just under the leaf litter.
Paphiopedilum orchids are also known as lady slipper orchids and these can be grown in pots, but they are a different species altogether with different care requirements. Knowing and using the botanical name of a plant is very important!
Cypripediums need the most water when they are in bloom. Do not let these plants dry out, but they shouldn’t be waterlogged either, as that can rot the rhizomes. Water with distilled water or collected rainwater (chemicals in tap water can be harmful) when the top 1 inch of soil is dry.
It is unnecessary to fertilize your lady’s slippers, but some gardeners like to use a 10-10-10 liquid fertilizer diluted at ½ to ¼ the recommended rate once or twice in the spring. Using a rich, humusy, leaf mold mulch will provide the nutrients these plants need.
After cypripedium flowers fade, the flower stalk can be cut down to the base of the plant for a tidier look. As the summer progresses, the leaves will turn yellow. Allow the foliage to die back naturally (as you would with tulip foliage) as the plant goes dormant. This will ensure your lady’s slipper returns next year.
Cypripediums are not troubled by pests or diseases, although white-tailed deer will browse them. The biggest problem lies in recreating their native habitat.
Creating a native woodland garden is not an easy task. It takes a lot of research and dedication to recreate what nature does so effortlessly. However, we can recreate that “look” by planting cypripediums with small hostas, ferns, trillium, bleeding hearts, and astilbe.