Caltha Cowslip Info: Tips For Growing Marsh Marigold Plants

Caltha Cowslip Info: Tips For Growing Marsh Marigold Plants

By: Becca Badgett, Co-author of How to Grow an EMERGENCY Garden

Gardeners living in mountainous areas of the upper southeast and lower Midwestern states may notice perky yellow buttercup-like blossoms springing up from April to June in moist woodlands and boggy areas. Likely you are seeing marsh marigolds, which may lead you to ask, exactly what are marsh marigolds?

What are Marsh Marigolds?

Not related to traditional garden marigolds, the answer is Caltha cowslip, or in botanical terms, Caltha palustris, a member of the Ranunculaceae family. More detail to what are marsh marigolds includes the fact that they are herbaceous perennial wildflowers or herbs.

Not a traditional herb, however, as leaves and buds of growing marsh marigold plants are poisonous unless they are cooked with several coverings of water. Old wives tales say they add the yellow color to butter, as they are a favorite of grazing cows.

Caltha cowslip is a 1 to 2 foot (0.5 m.) perennial with a mounding habit and is a succulent. The flower color on growing marsh marigold plants is on sepals, as the plant has no petals. Sepals are borne on waxy and attractive green foliage, which may be heart shaped, kidney shaped, or rounded. A smaller species, the floating marsh marigold (C. natans), grows in more northern areas and has sepals of white or pink. This species has a hollow stem which floats on water.

These plants make great additions to the moist garden, and as a bonus Caltha cowslip attracts butterflies and hummingbirds.

How and Where to Grow Marsh Marigolds

Growing marsh marigold plants in moist woodlands and near ponds is simple and marsh marigold care is easy to nonexistent. The Caltha cowslip basically takes care of itself and is suited only to moist areas with well draining soil. In fact, any moist or boggy area is appropriate for growing marsh marigolds. When you are growing marsh marigold plants, don’t let the soil dry out. They will survive drought conditions, but go dormant and lose their leaves.

Seeds for propagation of the Caltha cowslip form near the end of the bloom period. These can be collected and should be planted when ripe.

Now that you know the ease of marsh marigold care and where to grow marsh marigolds, try adding the Caltha cowslip to a moist area in your woodland or natural area.

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Marsh Marigold: Planting Tips

Marsh marigold is prolific plant that likes the margins of ponds and streams. A marsh marigold is quite happy growing in 6 inches of water.

Propagating Marsh Marigolds

To grow the marsh marigold from seed you really need to have your own ready seed supply. The seeds are best planted when they are freshly matured from the plant. Seeds collected from wild plants are often good enough to grow and you will be able to see from the parent plant what yours will grow to look like.

As soon as the seed is ready it needs to be planted in a good quality seed compost or a healthy and fully decomposed garden compost. Plant individual seeds in pots and keep them well watered but also ensure that the pots are well drained. Once they do germinate the plants do very well and can be transplanted.


Plant the potted seedlings in early spring to mid summer, as soon as they are about 2 inches tall with at least four healthy leaves. The seedlings must be well watered until they are established. Since marsh marigolds do very well in the margins of ponds and streams you can safely plant them along a backyard water feature. If you have an area of boggy ground, they will also do very well there. Like most marigolds the seedlings will grow readily and will need little attention once established. Unlike many marigolds, the marsh marigold does very well in the shade.

Splitting Mature Plants

In the spring before the growth really gets started you can carefully dig up some mature plants. You will see that they can be split quite easily into two, three or even more separate plants, each with its own root network. Split the plant as seems best and also remove some of the bigger leaves. Removing the bigger leaves will reduce moisture loss through the natural process of transpiration. Transpiration is almost like sweating in people. It is a side product of photosynthesis and helps to cool the leaf down and control the chemical reactions taking place to convert sunlight into sugars. Removing the bigger leaves will also encourage the newly created small plant to put its energy into reinforcing the stem that has been split and replacing the missing leaves. The divided plant can be planted in the same conditions as the seed grown plants but will be able to grow much quicker because of the mature root system that it already has.

The marsh marigold is a delightful plant that will add color and mark the boundaries of boggy sites within a garden. Used as a liner for streams and drains it is also a useful marker to indicate any adverse developments in the water supply to an area served by the streams. Because the marsh marigold is not a very hardy plant you should make a point of collecting and planting the new seeds as they mature if you want to maintain a good supply. An early frost can kill off all the plants in an area if they haven’t already gone dormant in the soil.

1. Marigolds Are Easy To Grow

The first reason that marigolds are such a popular choice is that they are so easy to grow.

Marigolds will grow in a wide range of soil types and conditions. All they really demand is plenty of sunlight. As long as you plant them in areas of full sun, they should be particularly trouble-free plants.

Marigolds can be started from seed around 4-6 weeks before the last frost date in your area and will usually germinate within 1-2 weeks.

If sowing seeds yourself seems like too much work (or you have left it a little late) then you can also consider picking up inexpensive bedding plants from a local garden centre or plant nursery.

Once you have bought marigolds once, you can let some of your plants go to seed, and they should readily self-seed throughout your vegetable garden and pop up the following year as sort of ‘wanted weeds’.

If this more natural and wilder approach does not suit your style, you can also easily collect your own seeds. You can then sow them and plant them where you want to next year.

Caltha palustris

Caltha palustris, or Marsh marigold, is a native rhizomatous herbaceous perennial in the buttercup (Ranuculaceae) family that can be found from Newfoundland to Alaska south to Nebraska, Tennessee and North Carolina. The common name, Marsh marigold, is misleading because it does not look like, nor is it related to, marigolds.

Marsh marigold is perfect for water gardens, pond edges, rain gardens, and wet, boggy areas in the landscape because it requires constant moisture and tolerates wet soil. It is an early bloomer in the spring with striking yellow flowers on tall, 12 to 18 inch, hollow, branching stems. For best flowering, you should site the plant in full sun, however, full sun in the summer may force the plant to go dormant. This can be rectified with a site that provides some afternoon shade in the summer. Marsh marigold is low maintenance, easy to grow, and will spread in your yard by seed or by division of rhizomes dug up in the fall and replanted in early spring.

It is listed as endangered on the North Carolina Protected Plant list.

Marsh marigold is deer resistant. It can also be a greedy plant, inhibiting the growth of nearby plants, especially legumes. Caltha palustris can be confused with Ficaria verna and Geum radiatum. Ficaria is weedy, but Geum radiatum could be considered an alternative.

Under proper conditions, early spring greens gathered from the plant are edible. To properly prepare the greens, cover the young leaves with 2 to 3 changes of boiling water until the leaves are barely tender cut into bite-sized pieces, salt lightly, and cover with butter and some vinegar. You can also pickle tightly closed flower buds in vinegar, which can be substituted for capers, after covering with boiling water as described above.

Diseases, Insects, and Other Plant Problems:

No known serious insect or disease problems. Susceptible to powdery mildew and rust.

Whole plant near the water. BerndH CC BY-SA 3.0 Flower H. Zell CC BY-SA 3.0 Whole plant Michael Gäbler CC BY 3.0 Leaf Blade Alpsdake from Wikimedia Commons CC BY-SA 3.0 Whole plant Alpsdake from Wikimedia Commons CC0 Emerging Flowers Alpsdake from Wikimedia Commons CC BY-SA 3.0 Cluster of Flowers Alpsdake from Wikimedia Commons CC BY-SA 3.0

Marsh Marigold Care - How And Where To Grow Marsh Marigolds - garden

Marsh marigolds are early flowering British native spring perennials that bring a splash of colour into the garden from as early as February but are at their best in April. They will give a second flush of colour in August if the plants are trimmed back after their first flowering, and we’ve even had them in bloom in October!. They have Yellow buttercup like flowers with glossy green leaves making a spectacular addition to pond margins and bog gardens and quickly grow to form large clumps which are easily divided to provide new plants in spring or autumn.

Calthas (Marsh marigold) grow well as either marginal or bog garden plants making them very versatile. As marginal plants they will grow up to 20cm (8ins) under water and can grow up to 50cm (20ins) in height. A valuable plant providing early nectar for bees and butterflies emerging from hibernation.

Please note they will usually be cut back in May after flowering to encourage secondary summer flowering and may be cut back in summer as they can be prone to mildew and we don’t spray for this.

Caltha a yellow flowered plant palustris of the marshes

Height: 30-60-cm

Planting position: Pond marginal shelf up to 20cm deep or very wet soil

Form: 9cm in a solid pot or 1 litre in an aquatic basket -please select size below

Landscape Uses for Marigolds

Marigolds make nice border plants, but their hot colors should be used with discretion. They work best with either other hot colors, like yellow and orange daylilies, or with complementary purples, like salvia and verbena. Because they are short plants, marigolds are generally used in the front of a border or in containers.

French marigolds are reputed to have some pest-repelling qualities and used to be considered an invaluable flower for the vegetable garden, but there is not a lot of evidence that they actually repel anything except nematodes. Still, they add a lot of color to the vegetable garden. You may have some luck planting marigolds around the edges of my vegetable garden, to deter rabbits.


Chokecherry (Prunus virginiana) is a small--up to 30 foot--tree native to Maryland's moist woodlands, stream banks and roadsides, according to the LBJWC. From May to July, it bears fragrant clouds of 3- to 6-inch white flower clusters. The black or red cherries that follow become increasingly sweet as they ripen through August and September. Use them in syrup, juice, jelly and vinegar, but avoid the toxic twigs and leaves. Plant chokecherry in sun to shade and pH-neutral, moist soil.

Marsh Marigold

Other names

Cowslip, Meadow-Bright, Kingcup, May-Blob

Growth habit

Native distribution

Native to the Finger Lakes Region, Newfndl. to AK South to NC & TN Eurasia.


An 8-12" plant with yellow flowers.
Light: sun to part shade
Moisture and Soil: moist to wet soil


Seed Treatment and Storage: seed germinates best if cold/moist stratified for 60-90 days

Biocultural value

The young leaves and stems of marsh marigold are edible after thorough boiling and at least one change of water. Pickled, the young flowerbuds are said to make a good substitute for capers. Marsh marigold was used by the Abnaki, Chippewa, Haudenosaunee, Menominee, and others as both a poison and a food. The Haudenosaunee used the Marsh Marigold to induce vomiting and as a defense against love charms.

The statements above were sourced from:

Native American Ethnobotany Database: http://naeb.BRIT Native American Ethnobotany

Wildlife value

Marsh marigolds are primarily pollinated by pollen-seeking syrphid flies ( Neoascia spp., Xylota spp., and Lejops spp.), although the flowers are also visited by a number of small- and mid-sized bees. Ants (family Formicidae) and cuckoo bees ( Nomada spp.) collect marsh marigold nectar. Mammalian herbivores avoid the acrid leaves.

Climate change sensitivity

Over the period from 1986 to 2015, Caltha palustris bloomed an average of 5.8 days earlier.


Poisonous description

Marsh marigold leaves are poisonous to livestock and humans due to the presence of protoanemonin, an oily toxin found in all plants of the Ranunculaceae family. Protoanemonin is released by damaged plants and can cause skin irritation. If ingested, it can induce convulsions and lesions throughout the digestive tract. Young plants are less poisonous than mature ones.


Source of plant

Shady Oaks Nursery, Bluebird Nursery Inc., William Tricker Inc., Panfield Nurseries Inc.


Graceful mound of shining rounded leaves is topped with brownish branching stems covered with single flowers filled with rich yellow stamens. Plants 18" tall.

USDA Hardiness Zone

Special characteristics

This showy flower carpets wetlands throughout early spring. The petals, which look bright yellow to humans, actually appear purple to bees.

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