How to Plant & Grow Bog Pimpernel (Anagallis tenella)

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bog pimpernel pink flower blooming
Bog pimpernel is well-loved by humans and pollinators alike for its vibrant, honey-scented flowers. Public domain.

A native throughout much of Europe except the more arid regions, bog pimpernel (sometimes known as “studland”) belongs to the primrose family, Primulaceae. It can also be found in portions of Asia (primarily Eurasia), but is primarily native to Europe, including much of the U.K.

The Anagallis genus (also known as the pimpernel genus) is relatively small, containing only approximately 20 species worldwide. This genus is known for its low-growing, spreading nature and colorful flowers, with bog pimpernel being no exception to this.

Partially named for its preference of damp, boggy environments with acidic, peat-rich soils, bog pimpernel thrives in saturated conditions. Its creeping nature enables it to be trained to drape beautifully over rocks, along pond edges, or along waterfalls (so long as most of the leaves are not directly in the water).

Small, vibrantly pink star-like flowers have a smell reminiscent of strong, fresh honey, and are loved by gardeners and pollinators alike. These flowers typically close at night and reopen each morning, giving rise to their Latin name Anagallis, which has Greek roots and translates approximately as “to delight again.” “Tenella” translates to “delicate,” and is in reference to the plant’s very sensitive flowers that are liable to fall apart if touched or picked.

Facts, Benefits & Uses of Bog Pimpernel

dune slack with bog pimpernel
Bog pimpernel can be found in unique and rare dune slack ecosystems, like this one located in Morfa Harlech National Nature Reserve, Wales. Photo by © N Chadwick (cc-by-sa/2.0)

In nature, A. tenella can be found in bogs, slightly acidic marshes and fens, and other saturated environments with slightly to moderately acidic soils. They can also be found in more calcium-rich, alkaline environments, such as some types of fens as well as calcareous dune slacks, which are incredibly unique, threatened, and species-rich ecosystems found in portions of Europe. These dune slacks rely on species like bog pimpernel that can thrive in low-nutrient, sometimes anoxic (lacking dissolved oxygen) conditions.

Its honey-scented flowers are typically pink, but can be more lilac-hued or white, as well; the combination of their coloration, scent, and rich pollen makes the flowers irresistible and invaluable to a variety of pollinators, including many bees, bee flies, butterflies, and moths. Bog pimpernel is considered critically endangered in nature due to its native wetland habitats being altered or removed entirely, making it illegal to harvest any portion of it in some areas. As much as 99.8% of bog pimpernel populations have been lost in Germany alone.

However, nurseries can legally and ethically grow and sell this plant, and having it in your pond garden can provide a boon to not just your pond, but the local wildlife, as well. If well-established, they can form dense creeping mats that help to hold soil in place and distribute nutrients and keep soil and pond water clean.

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Bog Pimpernel Fact Sheet:
Annual or Evergreen Perennial
H4 (USDA 7-11)
Full sun to partial shade
Pink, purple, white
May – August (Spring to Summer)
Height up to 10 cm (4 in); spread up to .5 m (19 in)
In soil just covering plant’s roots
pH 3.5 – 6.5 (tolerant of shifts beyond this)

Bog Pimpernel Growth, Hardiness & Climate

how to grow bog pimpernel
A. tenella can spread and form thick clumps, but its relatively slow nature makes this easy to control. Photo by Bas Kers / CC BY-NC 2.0

Despite being a creeping plant, the growth of bog pimpernel is fairly slow. Each plant can spread up to half a meter, but it often takes two or more years to achieve this. Its average height is up to 10 centimeters, making it ideal for planting along pond edges or rocks as a beautiful accent. If planted in full sun, you may expect bog pimpernel to reach its maximum size in a year or two, while if planted in partial shade it can take closer to four or five years. Exposure to full sun tends to result in more flowers, while more shade often results in more resources being devoted to creating more leaves to capture energy.

Blooming typically occurs from May through August but can occur earlier or later depending on the location and season’s conditions. In colder regions where significant freezing occurs, bog pimpernel may adapt to be an annual plant, while the higher ranges of its hardiness zone will yield an evergreen plant capable of living many, many years.

How to Plant Bog Pimpernel In Ponds

how to plant bog pimpernel
Bog pimpernel prefers to grow in damp soil, as opposed to directly in water. Courtesy of ceridwen / Bog pimpernel (Anagallis tenella)/ CC BY-SA 2.0

Bog pimpernel is not a picky plant and is typically quite easy to grow. If growing from seed, you can simply sow the seeds in damp (not flooded) soil, and gently press the seeds just very slightly into the soil to help protect them from wind, harsh temperatures, or birds that might eat them. A. tenella can also be grown from division, or buying plants at a nursery. In both cases, plant the pimpernel in just enough soil to cover the roots (or, in the case of cuttings, in about a quarter-inch of soil). Ideally, the soil should be slightly above the water table. Bog pimpernel can handle wet feet, but doesn’t enjoy having wet leaves.

Seeds and established plants should be planted in the Spring after the threat of frost has passed. If you wish to plant from seed but want them ready to bloom in the summer, you can plant your seeds indoors in pots with peat-rich substrate and then transplant any successful plants in the spring. Seeds should not be fully covered with soil, as they need ample sun to germinate, so consider placing the pot in a well-lit windowsill or sunroom protected from the cold and elements.

How to Care For Bog Pimpernel

how to grow bog pimpernel in a pond
Bog pimpernel is low maintenance; it’s content with ample sunlight and moisture. Photo by Velella, CC BY-SA 3.0, via Wikimedia Commons

Bog pimpernel is a rather low-maintenance plant. Simply ensure that its branches and leaves are able to stay free of standing water, and don’t allow the soil to dry out. Access to full sun is best, but partial sunlight that is decently strong for several out of the days will suffice, as well. Full shade is likely to kill bog pimpernel or result in stunted plants without many flowers. To help mimic natural growing conditions, you can add some peat pellets of peat humus to your soil; this will help retain moisture, as well as increase acidity moderately. This isn’t necessary, however, as bog pimpernel can also be found in calcium-rich environments, meaning that they are able to live in more alkaline conditions, as well.

As bog pimpernel is a spreading plant, it is possible for it to form dense mats over top of the soil and, sometimes, the water if any islands of soil are present. However, this typically occurs fairly slowly, and pimpernel does not grow indefinitely, so it’s a simple matter to trim the plant if desired. Take care not to do this too often (only once or twice per growing season, if needed), as frequent pruning can actually trigger hormonal signals in the plant (“Hey! We’re under attack! We have to grow faster!”) and kickstart new growth.

How to Winter Bog Pimpernel

Bog pimpernel is considered to be fairly hardy, meaning its flowers and leaves cannot tolerate significant cold or frost, but it can survive winters if they’re not overly harsh (below USDA hardiness zone 7, or UK hardiness zone H4). A. tenella has adapted the ability to create tough winter buds, which are able to foster new growth in the spring. If you live below USDA hardiness zone 7, consider bringing bog pimpernel indoors for the winter, or covering them in a protective glass house or small outdoor greenhouse structure, if possible, to protect them from the worst of the snow and ice.

Is Bog Pimpernel Toxic, Poisonous or Invasive?

Bog pimpernel is only native to Europe and portions of Eurasia. We do not recommend growing this plant if you live outside of these regions; as with any plant, growing outside of its native region has the potential to result in it becoming an invasive plant that causes significant damage to ecosystems, like out-competing native plants and thus driving out the wildlife that depends on them. Though bog pimpernel is not known to be a particularly aggressive plant, it’s best to only utilize this plant if you live within its native range.

There is very little research into the potential toxicity of bog pimpernel specifically. However, its close relative scarlet pimpernel (Anagallis arvensis) was studied and found to be moderately toxic to mammals and birds due to the presence of toxic oils and saponins in all parts of the plant. Due to its popularity as a pond and garden plant, and the lack of any reported poisonings via bog pimpernel, we determine it to be safe to have around fish and pets, though be sure to remove any fallen or dead leaves and flowers from the pond just to be safe.

Is Bog Pimpernel Edible? Will Fish Eat it?

Bog pimpernel is not considered to be edible, and fish are not known to show much interest in it, though the curious koi may poke at it a bit. The leaves of bog pimpernel do not generally enjoy being in water, so it’s unlikely that your fish will have much opportunity to eat this plant even if they are curious about it. As always, be sure to clean any dropped foliage from your pond to help maintain water quality and fish health.

Where to Buy Bog Pimpernel & Seeds? (UK & US)

Bog pimpernel is most easily obtained from online outlets, though a variety of in-person nurseries propagate it in Britain and other portions of Europe where the plant is native. Be sure to research the nursery so that you know you’re getting plants that are legally grown, as bog pimpernel is critically endangered and should never be harvested from the wild.

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