<em>Lysimachia</em>: planting, care and propagation

Description and botany

Loosestrifes (Lysimachia in Latin) are hardy herbaceous perennials of family Primulaceae. All particularly appreciate fresh to wet habitats.

Origin of name Lysimachia is uncertain but probably Greek. It likely refers to name of a king or a physician from antiquity.

In English, the yellow species is called yellow loosestrife, literally “yellow loosestrife”. Indeed, resemblance with some Lythrum species is undeniable. Some have erect, very floriferous stems, one yellow, the common loosestrife, and the other pink, the purple loosestrife.

Native to temperate regions of Northern Hemisphere, mainly Europe and Asia, they are very hardy. Hardiness ranges from -7°C to -30°C. With more than 150 different Lysimachia species, they display great diversity of flowers, colours, habit and leaves.

Loosestrifes occur with erect, clumping or creeping habit and bear white, yellow or pink flowers. They flower between June and September. Note white flowering of Lysimachia clethroides while Lysimachia ‘Beaujolais’ flowers a deep burgundy. Flowers may be star-shaped, solitary or grouped in whorls, spikes or clusters. Flowers attract pollinating insects such as butterflies and other pollinators. Largest loosestrifes reach up to 1.20 m like common loosestrife. Smallest are under 10 cm tall with a mat-forming habit such as Lysimachia nummularia, also called moneywort. Taller species are ideal for creating a bright backdrop in borders while mat-forming species make excellent groundcover for damp areas. Erect species can also be used in cut-flower arrangements.

Lysimachia punctata

Foliage is deciduous or evergreen, opposite or whorled depending on species. Leaves vary greatly in shape and size. They may be light green, golden, silver, variegated or purple. Lysimachia ephemerum or willow-leaved yellow loosestrife is arguably one of the most ornamental with its silvery foliage and white flowers.

All prefer rich soils and, above all, consistently fresh to wet conditions. They particularly favour pond edges, woodland margins or wet meadows. Regarding soil pH, they tolerate almost any pH and even ericaceous soils.

Used as an ornamental plant in gardens, they suit natural gardens, landscaped or contemporary gardens alike.

Easy to grow, some loosestrifes can nevertheless become invasive. They develop a rhizomatous rootstock that spreads rapidly and is hard to remove. Indeed, Lysimachia punctata has become so well established in France that it is considered naturalized.

As for common loosestrife, Lysimachia vulgaris, very invasive, it has been declared invasive in some countries.

Botanical species of loosestrife

• Common loosestrife, great loosestrife or “chasse-bosse”, Lysimachia vulgaris

This botanical species is arguably most suitable for natural gardens and pond edges. Vigorous and fast-growing, it quickly colonises space, creates an attractive mass effect and stabilises pond banks. It bears bright yellow flowers on the upper third of its tall erect stems. Flowers are small and cup-shaped. Each flower measures only 2 cm across but flowering is long and abundant. This species is particularly invasive. When planting, it is advisable to use a rhizome barrier (thick, durable polypropylene film) to limit its spread.

• Lysimachia punctata

This robust perennial is recognised by its clusters of bright yellow flowers arranged in successive tiers. Undemanding, it tolerates all exposures provided soil remains fresh year-round. Like common loosestrife, this species produces many suckers in heavy, wet soils.

Our favourite varieties of Lysimachia

Lysimachia punctata Alexander - Loosestrife

Perennial and robust, Lysimachia punctata 'Alexander' has light green foliage variegated with pinkish-white.

• Flowering time August, September
• Height at maturity 70 cm

See the product sheet

Lysimachia clethroides - Loosestrife

This Chinese loosestrife, hardy beyond -15°C, is highly prized for its white flowers in curved spikes.

• Flowering time August, September
• Height at maturity 70 cm

See the product sheet

Lysimachia fortunei - Loosestrife

This robust perennial charms with its delicate upright white inflorescences above the foliage. Its foliage turns red-orange in autumn.

• Flowering time August, September
• Height at maturity 80 cm

See the product sheet

Lysimachia nummularia Goldilocks - Creeping Jenny

Lysimachia nummularia Goldilocks, also called moneywort, charms with its fine golden foliage. Spreading, it is ideal as groundcover both in ground and in a pot.

• Flowering time July to September
• Height at maturity 8 cm

See the product sheet

Lysimachia atropurpurea Beaujolais - Loosestrife

Lysimachia atropurpurea 'Beaujolais' stands out for its spikes of claret-coloured flowers. They appear above grey-green foliage that turns purple in autumn.

• Flowering time July, August
• Height at maturity 80 cm

See the product sheet

Planting Lysimachia

When to plant lysimachias?

Plant lysimachias preferably in autumn or spring. In autumn, plants have time to establish during winter: this period being wetter, it favours establishment of lysimachias.

Where to plant lysimachias?

Lysimachias prefer a sunny position although some varieties tolerate partial shade. They are suited to woodland edges, pond margins, damp meadows or a cool, sunny border.

They appreciate rich soil that stays fresh to moist. If ground is rather dry, lysimachias will be smaller and more compact. They tolerate humus-bearing to clayey soils, even heavy ones. They endure a neutral to slightly acidic or alkaline pH.

Hardy from -7°C to -25°C depending on variety, they can be planted almost anywhere in France.

They suit both contemporary gardens and natural or English-style gardens.

Planting lysimachias in open ground

Depending on the size of selected lysimachias, plant 3 to 5 plants per m².

1. For lysimachias in rootball, immerse rootballs while preparing the soil.
2. Dig a hole three times the size of the rootball or five times the size of the rootstock.
3. Some lysimachias can be invasive, especially at pond edges where moisture is constant year-round. To prevent this, fit a rootstock barrier.
4. If soil is poor, mix garden soil with 50% compost or potting compost.
5. Place the rootball level with the soil or set rootstocks at 25 cm depth.
6. Backfill with the soil mixture.
7. Water thoroughly.
8. Mulch around the plant to reduce watering and help keep soil cool for longer.

Water during the first years after planting.

Planting lysimachias in a pot

Since lysimachias like rich, cool to moist conditions, prepare a rich substrate that retains water well. For this, choose a potting compost for flowering plants to which you add a few handfuls of sand. In small proportion, sand helps water retention.

Choose a pot large enough so rootstocks can be set at 25 cm depth. Lysimachias grow quickly and will fill the pot.

During first years of establishment, water well. Then water only to keep soil consistently fresh to moist year-round. Soil must not dry out between waterings.

Planted in sun or partial shade, in rich, fresh to moist soil, the Chinese loosestrife is an easy plant that grows steadily.

Caring for your Lysimachia

Easy to grow, lysimachias require little maintenance and are not very susceptible to disease. They can be grown easily by beginner gardeners.

Lysimachia-atropurpurea-Beaujolais

At end of winter, cut back all dry stems of lysimachias to ground level if still present. New shoots for the year can then grow calmly. Slugs can attack young shoots — protect them from slugs. For more information: 7 effective ways to fight slugs naturally.

At onset of growth in spring, apply a surface layer of compost to feed your plant. For lysimachias with an upright habit, if stems seem too tall or not bushy enough, pinch them to reduce height and encourage branching of the stems.

As flowering progresses, remove faded flowers or cut spent stems back to ground level. This prevents the plant from using energy to produce seeds rather than to flower. By avoiding seed formation, you also prevent the plant from self-seeding and ending up with new plants all over your garden.

In summer, water and mulch around the base of your lysimachias to keep soil cool. Maintaining moisture is essential for good flowering. Mulching reduces need for watering. Soil should never dry out between waterings because lysimachias do not tolerate drought.

In winter, prune deciduous lysimachias back to ground level once they have lost all ornamental interest. This pruning is carried out between January and March.

To maintain vigour of your plant, divide the rootstock into several pieces every 5 to 6 years. For very vigorous specimens, contain the plant by removing invasive parts with a spade.

Caring for your lysimachia in a pot

To care for a lysimachia in a pot, provide the following additional care:

• Repot annually at start of spring using potting compost for flowering plants.
• From April until end of flowering, apply liquid fertiliser for flowering plants at each watering.
• Water so potting compost never completely dries out.
• Mulch the pot to retain moisture as long as possible and reduce watering.

Propagating your Lysimachia

Dividing Lysimachia

Although propagation by cuttings and sowing work to multiply Lysimachia, division has advantage of being faster and produces same variety as mother plant. Division is possible if mother plant is well developed. It is carried out in spring or autumn.

To divide Lysimachia, follow these steps.

1. Using a garden fork, completely lift Lysimachia rootstock.
2. With a spade, divide rootstock into several sections.
3. Plant each section about 25 cm deep in a hole five times wider than rootstock size.
4. Fill hole with garden soil mixed with 50% compost or potting compost.
5. Water thoroughly.
6. Mulch to retain soil moisture and limit watering.

Sowing Lysimachia

Sowing is possible but can be very long. Proceed as follows :

1. Sow on seed compost between February and July.
2. Keep compost moist with regular watering, cover with a plastic bag to maintain humidity. Temperature should be kept between 18°C and 25°C. Germination varies between 1 and 4 months.
3. When young plants are large enough for 8 cm pots, pot on into 8 cm pots.
4. Acclimatise young plants to outdoor conditions in partial shade when temperatures are mild.
5. Plant in sun or partial shade in rich, friable and moist soil.

Good to know: Lysimachia sold as seed are sometimes cultivars with short lifespan (1 to 2 years). They are grown almost like annuals.

Companion planting with Lysimachia

We often plant Lysimachia in partial shade to keep them consistently cool. Create a partial-shade border with Lysimachia; pair them with alchemillas, hostas, astilbes, Aruncus or ferns.

Pair Lysimachia punctata from front to back in the border: Astilbe simplicifolia Darwin’s Snow Sprite (first photo on the right), Hosta Paul’s Glory (second photo on the right), then the white spikes of Aruncus dioicus sylvestris (third photo on the right) and the purple foliage of Berberis thunbergii atropurpurea.

In sunny spots, Lysimachia blend well with rhubarb, angelica, Oriental poppies and foxgloves.

For pond margins, Lysimachia pair beautifully with moisture-loving plants: purple loosestrife, marshmallow, meadowsweet, filipendulas, candelabra primulas, horsetails, cranesbills such as the Geranium psilostemon or even a bush such as the Flamingo willow ‘Hakuro Nishiki’.

As for Lysimachia with a creeping habit such as Lysimachia nummularia ‘Goldilocks’, they make an ideal groundcover in a cool rockery or at pond edges. In a pot, create a graphic floral arrangement with annuals such as blue lobelias, mauve and violet petunias or the purple foliage of ipomoeas.

Golden, groundcover foliage of Lysimachia nummularia ‘Goldilocks’ with blue lobelia flowers (Lobelia Hot Royal Blue) and the purple foliage of Ipomoea Illusion Midnight.

→ Discover more ideas for pairing with Lysimachia in our advice sheet.

Did you know?

Lysimachias are also known for medicinal and dyeing purposes.

Common loosestrife, also called great loosestrife (Lysimachia vulgaris), is reputed for vulnerary and astringent properties. This earned it the name ‘chasse-bosse’. Yellow flowers of lysimachias are used to produce a yellow dye, while roots yield a brown dye.