Loosestrifes range from ground covers to upright perennials. Many make good cut flowers. Most types have clusters of yellow or white flowers arranged in tall spikes.
- Common name: Loosestrife
- Botanical name: Lysimachia spp.
- Zones: 3 to 9, depending on species
- Height: To 4 feet tall, depending on species
- From: Areas of Europe, Asia, and North America
- Family: Primulaceae (primrose family)
- Sun: Full sun or partial shade
- Soil: Moist, well-drained soils are best, but the plants adapt to many types of moist soil.
- Moisture: Keep soil evenly moist.
- Mulch: A layer of mulch around the base of the plant will help keep weeds at bay. Mulch also helps conserve moisture and keeps soil temperatures consistent.
- Pruning: Cut plants back in autumn after they freeze or in spring before they begin to grow.
- Fertiliser: In average soil, no fertiliser is necessary.
- Division: Divide loosestrifes in spring or autumn.
- Leaf spot: In summer or autumn, leaves develop yellow to brown spots, often with concentric rings that form a bull’s-eye pattern. To deter leaf spot, prune the plant to allow good airflow and avoid wetting the foliage in afternoons and evenings.
- While not aggressive weeds, some loosestrifes can grow quickly in the garden. Root guards may help prevent spreading; leave some space between loosestrifes and plants that don’t grow as quickly.
- Don’t confuse these loosestrifes (Lysimachia spp.) with the invasive purple loosestrife (Lythrum spp.).
- Lysimachia ciliata: Grows to 4 feet tall with yellow flowers in summer. This species can get quite aggressive. Zones 3 to 9. Native to areas of North America.
- Lysimachia clethroides: Grows to 3 feet tall with spikes of white flowers in summer. This species can get quite aggressive. Good for cutting. Zones 4 to 9.
- Lysimachia clethroides ‘Geisha’: Grows to 3 feet tall with leaves edged in creamy yellow and spikes of summer-blooming white flowers. Grows much slower than the species. Good for cutting. Zones 4 to 9.
- Lysimachia nummularia: Aggressive ground cover with yellow flowers in summer. Grows to 4 inches tall. Zones 4 to 8.
- Lysimachia punctata: Grows to 3 feet tall with spikes of yellow flowers in summer. This species can get quite aggressive. Zones 3 to 9.
- Lysimachia punctata ‘Alexander’: This selection grows to 3 feet tall with leaves edged in white and spikes of summer-blooming yellow flowers. Grows slower than the species. Zones 3 to 9.