Common name: Purple Loosestrife
Purple loosestrife is native to Europe and Asia.
This hardy upright, semi-woody, bushy herbaceous perennial and is extremely adaptable to a wide range of conditions, and will grow almost anywhere except in full shade.
This characteristic makes them a useful subject for the borders of water features.
They grow to around 600-750mm (24"-30") high, and their purple to magenta on long spikes flower from late June until October.
They can be a very invasive plant, in fact they can be so invasive to the point that they can be considered a weed in some areas.
For this reason deadhead regulary to keep it from self seeding.
Sow in pots / trays of seed compost and germinate at a temperature of 16°C (60°F)
Named varieties do not come true from seed.
Prick out the seedlings when large enough to handle in 75mm (3") pots of potting compost and grow on in a coldframe until planting out time.
Take 75mm (3") long basal cuttings, and insert in pots of 50-50 in equal parts (by volume) peat and sand.
Place in a coldframe to root in a cold frame.
When rooted, treat as seedlings.
Plant out 500mm (18") apart in ordinary garden soil in sun or semi-shade.
These plants will thrive near water, in a damp / wet semi-shaded situation.
Cut back plants to ground level.
Plants can also be divided at this time.