How to grow: French honeysuckle. By Carol Klein.

How to grow: French honeysuckle - Telegraph
'Once seen, never forgotten', writes Carol Klein
Imagine a whopping clover with flowers of brightest red borne on strong stems that form an open bush 3ft high. For good measure add glaucous pinnate leaves, silver rimmed and silver on their reverse. Hedysarum coronarium is a once seen, never-forgotten sort of a plant. It is instantly attractive and has huge presence in any planting scheme.
Pinks abound, crimson is common but a good clear red is a rarity in the garden, which is part of its draw. Another is the heightened magnetism of this colour when surrounded by foliage. The eye is unused to seeing red and green of the same tone next to one another: the discord makes us see stars.
The Linnean herbarium lists more than 30 hedysarum but most are vetch-like plants of lowly demeanour and none can compare with H. coronarium. This is a legume, closely related to peas and beans.

The roots fix nitrogen in the soil and the foliage is full of nutrients, which is why in parts of Italy it is grown specifically for cattle feed - a field of hedysarum in full flower must be a breathtaking sight.
One of its common names is French honeysuckle; the sweetly scented flowers are rich in nectar, making it a very important crop in honey production.
It is often treated as an annual when grown agriculturally. In gardens it will last for several years given the sort of conditions it needs - full sun and soil that does not dry out.
Its native haunts are damp grasslands from the western Mediterranean through to Sicily. There it may start to flower as early as March, peaking in May, which is when it starts here.
Each strong branch throws out lateral shoots that often branch again, the tips bearing cylindrical clusters of flowers. The first will be in seed as the last are budding up. As the flowers age the colour fades slightly, lessening the impact, but there is a constant succession of new red-as-red-could-be blooms often until late summer.
How to grow
Like most peas and beans hedysarum is happiest on alkaline soil but it is not averse to neutral or even slightly acid conditions. Add calcified seaweed or a dressing of lime before planting. Avoid nitrogenous feed, including muck, which would result in floppy growth and fewer flowers.
In a shadier site, even next to tall perennials, it can become gangly and lose its self-supporting reputation so always plant it in an open position without too much competition.
Growing from seed is the only way to make more. Unusually, it doesn't produce capsules or pods. Each seed is supported by the next in a column. They are large and can be handled individually. Best practice is to sow separately in modules or cell trays, potting on when roots start to protrude.
Plants from a summer or autumn sowing can be over-wintered in a cold frame or greenhouse. From an early spring sowing, they should be ready to take their permanent positions in late summer after a period of aclimatisation.
Good companions
Silvery shrubs make the perfect backdrop, picking up the lining of the hedysarum foliage. Elaeagnus 'Quicksilver' is ideal to create a hot, summery feel. The silver filigree of Artemisia 'Powis Castle' forms soft clouds to billow around the hedysarum's skirts.
To emphasise the brilliance of the red flowers surround it with green. Some of the bigger molinia are ideal and are still relatively low as the hedysarum starts to flower. Crocosmia foliage with flowers yet to come or Euphorbia palustris with flowers already finished make a verdant foil.
For a red and green planting combine it with Potentilla atrosanguinea. The silvery reverse of its pleated, tri-foliate leaves echoes the silvery edges of the hedysarum foliage.
Where to buy
Arn Hill Plants, 62 West Lockinge, Wantage, Oxfordshire OX12 8QE (01235 834312; www.arnhillplants.com). Mail order available - catalogue free. Open by appointment.
Arne Herbs, Limeburn Nurseries, Limeburn Hill, Chew Magna, Bristol BS40 8QW (01275 333399; www.arneherbs.co.uk).Mail order available - please send £3.75 for catalogue, refundable on first order. Open Monday to Friday 10am-4pm, but call to check first.
Glebe Cottage Plants, Pixie Lane, Warkleigh, Umberleigh, Devon EX37 9DH (01769 540554 ). Seeds also available. No mail order - please send £2 for a catalogue. Open Wednesday to Friday 10am-1pm and 2am-5pm.

- FRENCH HONEYSUCKLE SEEDS - HEDYSARUM CORONARIUM | Hardy Annual Flowers