SONG THRUSHES in my garden sing - one could almost say shout - a message of spring, but the lawns and borders are still white with frost in the mornings. Warm days still seem an eternity away.

Over the years I have collected a number of plants from places in Britain and on the Continent. These have sentimental associations - soapwort from seed gathered from a roadside clump in Suffolk, wild orpine from a local wood ruined by a timber company, a spurge laurel rescued from a building site at Coggeshall.

Yesterday I looked at my surviving plant of the 'Mersea Pea' in a frost-whitened border near my front door.

Some years ago I gathered some seed of this attractive alien plant which was growing at the edge of the carpark at the end of Fairview Avenue [sic. Fairhaven] and on rough ground nearby.

No-one seems to know how the plant got there in the first place. Its scientific name is Tetragonolobus maritimus (formerly Lotus siliquosus), and it is commonly found in southern Europe and Mediterranean countries, although patches are encountered as far north as the Pas de Calais.

The English name given to this sprawling , hairy and grey-green perennial is Dragon's Teeth, although to local botanists it will always be known as the Mersea Pea.

It is naturalised in a few grassy places in south east England. My own view is that it is an "escape' from gardens.

The "Mersea Pea", a southern European and Alpine plant naturalised on Mersea Island and a few other places in south east England.

LISTED

Looking through my Thompson and Morgan catalogue the other evening (what a mine of information that 130-page compilation is) I came across maritimus in the seed list.

The Mersea Pea, for that's what I'll continue to call it, has large, broad leaves like those of the common birdsfoot trefoil, but its flowers are solitary, an inch long, and a beautiful pale yellow. The standard and calyx tube are red-veined.

Seed pods of the Mersea Pea are two inches or more long, four angled, and dark brown when ripe.

About twelve years ago I found a big patch with an abundance of seed pods and gathered several, putting them in an envelope when I got home, stowing them away in a sideboard drawer.

Inevitably I forgot all about the seed until two years ago when I was having massive spring clean.

Suspecting that at least a few of the little pea seeds would still be viable, I asked my father to sow them in a pot in his greenhouse.

I was delighted when he produced the pot some months later full of sturdy plants. These were planted out in a border where they flourished and seeded.

During reorganisation in the garden all but one of the plants were destroyed, but the survivor not only grows larger annually; last summer it flowered profusely and seeded, so I hope to raise and plant a group later this year.

When I was botanising and butterflying in the hot Basses-Alpes region of Provence last summer I found the Mersea Pea to be an abundant plant on the limestone mountains and beside the roads.

Although these specimens were of a glorious lemon yellow colour, they were smaller than the Essex flowers, probably because they were sun-shrivelled and unable to find much moisture during the long, hot Provencal summer.

Mr Stanley Jermyn, of Felsted, who is writing the new Essex flora, told me this week that the Mersea Pea was first reported in the car park, now asphalted over, in 1930 and was subsequently discovered in rough grassy ground nearby, where it still occurs.

It is also found in gardens, where owners are preserving it, and at the edge of the putting green.

Mr Jermyn said the plant was also discovered by the late Capt Sparrow at Pulpits Farm, Hockley in 1935 and it is still thriving there.

He considers the plant was an accidental introduction, rather than a garden escape.

There is another member of the Tetragonolobus family (purpurea) which is known as the asparagus pea. This plant has pretty red flowers followed by curious rectangular, flanged pods.

These pods are edible and are harvested when about an inch long. When cooked whole they have a subtle flavour, a bit like that of asparagus, hence the name.

Personally I have found the pods somewhat stringy, but this is probably because I have not picked them young enough.

I grow purpurea in my garden, not for its culinary qualities but because I find it a most attractive plant in its own right.

The red pea flowers and luxuriant leguminous foliage can provide an unusual display in a garden corner.

Once again the Ipswich firm of Thompson and Morgan have this plant in their seed catalogue, featuring it in the vegetable section.

I noticed considerable activity in the heronry on the south side of Abberton Reservoir last weekend.

The big nests showed up boldly in bare elms and almost every one had a heron standing on or beside it, a sure sign of impending breeding activity.

Thank goodness these elms have been spared when so many trees and hedges in the vicinity have been destroyed. All naturalists will thank the farmer concerned for his interest.

The 60 white-fronted geese, which I reported in last week's column, were still present at Abberton Reservoir on Sunday.

They were swimming at the far end of the reservoir, on the Layer Breton side, watched by enthusiasts though every type of binocular and telescope.

Joe Firmin

One of the sites where the"Mersea Pea" is still found is round the edge of the putting green between Victoria Esplanade and the beach.