Sweet Pea Parfume Millennium

Deep velvet crimson that shimmers like ruby silk, frequently four flowers to a stem, on a vigorous climber to 2.4m. It holds an RHS Award of Garden Merit.

The problem with crimson sweet peas is that they burn. A hot spell in July scorches the petals brown at the edges and washes the colour out, and it is the commonest complaint about red varieties. 'Millennium' was selected for colour stability and holds its crimson from opening to fading regardless of the weather, which is why it turns up on the show bench so often.

One note on sowing that applies to every sweet pea and catches people out. Keep them cool. Sweet pea seed germinates best at around 15°C, and high heat causes outright germination failure, so a warm propagator or an airing cupboard is exactly the wrong place for them.

Give it rich ground with plenty of manure dug in, a proper support, and pick every flower as it opens, because a plant that sets seed stops flowering.