Swiss Chard comes in many colours - try a packet of mixed seed.
It is normally overlooked that many vegetables have either colourful flowers, stems or foliage. They are well suited to ornamental use and as such, suitable for planting and integrating into the normal ornamental areas - including shrub borders, and flower beds.
Shrub borders ten to remain a little on the dry side, so any vegetable planted there would not normally be used for food. Exceptions there are - such as ornamental sages, Thymes, and Marjoram. herbs maybe, but a normal part of the wider picture of vegetable growing.
Swiss Chard has to be high on the list of ornamental vegetables, with its brightly coloured stems, and from the same family - the common beetroot with the red foliage - and spectacular seed stalks if you leave them! They look gorgeous in the ornamental border with the bright splash of colourful stems.
For Silver grey, nothing can compare with the Cardoons - at home in the vegetable plot or the flower bed - or in particular the Herbaceous Perennial border.
Lettuce are increasingly available as feathery frilly leaved and multi-coloured varieties. They may look great in a salad, but they also look spectacular in the flower bed - or grown in Patio Containers where they are easty to crop.
For a bit of height, try a few runner beans up a trellis, net or
one of the more ornate obelisks that are now available. Flower
white, red or bi-colour - and quick growing.