Q. I am a Prince fanatic and in tribute to the legend I think some purple plants are in order. Foliage or flowers for a typical town garden, not very sunny, nasty London clay!
A. It sounds like some purple rain might come in very handy for your situation, but there are many plants available to create some flamboyance worthy of the artist.
And despite the obvious limitations posed by the town garden, the potential for a dazzling garden in keeping with the purple theme is mouth-watering.
Before getting going choosing your plants, which is of course the exciting bit, do everything you can to improve your soil conditions, adding lashings of organic matter and bucket loads of horticultural grit to counter the unfriendly texture and poor drainage offered by the clay.
Artistic licence kicks in immediately when referring to foliage colour in horticulture, as plenty of colours which are really bronzes, deep browns or reds are called or even named Purple.
On this basis, starting with structural shrubs you are allowed to include Cotinus “Royal Purple” a bit of a beast with dark leaves and terrific smokey flowers. Also one of the splendid Acer Palmatums such as “dissectum atropurpureum” or “Garnet”
For a strong architectural spikey contrast Phormium tenax purpureum has various sub varieties which include foliage on the blacker side of purple such as “Black Adder”, “Black Velvet” and even “Black Rage” very tempestuous and with a strong contemporary flavour.
Not so dramatic, but useful as a mid-height evergreen shrub is Hebe Mrs Winder whose foliage qualifies on the bronze cheat basis but which also has purplish spikey flowers.
In the herbaceous category of purple foliage there are numerous choices for our vegetative soundtrack. Persicaria “Red Dragon” has red stalks but very striking purple leaves. The genus Heuchera which is being bred in more shades than a Farrow and Ball colour chart , will provide powerful purples such as “Palace Purple”, “Plum Pudding” and even “Purple Rain Forest” (hey!). Sedum Purple Emperor has succulent clusters of dark purple leaves with a pinky flower in September which contrasts nicely with the foliage.
Purple is very kind to yellow and another great purple foliage plant which looks even better when in flower is Lysichmachia ciliata Firecracker. Significantly more striking than yellow flowers with green leaves which occur on plain ciliata.
And now purple flowers, which will suit our Paisley Park.
In the most open and sunny section of the garden plant some of the stunning giant ornamental onions such as Allium Globemaster or Allium Purple Sensation.
Less demanding of sun is the very useful late flowering Liriope muscari which has hyacinth like flowers in the autumn and forms good clumps, growing well almost anywhere.
And to cover the late winter and early spring there are some superb hellebores which should be in any garden, not just this one. Try Helleborus Double Ellen Purple or Helleborus Harvington Shades of Night. Both shade tolerant.
The final suggestion is one I haven’t grown but which surely must be found a place. It’s a purple leaved ornamental fountain grass; Pennisetum purpureum ‘Prince’