This isn’t a blog about drought tolerant planting (that’s another one) but some suggestions for planting, particularly architectural plants, that will be quite happy if you ignore except to simply admire it.
I was considering the idea from a ‘going on your summer holiday’ perspective, but the plants are easy maintenance once established so would of course be happy in your garden at all times of the year.
Most established planting, both shrubs and herbaceous perennials, should be fine without watering by you, whether you’re at home or away. This does assume that the soil is good and that the plants have been chosen correctly, shade lovers in a sunny border are not going to be happy, for example.
The term architectural plants generally describes tall, statuesque plants often seen in very contemporary gardens, although it also includes ornamental grasses, Phormiums and bamboos. People are often put off from choosing some of these plants, concerned that they may not fit into a mixed border, or might be too big for their garden. Generally speaking though, adding a ‘wow’ plant can really lift a border, giving it a new lease of life.
What are Architectural Plants?
Architectural plants may be herbaceous perennials, annuals and shrubs as well as ornamental grasses and bamboos, and it is herbaceous perennials that I’ll be suggesting as if it’s your first foray into architectural plants you may feel reassured by the domestic familiarity of plants which die back over winter and shoot up in the summer.
The plants will work as part of cottage style planting, minimalist and contemporary gardens, and also many historically inspired schemes (the Victorians in particular were great Plant hunters and introduced quantities of species to Britain). They’ll also be useful in potager and ornamental kitchen gardens as pollinating insects and predator insects will be encouraged in by their flowers.
Architectural Plants – Foliage
Persicaria
Persicaria are members of the knotweed or Polygonaceae family, but are now often referred to as smartweeds, rather than knotweeds to distinguish them from their invasive cousins. 
Persicaria like a moist or damp soil and will tolerate shade partial shade and sun, but this latter with moist soil, or it will droop and look unhappy. There are a range of varieties to choose from, with the dark pink flowered Persicaria ‘firetail’, the bronze leaved Persicaria microcephala ‘red dragon’, and the edible Vietnamese coriander, Persicaria odorata.
Acanthus mollis
Acanthus mollis, ‘bear’s breeches’ is a wonderfully architectural herbaceous perennial that is drought tolerant, so will not notice if you’re away on your holidays and haven’t watered it. What Acanthus is not so keen on though, is being under the shade of evergreen trees, where it has to fight for its water and nutrients; it grows to a large plant and doesn’t do so well with competition.
However, it will cope with being grown against a wall, so long as the soil is humus rich at root level. With its glossy green leaves and tall flower spikes Acanthus mollis suits both modern and cottage garden planting. Acanthus spinosus has similar leaves but with a spine at the tip – hence ‘spinosus’.
Architectural Plants – Height
Giant scabious
Giant scabious (Cephalaria gigantea) is a plant that is happy in the Isle of Skye, Cornwall, Greater London and all gardens in between. This is a mature clump, about eight foot high; initially you’ll get the height without the bulk, with the flowers reaching five foot in their first year.
With large heavily dissected foliage and soft yellow flowers that are fascinating from bud stage to seed head this plant has to be a winner. Bees and pollinating insects also adore the flowers, whilst birds enjoy the seed heads.
The flowers are carried on long stems and may need staking in very dry conditions, so if you’re growing it against a wall or fence where it may not benefit from rainfall, be sure to dig in lots of organic matter into the soil when first planting.
Teasel
Teasel (Dipsacus sylvestris) is a British native species. I’ve cheated a bit as this is a bi-ennial not herbaceous perennial, but once established by sowing seed two years running you will have plants every year. As with the Giant Scabious, Teasels are a popular feeding plant for wildlife.
The skeleton of the seed heads often last right through to the following spring, although the birds will have eaten the seed off well before then. One lovely feature of these plants is the way rain water collects in the cup like depression of the leaf where it meets the stem. Both stem and leaves are covered with prickles, so it’s a good idea not to plant too near a path or seating area.
When established, Giant Scabious and Teasel both have a tendency to self seed with enthusiasm but the seedlings are easily recognisable and simply removed by hand or with a dandelion trowel.
Hopefully this selection has given you some inspiration for adding a different type of plant to your garden – an architectural plant which once established you can wave goodbye to when you venture on your summer holiday, knowing it will be quite happy while you’re away.
Related Gardening articles you may enjoy from our Award Winning Blog
Midsummer Gardens
Summer Gardens – Questions and Answers
Turquoise Birds and Turquoise Flowers
