Gardeners: grow up for God’s sake!
How many gardens do you see that are basically 2D? There may be a tree or shoulder-high shrub in one corner, but the rest – lawn, bedding and edging, are rarely more than a foot high.
Look at any natural ecosystem and there are plants evolved to fit in every niche and height. They don’t grow in order of size.
People are OK with using tall plants as long as they’re up walls or at the back of borders, but there’s a fear of putting them ‘in front’ of anything.
Free-standing vertical elements in a border – tall, slim annuals or perennials, climbers grown on canes or obelisks or suitable shrubs or trees – break up your perception.
Your eyes rest on this “high point”. One of the first rules of garden design is don’t left everything be seen in one glance. You’re forced to look around these ‘false corners’ to discover what comes next.
Here are some of my favourites:
Sunflower (Helianthus): the sky’s the limit if you grow annual Mongolian Giant or Giraffe (14ft)! These are novelties – opt for one of the multi-headed six-footers that don’t need staking, such as Helios Flame or Bees’ Knees.
Perennial Helianthus: Lemon Queen is the best, late flowering, with dark foliage up to 6ft.
Sweet peas: trained up an obelisk at the front of the border, can make a great impact. Try Cupani, Fragrantissima or Old Spice for the best perfume.
Perennial sweet peas (Lathyrus latifolius): will grow 8ft from the ground each year. It’s as tough as old boots – I’ve come to terms with one wedged in a crack in a wall I can’t kill, so now I work with it. Some years I use it as ground cover, others trained up an obelisk.
Echium: I have a ridiculous passion for this genus, not our native viper’s bugloss (shame on me), but the exotic type from the Canaries, ever since I grew a mixed pack of E. pininana. They’re either bi- or triennial, depending on conditions. Some can have 12ft flower spikes, but mine were restricted in pots to just 4-5ft. I also grow E. wildpretii, E. fatuosum, E. fatuosum Dwarf Blue and E. Red Rocket. Beware slight irritation to some from long, pointy leaves.
The giant mullein, Verbascum bombyciferum: a silvery, woolly rosette of leaves, 3ft across, which gives way to a yellow candlestick of blooms, 6-7ft high. It’s a biennial but seeds itself around freely.
Angelica and purple angelica (A. archangelica and gigas): both will tolerate some shade. They are biennials too and their ornamental leaves are boosted by huge umbellifer flower heads.
Verbena bonariensis: a favourite of designers, it always dies on me. Long, wavy strands of purple flowers form a living mesh to view other things through.
Stipa gigantea: with its 8ft stems are a favourite, very architectural for winter interest – like a giant net curtain.
Productive crops: runner beans are ideal over cane wigwams. The thornless blackberry Loch Maree can be grown this way, with its double pale pink flowers, autumn fruit and winter leaf/stem colour.
Foxgloves: British natives are not that tall, but hunt out some of the rarer varieties, especially in mixed packs of seeds, and you’ll find some whoppers. The sad fact is, the taller they are, the shorter their lives and vice-versa – the shortest tend to be perennial in my experience.
Teasel (Dipsacus): A wildflower favourite with spiny pink/purple flower heads rising out of a prickly rosette of leaves in summer. These heads dry to an attractive shade of brown, much-loved by birds and flower arrangers. Teasels are biennials but self-seed freely. About 6ft and will stand some shade
Cardoon (Cynara) and globe artichokes: Very similar and edible, but I prefer them in a border for their huge thistle-like flowers and striking seed heads which stay on over winter.
Kniphofia (red-hot pokers): Striking late summer colour from the exotic-looking strap-like clump and hardier than they look.
Clematis alpina, climbing roses, or fast-growing exotic annual climbers grown over obelisks: Any old climbers really – but avoid any with spines if growing near a path – or the golden hop – it can cause skin irritation.