When designing a planting scheme, it’s easy to be seduced by glossy mags offering new varieties.

Hundreds of plants are launched each year, with big claims of hardiness, longevity and a free-flowering nature… but many don’t cut the mustard.

I prefer my list of tried and trusted stalwarts that I know won’t let me down. Mine have to be strong, reliable, disease resistant and interesting for more than just a few weeks. At this time of the year, gardeners are thinking of brightening up their borders.

Here are some of my favourite flowering perennials.

• Verbena bonariensis, with its purple flowers and see-through quality, can be as effective at the front of the border as the back, making it easy to dot into a planting scheme. It provides vertical interest, vibrant colour, and its tall, sturdy stems can even prop up floppier plants.
• Hardy Geraniums, not to be confused with pelargoniums sold as summer bedding plants, are useful for lush, often aromatic, ground cover. They are easy to grow; there’s one for every garden situation. Bursting with bright blue flowers, Geranium Rozanne is one of the most readily available varieties. It blooms June-October, in sun or shade, and spreads quickly, so needs space. Looks great under shrub roses or tumbling over a wall. Geranium White-Ness is undemanding and thrives in any situation – its pure white flowers are useful for brightening up a dull, shady area. Geranium Patricia is one of the taller varieties. It has vivid magenta flowers and is perfect for the middle of the border.
• Salvia Viola Klose, pictured, has distinctly dark stained stems and provides neat clumps of deep purple flower spikes which bloom from June-September. Salvias come in all shapes and sizes, from common sage to summer bedding salvias in a range of garish colours. But Salvia Viola Klose is different. Close cousins Salvia Mainacht and Salvia nemorosa Caradonna are just as good.

All feature at the Hampton Court Flower Show, July 2-7. For info, visit www.rhs.org.uk

Janice Cripps is a professional Surbiton garden designer. For advice, planting plans, or projects – from concept to completion – visit www.janicecripps.co.uk