Penstemon ‘Swan Lake’

Penstemon 'Swan Lake' (Penstemon 'Swan Lake') is the white flowering perennial to plant when a border needs height and a long season rather than one big show. It makes an upright clump about 80cm tall and 50cm across, sending up spires of tubular white flowers from late spring well into autumn. Frost hardy, drought tolerant once established and heat tolerant, it is unusually tough for a perennial this refined.

Why you'll love it

• Months of flowering. Successive spikes carry from late spring into autumn, so it earns its space for most of the year.
• White that works with everything. Pure white tubular flowers lift dark foliage, cool down hot colour schemes and glow at dusk.
• Tough once established. Frost hardy, heat tolerant and drought tolerant, so it holds up through a dry summer without constant attention.
• Bees, butterflies and birds. The tubular flowers are built for nectar feeders, which brings pollinators and small birds into the bed.
• Vertical structure at a low height. At 80cm it adds movement and lift without blocking the view over a border.

Where it works best

Borders and edging. Plant 40cm apart for a full border. At that spacing the clumps meet, support each other in wind and read as a continuous drift rather than separate plants.

Mass planting. Use the same 40cm spacing across a larger bed. Groups of five or seven look far better than a single row, and the flowering spikes give a bed real presence in summer.

Pots and feature planting. One clump in a 400mm pot makes a good courtyard subject, taking full sun on a paved terrace without sulking.

Growing Penstemon Swan Lake in Australia

Position and climate. Full sun gives the most flowers and the sturdiest stems. This is a plant for warm temperate, cool temperate and Mediterranean gardens, which covers most of southern Australia. It is not suited to the wet tropics or humid subtropical summers, where the crown tends to rot.

Soil. Drainage matters far more than fertility. Free draining soil is essential, so on heavy clay raise the bed or plant on a mound and work in coarse compost. Wet winter feet are the usual cause of losses.

Water and feed. Water regularly through the first summer, then only in extended dry spells. A light application of complete fertiliser in early spring is enough, since rich feeding produces soft growth and fewer flowers.

Pruning. Remove spent spikes through the season to keep new ones coming, then cut the whole clump back by about a third after flowering to keep it compact. Divide congested clumps every three or four years.

What to expect when it arrives

This one is sold as tube stock, which is the practical way to buy a perennial you plan to plant in numbers. Tubes are young plants with a small crown and a few sets of leaves, and they establish fast: expect a filled clump in one season and a proper flowering display in the second.

Soft perennial growth can look a little tired after transit, which is normal. Plant it out promptly, water it in well and it recovers within a fortnight. Delivered Australia wide, with delivery from $29.95. Every plant carries our 30 day healthy plant guarantee.

Plant care guides and related reading

• Read our guide to perennials for a cottage garden.
• Browse plants that attract bees and butterflies.
• Compare other drought tolerant plants.
• See more low growing border ideas.

Common questions

How far apart should I plant it?

Space the clumps at 40cm centres. Each clump reaches about 50cm across, so that spacing closes the gaps within a season while the stems still get air movement.

Will it survive frost?

Yes. It is frost hardy and suits cool temperate gardens, dying back somewhat in a cold winter and reshooting in spring. Good drainage matters more than temperature.

Why has mine stopped flowering?

Usually spent spikes left on the plant, too much shade or over feeding. Cut finished spikes off as they go over, keep it in full sun and feed lightly.