One of the first plants we bought for our Pennsylvania garden, years ago now, was a hardy Chinese Impatiens species called Impatiens omeiana. It's a hardy perennial related to the colorful Impatiens seen in containers around the world. As you can see (above, click to enlarge), in summer it features these beautifully marked leaves and now we’re seeing clusters of yellow flowers in the tips of the shoots (blow, click to enlarge).

We’re in US hardiness zone 5 (-29C/-20F) which is off the cold end of the scale of the new British hardiness ratings system launched earlier this year by the RHS. The winters certainly get chilly and occasionally our Chinese Impatiens has taken a hard knock. Some years, in spring, just a few spindly shoots emerge but by summer those few stems are looking luxuriant and the following year there’s again a fat clump. This year, we have a couple of interesting perennials underneath, Hosta ‘Maui Buttercups’ and Brunnera ‘Silver Heart’.

Hosta ‘Maui Buttercups’ is one of the best yellow-leaved hostas and it’s also small, not much more than 25cm/10in in height – it’s a classic “sunshine in a shady place” plant and its coloring connects with the stripe in the Impatiens leaf and with its yellow flowers. A cross between two old favorites, 'Frances Williams' and 'August Moon’, the off-white flowers are, frankly, a distraction; I’d snip them off. This is a plant that suffered in our vole infestation but is now thriving again.

Also tucked under there is the brand new Brunnera ‘Silver Heart’ which is a new improved form of ‘Looking Glass’ with very heavy duty foliage and a brighter silver sheen – it really gleams.

The foliage shape of both these perennials contrasts attractively with the slender Impatiens leaves, and all are happy shaded from the east, and from the west late in the day.

Farther back, the leaves of a climber in a different shape have made their way over from a pot a few feet away. It’s a climber that goes by a rather heavy-handed name – Ampelopsis brevipedunculata var. maximowiczii ‘Elegans’ (left, click to enlarge), or is sometimes known as the variegated porcelain vine. As well as these very pretty variegated leaves, clusters of porcelain blue berries mature in the fall. The green-leaved version of this plant is invasive in some parts of North America, but here this variegated form has never produced a seedling.

But these four plants have made an appealing plant picture for months – and they’re still going strong at the end of September.

North American gardeners
You can order Impatiens omeiana from Burpee
You can order Hosta ‘Maui Buttercups’ from The Hosta Farm
You can order Brunnera ‘Silver Heart’ from Romence Gardens
You can order Ampelopsis brevipedunculata var. maximowiczii ‘Elegans’ from Digging Dog Nursery (though it may be considered invasive in some parts of North America)

British gardeners
You can order Impatiens omeiana from these RHS PlantFinder nurseries
You can order Hosta ‘Maui Buttercups’ from Mickfield Hostas
You can order Brunnera ‘Silver Heart’ from Coblands Nurseries
You can order Ampelopsis brevipedunculata var. maximowiczii ‘Elegans’ from these RHS PlantFinder Nurseries