Perennials and tender plants for gorgeous seasonal container displays

As the risk of frost is finally behind us, it is safe to start planting out half-hardy favourites such as pelargoniums, fuchsias and succulents. These tender plants can now move from the protection of a frost-free greenhouse into their summer containers without fear of cold damage.

Last week, the garden team refreshed our two main seasonal pot displays. At the entrance of our Visitor Information Centre containers are filled with sun-loving species that relish heat and intense light, perfectly suited to the bright, open, full-sun conditions of the Gravel Garden.

By contrast, the display on Beth’s patio, sheltered beneath the canopy of a mature Magnolia soulangiana, calls for a more nuanced approach: a blend of shade-tolerant plants, including perennials and ferns. Fuchsias do well here, complemented by a handfull of other half-hardies that enjoy occasional pockets of sun.

Over winter, the pots are filled with a mix of evergreen perennials and spring-flowering bulbs, keeping the display attractive throughout the colder months. Now that the bulbs have finished flowering, they’ve been lifted from the pots and rehomed in the garden, where they’ll return year after year. This frees up the space needed to create a fresh, vibrant summer display that will last until autumn.

Beth’s pelargonium collection has gradually evolved into a beautiful assortment of distinct leaf textures, shapes and wonderfully fragrant varieties. Emily is now continuing the tradition – collecting, propagating and growing these special plants.

We are delighted to offer a limited selection of pelargoniums and succulents at the nursery, with a small number also available online. Availability is first come, first serve.

Many perennials, ferns and ornamental grasses make excellent choices for container displays. While most half-hardies are a recurring yearly expense - unless you can overwinter them in a frost-free greenhouse as we do - perennials are a long-term investment: buy once, enjoy them their return year after year, and benefit from the ability to divide or take cuttings for seasons to come.

For pot displays, almost any container will work as long as it has adequate drainage holes. We always place a few broken terracotta pieces at the base of each pot; these shards cover the hole preventing the potting compost from escaping without blocking the drainage.

We make our own compost mix for the containers using a peat-free base, blending in horticultural sand to improve drainage at a rate of two-thirds compost and one-third sand.

When it comes to planting the possibilities are endless.  You can keep things simple by giving each pot a single type of plant - great way to highlight contrasting leaf shapes, colours and textures. Or for a richer, layered look, combine a few different varieties in one container to create a miniature garden with depth and character.

Half the joy of container gardening comes from experimenting – mixing, matching and discovering which combinations thrive. Just be sure the plants you group together share similar light, water and nutrient needs, so the whole arrangement grows happily as one.

Whether you plant a single specimens in each container or mix several varieties together, the same design principles you’d use in the garden still apply. Combine contrasting textures, shapes and forms. Include a plant that provides height, one that creates a rounded mound, fillers that can weave among their companions, and something that elegantly spills over the rim of the pot.

Here are some of our favourite perennials for container displays:

The flat-topped blooms of Achillea ‘Terracotta’ and other cultivars pair beautifully with hardy geraniums, wispy grasses, spiky blue eryngium and the upright spires of Salvia nemorosa.

Diascia barbarae ‘Blackthorn Apricot’ produces a mass of soft apricot flowers throughout summer, especially if deadheaded regularly.

Knautia macedonica offers freely branching stems topped with crimson pin-cushion flowers that attract pollinators.

Nepeta ‘Hill Ground’ a lovely catmint selection with bushy growth and intense violet-blue flowers, while Nepeta racemosa ‘Amelia’ forms a neat mound of pale pink blooms above grey-green foliage

For shade, it’s hard to beat the large, silver-marbled leaves of Brunnera macrophylla ‘Alexander’s Great’.

Fuchsia ‘Hawkshead’ brings a quiet, understated charm – far removed from the more flamboyant, colourful fuchsias – with slender white flowers tipped in green as though lightly dipped in paint. Together, they brighten a dark corner where it pairs well with ferns, Liriope muscari, hostas and hakonechloa.

The dusky cranesbill, Geranium phaeum - in some cultivars its leaves are marked with an attractive dark blotch - tolerates sun provided the soil doesn’t dry out, but truly thrives in dappled shade. Cut back after flowering to encourage a second flush of fresh foliage and the occasional bloom. G. phaeum ‘Robin’s Angel Eyes’ is especially lovely, its purple flowers fading to towards the centre with a soft halo at the base.

For troughs and small containers in full sun, house leeks, sempervivum, are among the toughest of plants. Creeping thyme such as Thymus ‘Bressingham’ thrive in broad, shallow vessels that suited to their spreading habit. For a touch of delicacy Origanum ‘Dingle Fairy’  brings dainty pink and apple green bracts that last for weeks and small lilac-pink flowers, perfect for a rock-garden style planting. Or let it spill over the edge of a terracotta pot.

To soften edges, Erigeron karvinskianus, or the pale lilac form E. karvinskianus ‘Lavender Lady’ will form a neat, soft cushion.

The succulent, dark foliage of Delosperma Desert Dancers ‘Purple’ forms a low mat, only about 10cm heigh – topped with vivid neon pink flowers. It pairs beautifully with low-growing sedums in succulent arrangements.

For a foliage accent, the Dwarf Lady’s mantle Alchemilla erythropoda is ideal for small containers. This species is equally happy in full sun, where the leaves often take on a subtle reddish tint, or part shade, making it a versatile companion in mixed plantings.

Container plants require more regular feeding than those in the ground. The garden team have prepared nettle tea which will be ready in a few weeks. They cut and crushed nettles (treading on them to break them down), then submerged them in water inside a bin covered by a lid. Once fermented, the feed will be diluted at a ratio of 1 part nettle tea to 9 parts water before use.

A word on watering 

Different plants have different watering needs, so it’s essential to understand what each one requires. Water only when necessary, rather than out of routine. Always direct water to the base of the plant, at soil level, where the water can be absorbed. Adding a mulch layer – such as gravel or crushed bark - helps reduce evaporation.

If watering in the evening, take extra care to keep the foliage dry to minimise the risk of fungal diseases. Pelargoniums for example don’t like having wet leaves, which can lead to root rot and other issues.

Before watering, check soil moisture before watering by pushing your finger about an inch into the compost; if it still feels moist, hold off. Peat-free compost often dries on surface while remaining damp underneath, so don’t rely on appearance alone.

In hot weather, placing saucers under containers can help prevent water loss through runoff and grouping together pots creates a more humid, protective microclimate. Remember to remove the saucers during wet spells to avoid waterlogging and prevent roots from sitting in standing water.