The perennial garden

Hillside Garden: The Perennial Garden

Let's look at how I've used structure, form, repetition and detail in my main perennial garden to create a cohesive swathe of naturalistic planting that blends with the landscape beyond.

The Emerging Structure of the Garden

As the garden matures, the first thing we're starting to see is the trees and shrubs emerging out of the perennial layer. The next thing your eye rests on is the volumes that form the greater weight in the planting – the emergent perennials. These include:

• Baptisia (false indigo) – a mound-forming perennial that's great for not needing division and that thrives on this dry, open hillside.
• Doellingeria umbellata (flat-topped white aster) – this forms a definite structure that still has air in it while providing a lovely counterpoint.

The weights of these signature perennials create important moments of structure and constancy, amongst which I can create a much more interwoven planting that comes and goes through the seasons.

Form and Repetition

Form is key in holding a perennial planting together. Those weights of Baptisia are the starting point, and I've picked up on those with Euphorbia ceratocarpa throughout the central section.

• This lights up the middle of the garden with bright lime green and holds your attention – it's a good colour for your eye to travel to. Also, this species has an incredibly long season.

Repetition is crucial in a planting because it provides cohesiveness. When putting a plant list together, I always ensure I have larger numbers of some plants so that they can be stepped up throughout a space.

• This helps your eye to travel through a space and allows it to feel like it's all one thing, rather than little collections of plants that feel busy and don't flow.

Repeated Vertical Elements

As a contrast to those dependable solid shapes, I've played with verticals. Verticals are also really important for providing repetition – almost like a quick succession of notes.

Using various different plants, these repeating vertical elements run right the way through the garden:

• Where I've got a flood of red coming down from the house, I'm using Persicaria 'Blackfield', whose upright flowers provide verticals through the rounded mounds of the Doellingeria.
• That's picked up further down with the tapering white flower spikes of Veronicastrum virginicum 'Album', which contrast with the darkness of the Persicaria. These take us right down the garden and over to the other side of the path to create repetition.
• Digitalis ferruginea, a tall rusty-coloured foxglove that is a biennial or short-lived perennial, seeds around to create a more dynamic vertical element, which I edit if necessary.

So although the verticals are similar in nature, they change through the colour use.

I've used verticals freely because they take up less space than wide plants. It also means you can repeat them, and through the froth of everything else, your eye can rest on something you recognise.

Detail Is Higher Nearer the Paths

Deeper into the beds, the planting is simpler because the eye travels over large spaces that you don't go into. The edges, which hold your attention as you walk along, are where you can work in the detail.

To create simplicity at the core of the beds, I've planted in larger groups, using swathes of Euphorbia ceratocarpa, Veronicastrum or Persicaria. This allows me to go into a lot more detail at the front:

• I underpin that detail with something like Stachys byzantina (lamb's ear), a silvery, felty-leaved ground cover that provides a sparkle at your feet and a contrasting backdrop for other plants.
• Amongst that, I've woven in oreganos, little alliums, and pinpricks of red from Potentilla 'Gibson's Scarlet' to keep the red moving through to the path.
• I've then got Dierama arching over the path to provide different verticals.

Creating a Veil with a Speckling of Tiny Flowers

I like to use plants with tiny flowers for several reasons. For instance,

1. It's easier to work with colour if you speckle it throughout multiple small flowers.

In this way, colour is repeated in tiny dots, almost like a pointillist painting. This means colour moves through the garden in a very delicate way and doesn't sit heavily. I've used these two plants throughout the planting:

• Scabiosa ochroleuca – a beautiful pale creamy scabious.
• Nepeta govaniana – a creamy catmint.

1. You can use these plants to create a gauze effect in the planting, with one colour emerging through another like a veil that you can see through. You can even see the landscape beyond.

Plants that are good for creating a gauzy veil:

• Sanguisorba, with its tiny drumsticks of colour in dark reds, bright pinks and whites.
• Verbena 'Lavender Spires'. This slightly thunderous colour is good to have in the distance because your eye doesn't immediately go to it, but when you find it, it creates a moody feel.
• Through this, I've interspersed a very dark Aconitum, whose larger, more solidly coloured flowers form a lovely dark weight inside the gauziness.

Self-Seeding

Digitalis ferruginea loves the warm, dry slopes and will seed around wherever it can find a niche.

• I tend not to use self-seeders in the perennial garden because they can be high maintenance, but since this is light on its feet and doesn't impose too much on other things, I'll let it spread.

So every year, there's a spontaneity introduced by the Digitalis, which contrasts with the constancy of the Baptisia, Doellingeria and peonies, and means that the garden is never quite the same year on year.

• In seeding around, they create unexpected combinations I hadn't planned for. If these aren't right, I adjust and take them out, but if they work, I go with it and claim that association.

Working with a Variety of Forms

Verticals are great as they create very definite points for the eye to rest on, but I'm experimenting with other forms as well:

• The arcs of Dierama are a counterpoint to those strong verticals.
• Pennisetum macrourum grass also has arching rods of flowers that will come over the path to echo the Dierama.
• Echinops (globe thistles) have a dramatic form with their round spiky globes of flowers.
• The spherical flowerheads of Eryngium (sea holly) are picked up by the 'Summer Drummer' alliums, which I've pushed through the vertical of the Veronicastrum.
• These globes are another repeat that continues throughout the garden, and your eye starts to read one with the other.

Forms are something you can really play with in a planting – it's important to remember to have fun when you're putting a planting plan together!

Planting with Consideration for Biodiversity

All the plants in the garden have been chosen with consideration for biodiversity. I'm not using double-flowered plants, I'm using plants that are a magnet for the local wildlife.

• The reason the garden is designed to start relatively late in the summer, and to run right through into autumn, is to provide a refuge for wildlife to come into after the meadows are cut.

Hemerocallis for Floating Colours

I love using plants that suspend their flowers on long, thin stems so that the colour and actual activity of the flower appears way above the foliage. Hemerocallis (day lilies) are brilliant for this.

• We've got red Hemerocallis 'Stafford' close to the house, and H. altissima and H. citrina further down, hovering amongst the euphorbias and Scabiosa ochroleuca.

Not being able to immediately tell where the flowers are coming from keeps a lightness in the planting. This airiness is key in allowing you to effectively use lots of plants close together without congestion or a feeling of heaviness.

I also create airiness using emergents. Some of my favourites are:

• Eryngium (sea holly), such as 'rattlesnake master' and E. agavifolium – their thimble-like flowers are punched high up in the air above a basal clump of foliage. They're also brilliant for wildlife.
• Umbellifers, such as Anethum graveolens 'Mariska' (florist's dill) – a nimble annual that again forms a basal cluster of leaves and then large flowerheads that soar up above everything else.
• I originally scattered some seed early in the season when there was still bare soil. It's now started to self-seed and come back every year without me needing to reseed.
• Cirsium (ornamental thistles) – these hold their flowers high in the air, free of everything.

You can pack a lot of plants into a small space without it feeling crowded by using emergents that have a small basal clump of foliage and then tall stems that take the flower up into the air.

Retaining a Naturalistic Feel to the Planting

To maintain a naturalistic mood when you're putting your palette together, it's important to think about the natural landscapes beyond or around your garden.

Here, the planting is inspired by the meadows and ditches and the plants that grow in those, such as wild angelica (Angelica sylvestris) and umbellifers, such as cow parsley (Anthriscus sylvestris).

• I've used a repeat of thistles, with three different types of Cirsium, to echo the thistles in the ditch further down the hillside.
• When you catch those bright colours of the Cirsium, you then pick them up again when they reappear down in the ditch. Again, these are brilliant for pollinators.

Plant Directory

• Baptisia
• Doellingeria umbellata
• Euphorbia ceratocarpa
• Persicaria 'Blackfield'
• Veronicastrum virginicum 'Album'
• Digitalis ferruginea
• Stachys byzantine
• Potentilla 'Gibson's Scarlet'
• Dierama
• Scabiosa ochroleuca
• Nepeta govaniana
• Pennisetum macrourum
• Echinops
• Eryngium
• Sanguisorba