It is not new year resolutions that have had me thinking in the last few days. In a world that has spun beyond our control, resolutions seem a little… irrelevant. No. Since my post about the graveyard, I have been thinking about plant combinations.

I have a photo file of images loosely categorised under ‘plant combinations’. There are lessons to be learned from some of them.

Spot the problem with these two. These are pretty scenes based entirely on flower and colour combinations that we like. But, and it is a very big but, the flowering only lasts for a week to ten days every year. Many trees and shrubs have a very short peak time in bloom if you time them. We have plenty of such pretty scenes around our garden but we have a very big garden. In a smaller garden with limited space, most people want their plants to work harder over a longer period of time.

Hydrangeas are exceptions to the short blooming season rule and there are others but if you are setting out to plan for good combinations that are dependent on flowers, it is wise to check how long it is reasonable to expect the plants to actually bloom.

You can get longer in bloom from perennials than trees and shrubs. In practice, perennial gardening is heavily dependent on combinations. This pretty scene of Phlomis russeliana, Dietes grandiflora and Verbena bonariensis will last for a long time. And when the flowering is finished, the foliage combination will carry it through. That is the larger, flattish leaves of the phlomis contrasting with the grassy growth of the dietes, helped by how long the spent, candelabra flower stems of the phlomis hold on with their sculptural form.

Foliage matters. A lot. The graveyard photo of Stipa tenuissima and the burgundy ligularia is entirely dependent on foliage. So too is this scene of Curculigo recurvata and Ligularia reniformis. Foliage contrasts and combinations are what will carry the scene through the year. But, to be honest, foliage alone rarely lifts my spirits and makes me smile in the way flowers do.

Flowers and foliage work better. This combination of natives – Xeronema callistemon (the Poor Knight’s lily) and Pachystegia insignis (Marlborough rock daisy) looks interesting all year round but is particularly pleasing when the red xeronema or white daisy are in bloom, even though they flower in succession, not at the same time.

There are plenty of resources that will recommend good plant combinations but I never use them. It is much more fun to put your own together, even if you don’t always get it right first time. I thought my combination of a dark-leafed ornamental taro (black colocasia) and Dietes grandiflora in a low-maintenance planting for summer impact by our swimming pool would be brilliant. It wasn’t. The colocasia was so vigorous, thuggish in fact, that even the dietes didn’t stand a chance. I ended up removing all the colocasia because it was spreading at an alarming rate.

But sometimes it does work. A year ago I replanted this previously unsuccessful bed by our entranceway and I am pretty pleased with it. The dominant groundcovers are the two brown carex – upright Carex buchananii and the spreading Carex comans with a blue stokesia that blooms almost all year round. Autumn interest comes with a plum red nerine of Mark’s raising and towering self-sown Amaranthus caudatus, in late winter snowdrops and dwarf narcissi pop through, rhodohypoxis bloom in spring and I let the Orlaya grandiflora gently seed through. But it is the buff-brown carex and blue stokesia that carries it through all twelve months.

Putting plants together with both skill and flair comes with experience. Novices may line out plants in the garden centre, often based on flowers alone, and think ‘oh that looks nice. That’ll do.’ Experienced gardeners factor in a whole lot more variants. These variants will include the following:

• Plants need compatible growth habits. A vigorous thug will soon out-power a plant that is slower to establish or destined always to be of a more delicate nature. Plants with a spreading habit create shade and those with spreading root systems may swallow up their neighbours.
• Plants grow. It helps to consider how quickly and how large they will grow at the time of planning. Also, what their mature form will be.
• Plants need to like similar conditions – whether that be full sun or semi shade, sharp drainage or soils that never dry out or any of the other variants that contribute to a favourable growing situation.
• If you select plants for floral display, you have to accept that the beautiful combination so carefully crafted may be for a very brief time.
• Foliage contrasts give interest most of the year round. The most obvious contrast is spear-shaped foliage beside rounded, lush leaves or bold foliage with something light and fine but it can be more subtle. Variegated foliage is always best teamed with contrasting foliage that is a single colour. One lesson I have learned from our new Court Garden is that contrasts can be more subtle and still effective. All the foundation plants in that garden are selected for their ‘grassy style’ foliage and it is the other, more subtle variations that make the combinations effective – colour, movement, layering, and shape rather than foliar contrast. 
• A combination of both flowers and foliage will cover more bases in terms of complementary plantings and longer term visual interest.

Plant combinations can be quite simple but effective. It is the combinations that stops a large planting from looking like a Council traffic island or a utility supermarket carpark. Mark’s mantra bears repeating: “The world is full of too many interesting plants to want to mass plant a single variety.

The good news is that with time and experience, deciding on combinations becomes instinctive rather than an intellectual exercise in planning and is, for many of us, one of the best parts of gardening.