How and why to plant in multiples, plus which plants to pair in your garden

SOMETIMES MORE IS better. Planting in multiples, often referred to as massing, creates excitement in a garden. I’m not talking about monotonous beds of single-species plantings but creating a composition with a limited community of compatible plants and going big on the numbers. How big? Of course, that depends on the size of your garden.

Richard Hartlage is founding principal of Land Morphology, a landscape architecture firm that designs and implements grand landscapes — think public gardens, private estates and artfully planted urban spaces. “We plant en masse when designing contemporary landscapes where the client is looking for simplicity and impact,” Hartlage says. Drifts of ornamental grasses underplanted with bulbs for seasonal interest figure prominently in these Land Morphology designs. “Only the most durable plants with multiple seasons of interest work in this scenario,” he adds.

You needn’t have a grand garden to make a big splash. My front garden is far from spacious, but that hasn’t stopped me from planting swathes of blue grama grass (Bouteloua gracilis); apricot sun rose (Helianthemum ‘Cheviot’); and a few small, rounded shrubs, like Berberis thunbergii ‘Concorde’ and a variety of heathers. The blooms of drumstick allium (Allium sphaerocephalon) bobble among the eyelashlike flowers on the grasses all summer.

Planting numbers are scaled to my small garden with groups of six, not 60. The color palette is limited, and the plants were selected for fine textures and continuing interest as well as having similar cultural needs. Filled with movement, blooms and colorful foliage, this bed looks good (can I say that?) throughout the growing season yet requires the least maintenance of any planting in my garden. I simply get to enjoy it.

Gardening in dry shade can be challenging. So why not simplify and repeat drifts of resilient plants, like bishop’s hat (Epimedium × versicolor ‘Sulphureum’), autumn fern (Dryopteris erythrosora) and black mondo grass (Ophiopogon planiscapus ‘Nigrescens’)? These drought-tolerant, nearly evergreen perennials can hold their own individually, but woven together, they form a dramatic ground cover that’s both beautiful and enduring.

Want more? I love coming up with plant recipes.

Furnish a broad planting bed with low mounds of fountain grass (Pennisetum orientale) among upright stands of switch grass (Panicum virgatum) and white Japanese anemones (Anemone japonica ‘Honorine Jobert’) for a pleasing and low-touch composition. Cut the plants back in late winter, and apply a fresh application of mulch to set the stage for a carpet of cheery daffodils. In late spring, flushing new growth on the grasses will fill in remaining gaps left by the bulbs. Pro tip: Deciduous grasses and daffodils are always a winning combo. Wiry stems topped with pure white blooms on the anemones appear midsummer into fall. A clump or three of beautiful regal lilies would add heavenly fragrance to the mix.

Don’t feel like you must limit mass plantings to herbaceous perennials. Generous swathes of ground cover roses create a tidy border or can fill a sloped site with continuous bloom. Roses not your thing? Nothing says summer like a long border of blooming hydrangeas. Panicle hydrangeas, also known as PeeGee hydrangeas, are easy and reliable. White conical blooms ripen to glorious shades of rose and wine as summer slips into fall. Unlike mophead hydrangeas, PeeGee hydrangeas bloom on new wood, averting any pruning concerns. Hartlage recommends Hydrangea paniculata ‘Little Lime’, a dwarf version of the popular ‘Limelight’, for its compact growth habit and extremely long flowering season.

Ready to try planting in multiples? At first it might seem restrictive to curtail your planting (and purchasing) impulses. Think of this planting strategy as an organizing framework, then layer in details as you wish.