Delphiniums

The Queen of the Classic Garden Border

By Ava Green

Tall, stately, and undeniably dramatic, the Delphinium or Larkspur is one of those perennial plants that stops people in their tracks. When given the right conditions, its towering floral spikes are magnificent. For gardeners who love a classic English border, nothing else compares. Yes, Delphiniums have lots of preferences, but tend to them, and they will reward you with a floral display that makes every bit of effort worthwhile. 

Choosing Your Delphiniums

With a wide number of varieties to choose from, there’s one that’s sure to fit every garden. Heights range from a modest 36 inches to an impressive 72 inches tall (Yes, 6 feet!), with a spread of 24 to 36 inches depending on the variety. So whether you have a compact border or a large sweeping bed, there’s a Delphinium to suit your space.

Their colour palette is equally diverse: rich blues and purples, soft pinks, crisp whites, and beautiful bicolours. Few flowers offer such a wide range. 

Planting

While Delphiniums prefer abundant moisture, be sure to plant the crown of the plant (where the stems meet the root ball) at soil level to avoid crown rot. Planting them too deeply is the most common way to lose these plants.

Spring and Fall are the ideal times to plant, giving roots a chance to establish themselves in cooler, more forgiving conditions. That said, a cool, overcast summer day works well too, just avoid planting during hot or humid spells. Spacing will depend on the variety you choose, so check the tag and give each plant the room it needs to breathe.  

Growing

Delphiniums are what gardeners affectionately call “Goldilocks plants”, they like things just right. Full sun, protection from strong winds, and fertile, humus-rich soil with excellent drainage are keys to success. They also love manure mixed into the soil to enrich their growing conditions. 

Their height is both their greatest asset and vulnerability. Because Delphinium flower stalks have hollow centres, they break easily if they’re exposed to the wind. Planting them in a sheltered spot is genuinely important. Once plants reach about 12 inches tall, stake each flower spike individually, or place a tomato cage around a clump early in the season before it’s needed. It’s much easier to stake proactively than to rescue a snapped stem after the fact.

Delphiniums are hungry plants and will perform best when fed generously. A dose of fertilizer, compost, or well-rotted manure in both spring and summer keeps them healthy and productive througout the season.

Finally, don’t overlook dividing. Each spring, simply dig up the plant and cut the root ball in half. Now you have two plants for your border, or one to keep and one to share!

The Show

All that care pays off in late spring and early summer, when Delphiniums put on one of the most spectacular displays in the garden. Tall, densely packed spikes covered in richly coloured blooms rise above the border like beacons. Bold, beautiful, and completely unforgettable. 

Once the first flush of flowers begins to fade, and before the blooms turn to seed pods, cut the spent spikes back to just above the foliage. This encourages the plant to produce a second, smaller flush of blooms later in the season and extends the show! As the old foliage fades, trim it away to allow the fresh new growth to replace it.

Inspiration

There are plants you fit into a garden, and then there are plants you plan a garden around. Delphiniums belong firmly in the second category. Their height, colour, and presence make them one of the most inspiring and rewarding perennials a gardener can grow.

Stop by Eising Garden Centre to see what Delphinium varieties we have available this season. Our team is always happy to help you find the right fit for your garden and set you up for success.