7 tricks for full and beautiful delphiniums

A delphinium in full bloom is a breathtaking sight. Here are a few tricks for growing them in your garden.

Delphiniums, the royal cousins of larkspurs, preside over the garden with lacy, toothed foliage framing towering spikes of white, blue or violet flowers.

• Beloved in cool-climate gardens, where they will thrive with reasonable care, delphiniums are not suitable for regions with very hot, humid or arid summers.
• But where they can be grown, they should be grown.

Grow new plants from seeds sown in summer so that young seedlings won't have to endure summer heat.

• Delphiniums are naturally short-lived, so it's best to start new plants every other year.
• And, unlike many perennials, which must be propagated vegetatively, excellent hybrid delphiniums can be grown from seed.

Spoil their feet by providing them with rich, fertile soil that is deep, friable and well drained.

• Plenty of organic matter dug into the planting hole will help keep the soil moist during dry spells.

• Fresh air and dry leaves help prevent botrytis, a fungal disease to which delphiniums are particularly susceptible.

In damp weather, don't add to the plants' problems by wetting the foliage.

• For blooms all season on established plants, pinch out the growing points of some of the green spikes early in the season.

This will set back the flowering clock for the pinched spikes, but the unpinched ones will go ahead and bloom.

Many gardeners pinch only outer spikes so the central ones will bloom first. That way, the later blossom spikes hide the early ones as they begin to fade.

Tall giants fall hard.

• Begin staking delphiniums early, when they are only 30 centimetres  tall.
• Use a grow-through type of plant support that will hold up the stems when they are holding heavy blooms and a thunderstorm moves through the garden.

To enjoy a second flowering in September, cut back the stems of delphiniums as soon as the flowers have faded in June or July.

• Cut just above the basal leaves at a height of 10 to 23 centimetres.
• Water the plants copiously and apply liquid fertilizer several times throughout the course of the summer.
• When nights cool in early fall, watch for a fast flush of flower spikes.

Some people develop skin rashes from contact with delphinium sap, and delphinium foliage is moderately poisonous. That's why deer seldom nibble the plants.