Blue Agapanthus

Blue agapanthus (Agapanthus praecox 'Blue') is the plant landscapers reach for when a large area has to look good with almost no attention. The evergreen clump sits at about 50cm high and 60cm across, and in summer it lifts rounded heads of blue flowers to around 1m. Planted 40cm apart it closes into a continuous band of foliage that flowers on cue every year.

Why you'll love it

• Blue flowers through summer. Big rounded heads on tall stems, held well clear of the foliage, and bees and butterflies work them constantly.
• It survives genuine neglect. Frost hardy, drought tolerant, salt tolerant and heat tolerant, which is a rare combination in one plant.
• Fast to cover ground. Fast growing clumps knit together within a season or two at 40cm spacing, which keeps weeds out.
• Green all year. The strappy foliage holds the line through winter, so a border still reads as deliberate when nothing is in flower.

Where it works best

Mass planting and driveways. Plant 40cm apart in blocks or a run along a driveway. At that spacing the foliage meets in the second season and the flower stems read as a solid line of blue.

Borders and edging. The same 40cm spacing gives a clean edge to a path or lawn, low enough not to block a view over the bed.

Pots and coastal gardens. It flowers happily when root bound, so a pot suits it, and the salt tolerance means an exposed seaside bed causes no trouble.

Growing blue agapanthus in Australia

Position and climate. Full sun gives the most flowers. Part shade produces good foliage and noticeably fewer heads. It suits warm temperate, cool temperate, subtropical and Mediterranean gardens, and it is frost hardy, so cold southern districts are no obstacle.

Soil. Almost any soil that drains, including poor and sandy ground. On heavy clay, raise the bed slightly and work compost through, since the fleshy roots rot in soil that stays wet all winter.

Water and feed. Water weekly through the first summer, then only in extended dry spells. Feed with a slow release fertiliser in early spring, and go easy on high nitrogen products, which push leaf at the expense of flowers.

Grooming. Cut spent flower stems off at the base, both for tidiness and to stop the plant setting seed, which matters in districts where agapanthus has escaped into bushland. Pull out old leaves in late winter, and divide congested clumps every four or five years. The sap irritates skin, so wear gloves.

What to expect when it arrives

It comes in three sizes: tube stock, 140mm pots in packs of ten, and 200mm pots in packs of six. Tube stock is the economical choice for a large area and usually flowers in its second or third season. The 140mm packs are the usual middle ground for a driveway run, while 200mm plants are established enough that many flower in their first summer.

Plants are packed to travel upright and delivered Australia wide, with delivery from $29.95. Every plant is covered by our 30 day healthy plant guarantee.

Plant care guides and related reading

• Browse the full agapanthus range
• Plants that suit mass planting
• How to choose edging plants for a garden bed
• Coastal and salt tolerant plants

Common questions

Is it safe around pets?

No. Agapanthus is not safe for cats and dogs, and the sap also irritates human skin, so wear gloves when cutting or dividing it. Choose something else if your pets chew foliage.

How many plants do I need?

At 40cm spacing you need about six plants per square metre, or five for every two metres of border. Wider spacing works but leaves gaps for an extra season.

Why is my clump not flowering?

The two usual causes are too much shade and too much nitrogen. A congested clump that has not been divided for years also drops away, so lift and split it in autumn or early spring.

Western Australia: this plant is listed as an environmental weed in WA, where it escapes from gardens into bushland. We do not recommend it for WA gardens. Please choose a local alternative.