Getting it to bloom

Why won't my Pirri-Pirri Bur bloom? (and how to make it flower)

Also called Pirri-Pirri Bur, Bidgee-Widgee, New Zealand Bur (Acaena novae-zelandiae).

More about pirri-pirri bur

About Pirri-Pirri Bur

Acaena novae-zelandiae · also called Pirri-Pirri Bur, Bidgee-Widgee · flowering

Pirri-Pirri Bur is a vigorously spreading, prostrate perennial from New Zealand with attractive bronze-green pinnate foliage and prominent red-spined burr heads in late summer. Excellent for low groundcover in sunny, well-drained spots. Note that this species is considered invasive in parts of the British Isles and must not be planted into wild areas.

Plant type: flowering

The reasons pirri-pirri bur isn't blooming

Almost every non-blooming pirri-pirri bur traces back to one of these, roughly in order of how common they are:

Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.
Too much nitrogen feed, driving lush foliage at the expense of flowers (very common with general or lawn feeds).
The plant has not been deadheaded, so it stops flowering once it sets seed.
Irregular watering — drought or waterlogging at the budding stage makes buds abort.
It is still too young or was checked by a transplant and is rebuilding before flowering.

Feeding pirri-pirri bur a high-nitrogen general feed and growing it in too little sun — you get a big leafy plant and almost no flowers.

The fix — how to get pirri-pirri bur to flower

Maximise sun. Give pirri-pirri bur the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers.
Switch the feed. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.
Deadhead regularly. Remove spent flowers often to keep it producing more rather than stopping to set seed.
Water consistently. Keep moisture even through budding and flowering — drought-then-flood swings make buds drop.

Light and feeding do most of the heavy lifting here. Dial in the spot with the light guide for pirri-pirri bur and get the feeding right with the pirri-pirri bur fertilising schedule — the wrong feed (too much nitrogen) is one of the most common silent reasons a healthy plant makes leaves instead of flowers.

Bloom season and what to expect

Pirri-Pirri Bur flowers across its growing season (mostly summer) and, kept fed and deadheaded, can bloom for many weeks or right up to frost.

Post-bloom care so it flowers again

Deadhead, keep feeding lightly, and many will rebloom; collect seed from the best plants at the end of the season if you want to grow them again.

For everything else this plant needs day to day, see the full pirri-pirri bur care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Pirri-Pirri Bur blooming — frequently asked questions

Why won't my pirri-pirri bur flower?

Pirri-Pirri Bur blooms on the season's growth given enough sun, warmth and the right feed — there is no cold or photoperiod trick, just good growing conditions and a bloom-leaning feed. The most common reason it is not happening: Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.

How do I make pirri-pirri bur bloom?

Give pirri-pirri bur the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.

When does pirri-pirri bur normally bloom?