Mānuka

Value to bees

Nectar

High

Pollen

Moderate

As a honey crop

Major honey crop — yields a surplus in good years

Which bees, and why

Worked heavily by honey bees during the flowering, and by a range of native New Zealand insects that the honey trade has no interest in. New Zealand has no native honey-storing social bee, so the entire manuka industry rests on an introduced European species working an endemic shrub.

Open, shallow, fully exposed flowers accessible to almost any insect — the nectar is not hidden in a tube and short-tongued bees feed from it freely.

Worth knowing

A good nectar source during its brief flowering and of limited use outside it. A landscape of nothing but mānuka is a feast followed by a famine.

Flowering

In flower

November to January (southern hemisphere)

Southern-hemisphere summer, with regional variation of several weeks. The window is short — two to six weeks at any one site — which is why manuka beekeeping involves so much hive movement.

When nectar flows

Nectar dihydroxyacetone content varies enormously between individual plants and populations, and it is largely genetic rather than environmental. Two stands flowering identically can yield honey with completely different methylglyoxal potential.

Year-to-year variation

Highly weather-dependent and unreliable. Wind and rain during the short flowering can destroy a season, and yields per hive are modest even in a good year — the value is in the price, not the volume.

What it does to the honey

Mānuka nectar carries dihydroxyacetone, which converts non-enzymatically to methylglyoxal over weeks and months as the honey matures — which is why manuka honey's rating rises in storage while most honeys only degrade. The plant also gives the honey its damp-earth, medicinal, mineral character and its thixotropic gel, and none of that is shared with kānuka growing beside it.

Growing it

Conditions

Full sun, poor and free-draining soil, tolerant of wind and coastal exposure. Frost-hardy only to about -8 °C, which limits it outdoors in much of Britain and northern Europe.

Size

2-5 m, occasionally to 8 m.

Native range

New Zealand and southeastern Australia, including Tasmania.

Suits

Large gardens, Small gardens, Hedgerow

• A pioneer species: it thrives on poor disturbed ground and is outcompeted as taller vegetation closes over it. In New Zealand, mānuka stands are a stage rather than a permanent state.
• Garden cultivars are selected for flower colour and doubling. Double-flowered forms are largely useless to bees, which is the general rule for ornamental selection rather than anything specific to this plant.
• Nectar chemistry is not a garden-scale property. A mānuka in a European garden is a good ornamental shrub and will not produce methylglyoxal-rich honey.

What it looks like

A dense shrub or small tree with small, stiff, sharply pointed leaves that prickle when grasped, and masses of small five-petalled white or pink flowers with a dark red centre. The prickly leaf is the field mark that separates it from kānuka, whose leaves are soft.