Lime

Value to bees

Nectar

Very high

Pollen

Moderate

As a honey crop

Major honey crop — yields a surplus in good years

Which bees, and why

Worked intensely by honey bees, bumblebees and hoverflies. Dead bumblebees are sometimes found in numbers under flowering limes, particularly silver lime (T. tomentosa), and the popular explanation — that lime nectar is toxic to them — is not well supported. The better-evidenced explanation is starvation: the trees flower late in the bumblebee colony cycle, workers are drawn to a nectar source that is running dry, and they die of exhaustion under it.

Shallow open flowers with easily reached nectar, accessible to short-tongued and long-tongued insects alike.

Worth knowing

Extraordinary nectar productivity concentrated into a very short window. Its urban prevalence makes it disproportionately important to city beekeeping.

Flowering

In flower

June to July (northern hemisphere)

Around two weeks per species, but the different limes and hybrids are staggered, so a mixed avenue can yield for a month.

When nectar flows

Strongly diurnal and strongly weather-dependent — the flow peaks in warm humid conditions and can stop entirely in a dry wind. Lime is notorious among beekeepers for producing an enormous crop one year and nothing the next from the same trees.

Year-to-year variation

The most erratic major honey source in Europe. Lime is capable of filling supers in days and of yielding nothing at all in a cool or dry July.

What it does to the honey

Lime nectar gives the honey its unmistakable fresh, mentholated, almost medicinal lift — a cooling quality no other European honey has. That character is volatile and heat-sensitive, which is the practical reason lime honey should not be cooked.

Growing it

Conditions

Tolerant of most soils including chalk, and of urban air and hard pruning, which is precisely why it was planted along so many European streets.

Size

20-30 m.

Native range

Europe, from Britain and southern Scandinavia to the Caucasus. American basswood (Tilia americana) fills the same role in North America.

Suits

Large gardens, Hedgerow

• Too large for most gardens, but heavily pollarded street limes still flower once allowed a few years' growth — a lime pollarded annually flowers barely at all.
• Aphids on lime produce enormous quantities of honeydew, which is the sticky film on cars parked under them. Bees collect that honeydew too, so a lime can be a forage source twice over.

What it looks like

A large tree with heart-shaped leaves, and clusters of small pale yellow-green scented flowers hanging from a distinctive strap-shaped pale bract that acts as a wing when the seed falls. Small-leaved lime (T. cordata), large-leaved lime (T. platyphyllos) and the common hybrid (T. × europaea) all flower at slightly different times.