Trees with Insect-pollinated Flowers

Many trees are planted for their spring blossom, providing a splash of colour in an otherwise still rather drab post-winter landscape. All trees have flowers, either insect or wind-pollinated, but insect-pollinated flowers are larger and more showy: if the flowers appear plain white, they are usually richly patterned in the ultra-violet wavelengths visible to insects. It is not always visually clear whether a flower is insect-pollinated or not, but the presence of often strong-smelling nectar provides confirmation. Below are images of ten such insect-pollinated trees.

Wild Cherry (Prunus avium)

When one thinks of trees and flowers, the blossom of Japanese cherries immediately springs to mind. Japanese cherries are carefully bred and selected cultivars, nearly always grown by grafting onto a rootstock of Wild Cherry. In the British countryside Wild Cherry is the only large-flowered large woodland tree.

Common Hawthorn (Crataegus monogyna)

In May, after the Myrobalan Plum and the Blackthorn have finished blossoming, hedgerows are dominated by the white flowers of hawthorn. Cherry, hawthorn, and the majority of other native (or naturalised) British trees with insect-pollinated flowers are members of the Rose family.

Red Horse Chestnut (Aesculus x carnea)

The flowers are arranged in vertically-held 'candles', similar to the familiar white 'candles' of the the more common Horse Chestnut. In both cases, close up inspection of the flowers reveals a rich range of colours besides the base white or red coloration.

Lilac (Syringa vulgaris)

Depending on how you define a tree, lilac may or may not make the cut, and might just be considered a large shrub. Regardless, its flowers are not only prominent, but well known for their rich scent.

Elder (Sambucus nigra)

This is a native tree, more commonly seen as a large bush, which has large umbels of strongly-scented white flowers. Nectar production ramps up on sunny days, which is when they should be collected for elderflower cordial.

Silver Lime (Tilia tomentosa)

Small-leaved and Broad-leaved Limes are native to Britain; much more frequently seen, both in the town and countryside, are planted Common Limes, a hybrid of the two which is easy to propagate from the abundant sprouts which rise from the trunk base. All limes, including the rather more elegant Silver Lime pictured, have white flowers with rich nectar which is actually toxic to some insects.

Manna Ash (Fraxinus ornus)

Curiously the Fraxinus genus of ash trees contains both insect- and wind-pollinated species. Manna ash produces rich swathes of flowers colouring the whole tree white, and therefore looks very different in flower from the wind-pollinated Common Ash with much smaller flowers.

Tulip Tree (Liriodendron tulipifera)

A large number of species have been introduced into Britain particularly for their striking flowers. The Tulip Tree is a handsome large tree first grown in the UK in 1685, not only with large tulip-like flowers, but also strange-shaped leaves.

Strawberry Tree (Arbutus unedo)

Another widely-planted species, actually native, but only to the extreme west of Ireland, is the Strawberry Tree, with delicate lily-of-the-valley like flowers and fruit which only very vaguely resemble strawberries (and as the Latin indicates are inedible).

Spindle (Euonymus europaeus)

And finally, the Spindle is a widespread native shrub or small tree, so named because its hard wood was used for skewers and spindles. The flowers are somewhat understated, but are more than made up for by the unique two-toned fruit.