Think of lime trees and the first thought that pops into most people’s heads is "don’t park underneath them" because of their unfortunate attractiveness to aphids, which then produce masses of sticky honeydew that drips onto the cars below and is difficult to wash off.
This is the fate of the common lime, Tilia × europaea, and the large-leaved lime, T. platyphyllos. But their tolerance of hard pruning still makes them both popular street trees.
It is not just aphids that are highly attracted to these trees. The most notable thing about the limes — or lindens, as they are commonly known — is how intoxicating their fragrant flowers are to bees.
While many species provide an excellent nectar source for honeybees, there are some that are said to be harmful to non-honeybees. This is believed to be because they produce nectar with sugars that cannot be broken down by certain types of bee, leading to true intoxication and sometimes death.
For those concerned about this effect it is probably best to avoid T. oliveri, T. × euchlora, T. dasystyla, T. tomentosa and its cultivars including ‘Petiolaris’ Award of Garden Merit (AGM) — plant T. platyphyllos and T. cordata instead.
There are about 45 species of lime, all deciduous trees from the northern temperate region. T. × europaea is a hybrid of the small- and large-leaved limes. It is known as the common lime because it is so easy to produce new plants from layering and therefore it has become ubiquitous. It is a large, vigorous tree often found planted in avenues and is known for its plentiful epicormic basal shoots.
The small-leaved lime, T. cordata, has heart-shaped leathery leaves and is very much part of the English landscape. It is found in ancient woodland sites because for centuries it was coppiced for the inner bark in its young stems from which rope was made. Some coppiced stumps are a whopping 16m in diameter and more than 2,000 years old.
T. platyphyllos, the large-leaved lime, is a significantly taller tree that has a wide canopy at maturity with branches that arch outwards and droop at the extremities. There are three recognised subspecies and several interesting cultivars including ‘Rubra’ AGM, the red-twigged lime; and ‘Laciniata’, with deeply cut and mutilated leaves.
Other limes of note include T. × euchlora, a lovely medium-sized tree with glossy green leaves and pendulous lower branches. Aphids do not become a pest with this tree. The silver lime, T. tomentosa, is another nice tree, although it has the narcotic effect on bees mentioned previously. It has white-backed leaves, which are resistant to aphids, and felted shoots. The straight species has a tendency for heavy spreading branches with drooping tips but there is a highly popular pendulous cultivar called ‘Petiolaris’.
Limes are easy to grow because they cope with all types of fertile soils and situations. They tolerate hard pruning so they have been widely used for roadside planting. However, the basal shoots do create a maintenance issue for councils.
T. platyphyllos is the first to flower in early summer, followed by the common lime, then T. cordata in late July. Limes suit "pleaching" — the effect created when trees are trained to grow towards each other on frames. T. × euchlora is a good tree for this type of training.
What the specialists say
Matthias Anton, managing director, Deepdale Trees, Bedfordshire
"Tilia are very good healthy trees, suitable for almost any soil type. They are an excellent choice for creating avenues and also as pleached, clipped trees for smaller gardens. Tilia are not that difficult to grow and will establish well and quickly on site.
"Some varieties can have aphid problems, which leads to honeydew dripping onto cars and the pavement below, creating a sticky mess. Limes that stay clean, not attracting aphids and therefore produce no dripping, include T. tomentosa, T. platyphyllos and T. × euchlora.
"The other species or varieties that stand out for me are T. × europaea ‘Pallida’, T. cordata ‘Greenspire’ and T. platyphyllos."
Stephanie Dunn James, assistant managing director, Trees for Life/Frank P Matthews, Worcestershire
"Tilia are noble, mythical trees. They are particularly suited to pollarding and pleaching due to their flexible soft shoots. Their delicate scented flowers make a quality honey and the wood is often used for making musical instruments, in particular guitars and wood instruments.
"They will thrive in almost any soil except the extremes of wet and dry. T. cordata ‘Greenspire’ stands out for me because it is a particularly good street tree."
Shelley Mosco, managing director, Green Graphite Landscape Design, London
"T. × europaea is one of my favourite street trees for its scent alone. I look forward to blossom time in June-July, when its perfume lifts my heart. Our local urban beekeepers also appreciate them because the bees produce delicious honey from them. The down side is the ‘litter’ left on the paths below afterwards.
"Limes are easy to maintain but it can be time-consuming. One of the problems with them are the sprouting ‘whiskers’, which are usually produced at the base of the trunk. They can be quite prolific but only need to be wiped off while they’re still buds. There is a new variety that is resistant to those shoots sprouting up."
Species and varieties
T. cordata, or the small-leaved lime, is a native tree to Europe and much of Russia. In Britain it is an indicator of ancient woodland because they have been regularly coppiced, with some specimens up to 2,000 years old. It becomes a columnar tree with heart-shaped leathery leaves and a greenish/yellow crown. Large inflorescences made up of scented ivory-white flowers appear in late July. Height: 24m.
T. cordata ‘Greenspire’ AGM is a popular cultivar for town parks and streets because of its narrow crown. It has upright branches, stands up well to wind and its fallen leaves rot down quickly.
T. cordata ‘Winter Orange’ AGM (H6) is a variety that has red buds and orange winter shoots. It produces ivory-white sweetly scented flowers in July and its leaves turn butter yellow in the autumn.
T. oliveri is an elegant, medium-to-large tree with smooth silver/grey bark. Closely related to T. tomentosa — similar leaves, toothed with silvery/white felted undersides. Does not attract aphids. Height: 20m.
T. mongolica, the Mongolian lime, is a small slow-growing tree with a compact rounded habit, making it ideal for gardens and confined spaces. Its glossy green leaves are produced on red stalks and have coarsely toothed edges and lobes like a maple or ivy. They turn bright yellow in autumn. Height: 10m.
T. platyphyllos, the large-leaved lime, is a large, spreading, round-topped tree native to much of Europe. Its leaves are sharply toothed and distinctly heart-shaped at the base. Height: 35m.
T. platyphyllos ‘Rubra’ AGM (H6) has a uniform, semi-erect habit because it is produced vegetatively, making it a good choice for street plantings and avenues. Its name refers to its bright brownish/red young shoots, which provide interest in winter. Height: 20-24m.
T. tomentosa, the silver lime, has white-backed leaves and felted shoots that are resistant to aphids. When mature it has heavy spreading branches with drooping tips. It produces masses of nectar that results in good honey. Some non-honeybees find it has a narcotic effect and drop from the tree, where they can get trampled or be predated.
T. tomentosa ‘Petiolaris’ AGM (H6), the weeping silver lime, is a large round-headed tree with a pendulous habit. It has white-backed leaves and richly scented flowers that have a narcotic effect on bees. Height: 30m.
T. × euchlora, the Crimean lime, has glossy deep-green leaves and pendulous lower branches. One benefit of choosing this lime is that its foliage does not attract aphids. Its nectar-rich creamy yellow flowers are highly attractive to bees, which get drunk on them. Height: 15m.
T. × europaea, the common lime, is a hybrid of the small- and large-leaved limes that has been cultivated since the 17th century. Often grown in streets, it is known for its basal epicormic shoots and attractiveness to aphids, which produce honeydew and sooty mould. Height: up to 45m.
T. × moltkei is a medium-to-large tree with arching, slightly pendent branches. A strong grower with broad leaves that are grey and downy on the underside. Large clusters of fragrant flowers are borne in July. Height: 22m.
Thank you to Floramedia, which supplied the images for this article from its photo library