Plants for Bees by International Bee Research Association

“Our native bee population is under threat. This book offers a clear and practical guide to how anyone can create a bee-friendly garden. A wonderful and hugely important book.” — Kate Humble (television presenter and beekeeper)

PLANTS FOR

BEES A Guide to the Plants that Beneﬁt the Bees of the British Isles WDJ KIRK & FN HOWES

PLANTS FOR BEES WDJ KIRK + FN HOWES

PLANTS FOR BEES

CHAPTER ONE

WHY BEES NEED HELP NORMAN L. CARRECK International Bee Research Association, Cardiff, UK and University of Sussex, UK

This is a book about plants and their relationships with bees, so we need to begin by considering what bees are. There are about 25,000 species of bee found in the world, and around 270 species have been recorded from the British Isles. Of these, there is one species of honeybee (Apis mellifera), 27 species of bumblebee (Bombus species) and the remainder are solitary bees. These groups will be covered in more detail in Chapters 2–4.

Left: Honeybee visiting blackberry (Rubus fruticosus) (photo: C. Stevens)

ees are a group of insects closely related to ants and wasps in the scientific order Hymenoptera and it is thought that the common ancestor of both bees and social wasps was a kind of solitary wasp that was predatory on other small creatures and lived in the Cretaceous Period (146 million to 66 million years ago). In that period, when dinosaurs ruled the earth, flowering plants (angiosperms) began to appear, and it was at this time that some of these common–ancestor wasps became vegetarian and began to exploit the resources provided by this new type of plant. These vegetarian solitary wasps evolved to become bees. To begin with, all of these early bees still led solitary lives, each female bee making an individual nest, which she then provisioned with nectar and pollen collected from flowers as food for her developing young. Many bee species do this to this day, but some bees began to colonise good nesting locations in large numbers, forming aggregations, some then making common burrows (see Chapter 4). Eventually, some species developed a social lifestyle, with a dominant female laying eggs, supported by partially developed ‘worker’ females in the summer. This social behaviour is characterised by the bumblebees (see Chapter 3). A few species took this sociality even further, developing large colonies, which exist all year round, and produce a surplus of honey. Our honeybee, native to Europe, Asia and Africa, has been exploited by man for many thousands of years, and has been transported to all remaining parts of the world (see Chapter 2).

PLANTS FOR BEES

Left: Worker garden bumblebee (Bombus hortorum) showing its long tongue (photo: M. A. Kirk)

tongue, measuring a massive 13 mm – quite remarkable for a bee whose body length is only 11–16 mm. This means that garden bumblebees can access nectar even when hidden at the base of flowers with long floral tubes, such as red clover (Trifolium pratense), foxglove (Digitalis purpurea) and honeysuckle (Lonicera periclymenum). With a similar body-length, buff- and white-tailed species (Bombus terrestris and Bombus lucorum) are relatively shorttongued (approximately 7.5 mm). This means they are better suited to collecting nectar from flowers with shorter floral tubes. However, this does not stop these shorter-tongued bumblebees from getting to the rewards hidden deep inside the longer-tubed flowers. With their strong jaws, they are able to bite holes into floral tubes and steal nectar from deep inside. These ‘nectar robbing’ holes are then used by other short-tongued species such as the early bumblebee (Bombus pratorum) as well as honeybees, who act as secondary robbers.

Common, Rare and Recently Arrived Species Unfortunately, many of our bumblebee species are in decline, mainly due to agricultural intensification and associated loss of wild plants and nesting and hibernating sites and the increasing use of pesticides. Three species of ‘true’ bumblebee (the other species are ‘cuckoos’ – see below) that used to occur in Britain and Ireland are no longer found here, and a further eight have undergone serious decline in the last 50 years. Five of these rarer species have become the focus of detailed studies as a result of being listed as part of an internationally recognised programme addressing threatened species in the UK in the 1990s, and the other three have been studied as part of English Nature’s Species Recovery Programme. Despite this, our knowledge of the ecology of the declining species is still limited. Many of the declining species are long-tongued and it is thought that the reduction in long-tubed flowers, particularly red clover (Trifolium pratense), in the wider countryside has contributed to this decline. Although there are six species that can still be commonly seen in our gardens and are often referred to as the ‘big six’ (see opposite and Table 3.1), the real abundance even of these species throughout the British Isles is difficult to quantify. In fact, the ‘big six’ may actually incorporate eight species, given recent discoveries of species which look almost identical and may have previously been overlooked (Table 3.1).

CHAPTER THREE

PLANTS FOR BUMBLEBEES

The ‘big six’ widespread and common species of bumblebee

Far left: White-tailed bumblebee (Bombus lucorum) queen Left: Buff-tailed bumblebee (Bombus terrestris) queen (photos: T. C. Ings)

Far left: Early bumblebee (Bombus pratorum) queen Left: Red-tailed bumblebee (Bombus lapidarius) queen (photos: T. C. Ings)

Far left: Garden bumblebee (Bombus hortorum) worker (photo: W. D. J. Kirk)

Left: Common carder bee (Bombus pascuorum) queen (photo: L. A. Hislop)

PLANTS FOR BEES

CHAPTER FIVE

THE BEST PLANTS FOR BEES WILLIAM D. J. KIRK1 AND FRANK N. HOWES2 1

School of Life Sciences, Keele University, Staffordshire, UK

2 Formerly Royal Botanic Gardens, Kew, Surrey, UK

The plants described in this chapter can be grown to help bees. Detailed information is provided about them and their value to honeybees, shorttongued bumblebees, long-tongued bumblebees and solitary bees. A quick reference guide on p.285 shows the best plants at a glance.

Left: Worker buff-tailed bumblebee (Bombus terrestris) collecting pollen from the anthers of ﬂannel bush (Fremontodendron ‘Californian Glory’) (photo: C. Stevens)

The aim of this chapter is to provide detailed information about the plants that help bees. In it we hope to encourage those who can, to grow these plants in their gardens and conserve them in the wild in order to increase the number and diversity of bee species. This is not a practical gardening book; rather, we aim to give the keen gardener the information he or she needs to plan a bee-friendly garden. However, a useful and comprehensive guide to garden plants is included in the list of further reading and information (p.281). Similarly, this is not a bee identiﬁcation book and useful guides to help identify bees are also included in the list of further reading and information (p.281). The common bumblebee species are illustrated together in Chapter 3 (p.29) and some common types of solitary bee are illustrated together in Chapter 4 (p.43). Bees visit a vast range of plants, but there is only space in this book to cover a few hundred, so we have selected the best from those that are cultivated or grow wild in the British Isles. Inevitably, this choice is rather subjective and some good bee plants have had to be omitted, but we have endeavoured to include those that are of value to honeybees, bumblebees and solitary bees throughout the season. Nearly all the plants are of value for the nectar or pollen in the ﬂowers, but a few provide other resources too. For example, the leaves of lamb’s ears (see stachys) and rose provide nesting materials for some solitary bees and the stems of blackberry provide nest sites. The best plants are often those that are visited by many types of bee but there are also plants that are of particular value to restricted groups of bees, such as long-tongued bumblebees or certain specialist solitary

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PLANTS FOR BEES

Saponaria — Scabious

Saponaria — Vaccaria hispanica Family: Flowering: Cultivation: Honey: Honeybees: ST Bumblebees: LT Bumblebees: Solitary Bees:

Caryophyllaceae July to September annual herb no ||||| ||||| ||||| —

These garden annuals used to be grown much more than they are now. They can be raised easily from seed and may be listed for sale under the older name of Saponaria vaccaria. Two common varieties are ‘Pink Beauty’ and ‘White Beauty’. They produce sprays of pink or white flowers, each less than a centimetre across. They are sometimes visited by bees, probably mainly for pollen, and those sown in the autumn for early spring blooming are the most useful in this respect. Single-flowered varieties of the perennial soapwort (Saponaria officinalis) are also sometimes visited by bees, although the flower-tube is too long for nearly all bees to reach the nectar from the front. They can sometimes reach the nectar by poking the tongue between the petals from the side of the flower and short-tongued bumblebees can poke a hole at the base to rob the nectar. The doubleflowered varieties are of little value, as they have virtually no nectar.

Right: Flowers of saponaria (Saponaria ‘Bressingham Pink’) (photo: W. D. J. Kirk)

Saponaria — Scabious

Sassafras — Sassafras albidum Family: Flowering: Cultivation: Honey: Honeybees: ST Bumblebees: LT Bumblebees: Solitary Bees:

Lauraceae May deciduous medium tree no ||||| ||||| — —

This North American tree is occasionally seen in cultivation in the warmer parts of the British Isles, and is of interest because of the fragrant leaves and bark. It is the original source of ‘oil of sassafras’, which used to be used as a fragrance and flavouring, but is no longer used in the natural form because of the toxic effects of safrole in the oil. Its small greenish-yellow flowers, which appear in May for about two weeks, are visited by bees for nectar. Male and female flowers are borne on different plants.

Savory — Satureja montana Family: Flowering: Cultivation: Honey: Honeybees: ST Bumblebees: LT Bumblebees: Solitary Bees:

Lamiaceae June to July perennial herb no ||||| ||||| ||||| — —

Savory is one of the less common of the culinary herbs in British Isles gardens. With its strong ﬂavour it is sometimes used for seasoning, like thyme, and in France is traditionally cooked with broad beans in the same way as mint is cooked with peas. There are two sorts, summer savory (Satureja hortensis) an annual, and winter savory (Satureja montana) a perennial. Both are good honeybee plants and well worked for nectar, especially the latter. They ﬂower in June and July and have

CHAPTER FIVE

THE BEST PLANTS FOR BEES

235

pale white to lilac, rather insigniﬁcant ﬂowers. Bee stings have been traditionally treated by rubbing them with a sprig of summer savory to bring quick relief. Left: Honeybee on savory (Satureja montana) (photo: W. D. J. Kirk)

Saxifrage — Saxifraga species

S Family: Flowering: Cultivation: Honey: Honeybees: ST Bumblebees: LT Bumblebees: Solitary Bees:

Saxifragaceae March to June perennial herb no ||||| — — |||||

Left: Flower of saxifrage (Saxifraga ‘Southside Seedling’) (photo: M. A. Kirk)

Scabious — Scabiosa, Knautia and Succisa species The common name scabious is applied to several groups of closely related species (Scabiosa, Knautia and Succisa species). Wild and garden scabious are good nectar plants. The wild species are all freely visited by bees, especially the field scabious (Knautia arvensis) and devil’s bit scabious (Succisa pratensis), which occur in most parts of the British Isles. All have handsome blue or lilac flowers and are in bloom mainly later in the season. The secretion of nectar in the flower is of interest for it takes place on the upper surface of the ovary and is protected from rain by hairs in the flower-

Family: Flowering: Cultivation: Honey: Honeybees: ST Bumblebees: LT Bumblebees: Solitary Bees:

Dipsacaceae July to August perennial herb no ||||| ||||| ||||| ||||| ||||| ||||| ||||| ||||| ||||| ||||| |||||

Saponaria — Scabious

The saxifrages, wild or cultivated, are not among the best of bee plants, but honeybees frequently visit the flowers. The nectar is very exposed and only secreted in sunny weather when flies and other short-tongued insects have ready access to it. Such flowers are not usually great favourites with honeybees, perhaps because there are too many competitors for the nectar or they are too often disturbed. The same applies in the carrot family (Apiaceae) (see carrot). Among garden saxifrages, London pride (Saxifraga x urbium) is probably best known.

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PLANTS FOR BEES

Above: Queen buff-tailed bumblebee (Bombus terrestris) on willow (Salix species) See p.273. (photo: T. C. Ings)

281

A QUICK REFERENCE GUIDE TO PLANTS

A quick guide to the plants that are of most value to honeybees, short-tongued (ST) bumblebees, long-tongued (LT) bumblebees and solitary bees. Look down the column for a particular type of bee to see which plants are the best for it. The very best plants are indicated by a coloured symbol. Alternatively, look for plants with several symbols to ﬁnd plants of value to several types of bee. Plants in the Top 10 for a type of bee (see chapters 2, 3 and 4) are in bold. B

Colour key

Baby’s breath Balsam

Honeybees ST Bumblebees LT Bumblebees Solitary bees

Baptisia

Barberry Basil

Bearberry

Bee balm

00 00

00 00 00

Begonia A

Bellﬂower 00

Bilberry

Agrimony

Birch

Alder

Bird’s-foot trefoil

Blackberry

Black horehound

Blackthorn

Bloodroot

Anise hyssop

Bluebell

Anthericum

Borage

Box

Brassica

Broom

Buckthorn

Buckwheat

Bugle

Burning bush

Butterbur

Buttercup

Butterﬂy bush

Buttonbush

Achillea

Allium Almond Alsike clover Anchusa

Apple

Apricot Arabis Aralia Arnica

Ash Asparagus Aster Aubrieta Autumn hawkbit Avens Azalea

00 00 00

00 00

00 00 00

00 00

00 00 00 00

“Packed full of beautifully colourful images and written by experts this book provies a wealth of knowledge for gardeners, beekeepers and all those wishing to do their bit to help all species of bee”. — Norman Sellers, Wildlifeworld

It is widely known that our bee population is under threat and that honeybees, bumblebees and solitary bees are all in decline. Our own population growth directly impacts that of the bee as intensive agriculture and development for housing decimates the bees’ natural habitats. Our gardens are therefore fast-becoming an alternative home for many of our bee species and for our native bees to survive and thrive these spaces are crucial. Supported by contributions from leading experts in the ﬁeld this book is not just an information resource, it is also a practical handbook and a beautiful collection for anyone interested in bees and the valuable contribution they make to our lives.

Fiducias infeliciter corrumperet pessimus adfabilis umbraculi. Catelli spinosus miscere utilitas ossifragi, et saetosus syrtes agnascor matrimonii, ut rures corrumperet Medusa. Aquae Sulis praemuniet bellus matrimonii. Aegre tremulus fiducias imputat syrtes. Medusa optimus libere insectat concubine.