Rosebay Willowherb (Chaemerion angustifolium, previously Epilobium angustifolium)
Rosebay Willowherb flowers from late June to August and is classed as a major plant source of nectar and pollen for honeybees, bumblebees and solitary bees. It is a tall herbaceous perennial with a spike of large pink flowers and the pollen is very distinctive being blue/green in colour. Honey produced from Willowherb has no distinct flavour and when crystallised is very pale and sets with a fine grain. The seeds produced are very light and feathery and drift for a long way in the wind. This enables it to quickly colonise areas such as demolition sites, freshly cut forestry sites and it can also found growing along railway embankments and many road side verges. When established it’s creeping underground runners enable it to spread rapidly and it may become a problem in some areas.
The plant has a fascinating flowering mechanism to avoid self-pollination. The first flowers to open are at the bottom of the flowering spike and the anthers (male parts) carrying the pollen mature early releasing the pollen and then shrivel before the stigma (female parts) are mature. The transfer of pollen from the younger flowers higher up the flower spike to older flowers with ripe stigmas lower down is reduced by the plant producing more nectar from flowers at this ‘female’ stage. This plant mechanism is called protandry whereas protogyny is where the stigmas mature first.
Lime or Linden (Tilia platyphyllos – Large leaved lime, Tilia cordata – Small leaved lime and Tilia x europaea – Common lime)
Lime trees are considered one of the major nectar sources for bees. Lime produces large volumes of nectar mainly in the morning before midday with the optimum temperature for secretion being about 20°C. Lime honey is said to be one of the most distinctive with a pleasant minty flavour and is light amber in colour with a greenish tinge. Flowers last for about 2-3 weeks and depending on site, soil, situation and species the flowering time can differ over several days, prolonging the length of foraging for our bees.
There are three limes which are native to the British Isles, Tilia platyphyllos (Large leaved lime), Tilia cordata (Small leaved lime) and Tilia x europaea (Common lime).
The common lime and large leaved lime are the worst offenders for honeydew which is the sugary solution excreted by aphids.
Large numbers of dead and dying bees can sometimes be found beneath some species of late flowering lime especially Tilia ‘Petiolaris’, Tilia tomentosa and Tilia ‘Orbicularis’. Research in the 1970’s suggested that the nectar was unusually high in a sugar called mannose. Bumblebees and honeybees are unable to digest it adequately because they have low levels of an enzyme that is important for the process. However, research in Germany in the 1900s and 2000s by Thomas Baal and others has contradicted this. No evidence was found for mannose in the nectar from trees with dead bees beneath them. Bees were most affected at the end of the lime flowering period or in dry years when there was very little nectar in the flowers. When bees below a tree were fed with nectar from the same tree, they were able to recover, so there was no evidence for toxic nectar.
Instead, the evidence indicated that bees were starving or running out of nectar and unable to fly back to their nest.
Apple (Malus domestica)
The apple is considered by beekeepers to be the best fruit tree as a source of nectar and pollen for bees. It is grown widely in gardens and parks and flowers over a long period from late April into May due to the many cultivars and varieties grown and is the last of the fruit trees to flower. Apple flowers have an open structure and nectar can be diluted or washed out by rain. This may be why bees can be seen foraging for pollen in the early part of the day and nectar later when the sugar concentration has increased due to evaporation and further nectar secretion by the flowers.
Daily nectar production between varieties of apple vary from 1.8 – 6.2mg of sucrose per flower.
A few apples are self-sterile but the majority require pollen from a different cultivar that flowers at the same time. Even those that are self-sterile fruit better in the presence of a pollinator.
Apple trees are sold as cordon, espalier, fan, bush, half standard or standard, so plenty of choice for either the large or small garden.
Norway Maple (Acer platanoides)
The Norway maple is a fairly fast-growing deciduous tree which can be seen all around the country side and in parks and large gardens. It reaches 25 – 30 metres in height and can be mistaken for the Sycamore but does not suffer from aphids. It has attractive greenish yellow flowers that appear on the bare stems well before the leaves, which appear about two weeks later, and it is an unmistakable tree to identify when seen in the countryside. The leaves are more brightly coloured than Sycamore and turn golden – yellow in the autumn. Some cultivars which can be seen growing in urban gardens are: Acer platanoides ‘Crimson King’ with purple foliage which turns bright red in the autumn, ‘Drummondii’ with variegated foliage, and ‘Columnare’ which has narrow upright growth.
All maples are good bee plants and supply nectar and pollen at an essential time for our colonies when building up for the summer. The open nature of the flowers enables honeybees, bumblebees and solitary bees to have easy access to the nectar.
Blackthorn (Prunus spinosa)
The blackthorn can be found at the edge of woodlands, in field hedgerows and reproduces naturally from its suckering growth and by the distribution of seeds by birds. The snowy white blossoms of blackthorn appear in February/March and contrast well with the black thorny leafless branches. It is not fussy about shelter and will grow on exposed sites and is often mixed with hawthorn when planting new hedges in rural areas thereby providing food and shelter for wildlife. The flowers are a good source of nectar and pollen which bees will take advantage of if the weather is favourable. The flowering season can at times be too early for honeybees to benefit from it but it can be visited by short tongued bumble bees and solitary bees such as the Tawny Mining Bee (Andrena fulva).
Cherry Plum (Prunus cerasifera)
The cherry plum or myrobalan plum flowers around the same time as the blackthorn and can be seen in gardens and is also used in hedge rows. In hedges it is often confused for the blackthorn but the white flowers appear on spineless branches.
A common popular cultivar of the cherry plum which is grown for its purple foliage and pink flowers in many gardens and as a street tree is Prunus cerasifera ‘Pissardii’. Both cherry plums are good sources of nectar and pollen for honeybees when the weather is suitable.
Hazel (Corylus avellana)
Hazels can be seen in flower from January to March depending on the area andlocationwhere it is growing. The hazel is wind pollinated and clouds of pollen can be seen drifting from the catkins on windy days. It does not need to rely on bees for pollination and fertilisation to produce the nuts. The hazel is common throughout the British Isles and grows best in calcareous soils where in the past it has been grown for coppicing and the stems used for wattle and daub building construction.
The plants produce no nectar and on warm days the large amounts of powdery pollen are collected by the bees on plants close to the hive. The catkins are available for about a month for thebees to forage on depending on weather and growing conditions. Pollen is vital for expanding colonies at this time of year providing the protein for growth and glandular development.
This is also the perfect time to take some goat willow (salix caprea) cuttings and grow them for future years as they will provide pollen early in the season.
Viburnum tinus ( Laurustinus)
Viburnum tinus is a popular evergreen shrub producing pinkish-white fragrant flowers over a long period from October to April.
It is a useful early pollen source for urban beekeepers and on fine warm spring days honeybees and bumble bees may be seen foraging for early pollen. It can be grown in most fertile well drained soil reaching a height of 2.5 metres but needs protection from cold drying winds. It can be used as a hedge or screen but can suffer problems from the Viburnum beetle.
Viburnum tinus responds vigorously to hard pruning and will break out freely even when cut down to the oldest wood near ground level. Shrubs that have been injured by a severe winter may be cut back hard in the same way. This pruning should be carried out in late spring.
Phacelia (Phacelia tanacetifolia)
Phacelia flowers are popular with honeybees and short tongued bumblebees and provide large amounts of pollen and nectar. Phacelia is a fast -growing annual flowering from April to November depending on when the seed is sown and with large numbers of flowers produced by each plant. Phacelia is not frost hardy but will survive in mild areas and pollen from its flowers is dark blue.
When sown in spring or early summer flowering commences within eight weeks and lasts for 4-6 weeks. Sowing at 4 weekly intervals will give all bees some forage until late in the year.
Phacelia is a good plant for improving soil and is widely grown as a green manure which is dug into the ground before flowering.
Stonecrop/Ice Plant (Sedum spectabile)
There are many different forms of Sedum that flower all through the year from ground hugging to 60cm high specimens.
The late flowering Sedum ‘Autumn Joy’ and ‘Brilliant’ with their grey green succulent foliage and flat- topped flowers are the ones which supply our honeybees and Bumblebees with late sources of nectar at a time of year when many other garden species are going over.
Sedums are easy plants to grow and will grow in most soils but when grown in moist rich ground flowers tend to flop over leaving an open centre. I find when planting them in less fertile ground in full sun the growth is hard and the flowers tend to be more upright and don’t flop over leaving an open centre.
Plants are easy to propagate by dividing in spring.
Himalayan balsam (Impatiens glandulifera)
The Himalayan balsam is an invasive non-native species in the UK. The Wildlife and Countryside Act 1981 Order 2010 prohibits planting or causing it to grow in the wild.
It is an introduced plant that first came to England around 1839 when it was grown in greenhouses for its flowers. It escaped into the wild and is now naturalised in most areas of the British Isles and can be seen growing in damp areas and along the banks of many rivers.
The flowers are various shades of pink or white and when the bees enter the flower whitish pollen from the anthers coat the thorax of the bee indicating to the beekeeper where the bees have been foraging and gives the bees the name of ghost bees. Himalayan Balsam flowers July to late into the year and provides the bees with a late source of nectar and honey for bees and beekeeper to harvest.
Germination takes place in Feb/March and plants can reach 2mt in height.
Blackberry (Rubus fruticosus)
The Blackberry is one of the commonest of wild plants and grows in any soil along country lanes, farm land and many gardens.
The flowers are produced on long main stems and short laterals and flowers over a long period between June to October which makes it a valuable plant to ho
neybees and bumblebees. The flower colour varies from white to light pink although white is the predominant colour.
Plants are deep rooted and drought rarely affects its ability to produce nectar.
Blackberry is a high fructose honey which is slow to granulate and not considered to be the best due to its coarse flavour and large granular structure.
It is attractive to bees and many other pollinating insects for nectar and pollen.
White clover (Trifolium repens)
White clover is one of the best plants for bees and produces large amounts of nectar when daytime temperatures favour nectar secretion. It flowers from June to September and each flower consists of 50-100 florets. The florets do not open simultaneously but in a sequence of circles and as the individual florets become pollinated, nectar ceases and the florets wither and droop. Clover grows best on alkaline soils but will tolerate a variety of soils.
Clover has the ability to fix nitrogen from the atmosphere and store it in the root nodules which is released when the plant dies. The nitrogen fixing properties made clover an important agricultural crop as the soil has less need for artificial fertilizers.
White clover has a shorter flower tube than red clover and the honeybee can easily reach the nectar with their short tongues. Red clover favours bumblebees with long tongues which can reach the nectar at the bottom of the longer flowers which short tongued bees cannot reach.
Cherry Laurel (Prunus laurocerasus)
The Cherry laurel and Portugal Laurel both flower between April and May and are attractive to honey and bumble bees for nectar and pollen. They are both common and can be found in many gardens forming shrubs, small trees or used for hedges and screens.
Flowers are produced on the previous years growth so any pruning to keep them tidy is best carried out after flowering has finished and new growth will then be produced to flower the following year. Bees can be seen visiting the plant at other times of year especially when nectar is scarce and can be seen foraging on extra floral nectaries on the underside of the leaf.
Portugal Laurel (Prunus lusitanica)
The Portugal Laurel is slower growing than the Cherry Laurel and can be used for topiary. It can be trimmed into standards or any shape but if you want it to flower only trim it after flowering. Both plants will tolerate sun or shade and will tolerate most soils.
Dandelion (Taraxacum officinale)
Dandelion flowers most freely early in the year and is a valuable plant to the bees, supplying nectar and pollen at a time when colonies are raising large amounts of brood. The pollen is light yellow and is produced in large amounts but contains low levels of amino acids which are essential for honeybee development. Dandelion pollen grains are oily, light yellow in colour and can appear as a deep orange on the corbicula of the worker bee. Dandelions flowering in orchards where bees are working the apple produce a richer nectar and may detract them from pollinating the fruit.
Flowers close during dull rainy weather which helps protect the nectar and pollen.
Beekeepers can obtain an early crop of honey from the dandelion but the honey is strongly flavoured and crystallises quickly.
Pussy Willow, Kilmarnock Willow (Salix caprea)
Willows range from small shrubs to large trees and are an important group providing nectar and pollen for bees. Depending on the variety and favourable weather, nectar and pollen can be available over a few weeks. The most common willow which grows along hedgerows, copses, railway embankments and woods is the Goat Willow. They are not fussy on soil conditions and are easy to grow with the most popular form being the Kilmarnock Willow (Salix caprea pendula) which can be found in garden centres at this time of year. Salix aegyptica is another variety which can flower as early as January and can provide a good source of forage if weather permits. In March pollen is essential for providing the bees with the protein to rear new young bees for the start of the season.
Willow can easily propagated with pencil thickness hardwood cuttings 8-10” long taken at the end of the year and planted close together in a slit trench to two thirds the depth of the stem. When rooted they can be lifted and planted where required.
Winter Heather (Erica carnea, Erica x darleyensis)
This is probably my favourite plant as it is reliably in flower from as early as late December to early May. Erica carnea and Erica x darleyensis will grow quite happily in alkaline or acid soils and on mild days bees readily visit the flowers mainly for nectar and some pollen. Flower colours vary from white to many shades of pink and red.
All heathers whether they are summer or winter flowering require some maintenance by cutting the old flower heads back to just below the bottom of the flowers around mid to late April. Following t
his procedure new fresh vigorous shoots will be produced and provide flowers of high quality the following season.
This keeps the plants compact and prevents them becoming straggly. Do not cut back into old wood as heathers will not regenerate.
Gorse (Ulex europaeus)
The common gorse is very thorny and not a plant some beekeepers would want to plant in the garden. Can be used for hedging, screens or as a single shrub in the border. Gorse tends to be in flower for most months of the year and is at its best around March/April where it is a good source of pollen for bees, helping colonies build up in spring. Gorse is drought resistant, grows in poor sandy soils and has the ability to fix nitrogen in the soil. It can be seen on many heathland areas where it can become invasive. If grown in rich soils it can become leggy and will need regular pruning to keep it compact.
It also provides protection, a good nesting habitat and safe haven for breeding small birds.
Other plants still providing some forage for bees if the January weather is favourable are, Mahonia, and some varieties of Viburnum.
Viburnum x bodnantense
Several related species of Viburnum are of value to bees for pollen on warm fine winter days. Frost resistant strong growing shrub with fragrant pink flowers appearing from late November to March.
Mahonia, Oregon Grape (Mahonia Aquifolium)
Mahonia is an evergreen shrub with holly like leaves that produces yellow racemes of fragrant flowers from November to March. Several species and varieties are available and in warm weather bees will work the flowers for nectar and pollen.
Large overgrown specimens can be cut back in early spring after flowering and will produce new growth that will flower the following autumn/winter.
Ivy (Hedera helix)
Ivy is an important source of nectar and pollen to honeybees at this time of year. Flowering late September to November and if warm enough flowers may still be found until late on in the year for bees to forage on. Pollen is consumed by workers in the autumn to enlarge the hypopharyngeal glands and fat bodies, allowing longer life of the winter bee.
Research has shown that honeybees going into winter with low levels of protein in their fat bodies have :
- Shorter lives.
- Are susceptible to Nosema and EFB.
- Don’t winter well and the colony is likely to suffer from spring dwindling as nurse bees require protein to produce brood food.
by Stuart Hatton