Plants for Pollinators
Since the 1940's the UK has lost 97% of its flower rich habitats. One of the best ways we can all help Bee's and other pollinators is to increase the abundance of flowers for them to feed upon.
If you need help designing your planting project to benefit pollinators we can advise on the most suitable plants for your situation as well as designing and planting your space for you. We have links with many of the specialist plants for pollinators nurseries and seed distributors.
Scroll down to the bottom of this page for Downloadable guides on planting for bees
The relationships between Pollinators and Plants
Pollinators and flowers go hand in hand, we cannot have one without the other. Pollinators are the vector by which the plants achieve fertilisation thought the transfer of pollen from the male part of a flower to the female part of another flower. For the pollinators the flowers represent their food source.
This relationship between insects and flowers began over 160 million years ago when the first flowering plants evolved. At first these simple flowers did not produce nectar but were pollinated by Thrips and Beetles which visited the flowers to eat the nutritious pollen. The plants learnt that they could entice insects to transport their precious pollen grains to flowers of neighbouring plants by secreting excess sugars in the form of a nectar.
This triggered an evolutionary arms race with plants developing ever more elaborate methods of attracting pollinating insects to their flowers including the use of scent lures and for the insect’s ever more efficient adaptations for transporting pollen and accessing the nectar presented to them. Even today beetles represent the largest group of pollinating insects on the planet by sheer numbers and are responsible for pollinating 88% of the world’s estimated 240,000 species of flowering plants.
The first Bees appeared around 100 million years ago with Bumble bees and Honey bees evolving in the last 30 million years. Bees are more efficient pollinators of flowers than many other insects due to their unique ‘plumose’ hairs which cover their bodies. These branched hairs are more efficient at clinging to pollen which the bees can then transport to an unrelated flower to achieve pollination.
Flowers offer food for pollinators in 2 forms.
Nectar:
Many plants secrete nectar from glands which the insects feed upon. Nectar is rich in soluble sugars which are simple carbohydrates and give the insects the energy they need for their metabolic activities. Flying is an energy demanding activity which means many insects spend a great deal of time flying from flower to flower in search of nectar. Nectar also contains trace elements, vitamins and micro nutrients needed to maintain healthy body functions.
Not all plants produce nectar (many early spring and winter flowering plants can’t create soluble sugars in cold temperatures) and some plants produce nectar in greater abundance than others. Some nectar sources also contain more sugar than others which can make them more appealing to pollinators.
Different pollinators have different lengths of tongues which means not all species are attracted by the same flowers. Those with shorter tongues will be better adapted to access nectar on simple open flowers which shallow nectar wells whilst long tongues species are better equipped to take advantage of flowers with long trumpet shaped structures.
Many plants have specific requirements which must be fulfilled before they will produce nectar. These can be dependent on climatic variables such as temperature, exposure to sunlight, moisture content of the soil and air humidity.
For this reason it’s important to plant a wide variety of flower types to cater for the widest range of pollinators.
Pollen:
Pollen is the small capsules of genetic material from the male part of the flower which inseminates the female ovaries of another flower. Pollen is high in Protein, amino acids, fatty acids and contains many nutrients. Insects consume pollen for its high nutritional value to aid in body repair and tissue growth.
Bees which are entirely vegetarian collect pollen to feed t their developing larva. The pollen contains all the protein and nutrition the larva need for growth and development.
Different plants produce different quantities of pollen and some produce pollen which is greater in protein than others. Many solitary bees specialise on collecting pollens of only a few select species of plant which cater for their specific nutritional requirements, whilst Honey bees will collect pollen from a very large number of plants.
Above: A Red Tailed Bumble Bee worker collects pollen from a corn flower
When do pollinators need access to flowers?
Pollinators are at their most abundance and most active during the late spring and summer months and in winter many either hibernate or migrate to warmer climates. Some pollinators such as Buff Tailed Bumble Bees are active 12 months of the year and therefore need flowers all year round.
In spring when pollinators are emerging from their long hibernation they need to seek out flowers urgently so that they can feed and build up their bodies to breeding condition. For Bumble bees this means seeking out pollen rich sources of forage such as legumes and members of the Laminacea. Honey bees resume brood rearing very early in the year before most plants are able to produce nectar. They survive off their honey stores until late spring but during early spring need large volumes of pollen to feed to their growing brood nest.
Later into spring nectar becomes more important for bees as the adults are growing in numbers and for honey bees it’s a race to lay down enough honey to get them through winter before the end of summer.
Many pollinators struggle to find enough flowers in late summer to survive on. This is because many of the UK’s grassland flower species have evolved in a cut for hay regime over many thousands of years and have adapted to complete flowering and setting of their seed before the summer hay cut. Most of our woodland plants have evolved to flower very early in spring before the leaves emerge on the woodland trees and shade them from the sunlight.
Late summer is a crucial time for many of our pollinators. At a time when there is a reduction in flower availability many pollinators are desperately trying to lay down enough energy reserves to ensure they survive their winter hibernation. One of the best ways to help pollinators is by planting late season flowering plants that will help them survive the summer dearth in forage.
What sources of forage are most important for London’s Honey bees?
Urban bees have access to a wider diversity of plants than their rural cousins due to the presence of both native plants and the wide range of exotic species grown in the city’s parks and domestic gardens.
Many of the plants important to urban bees are plants also important to rural bees but several exotic species are of particular importance to city bees.
Trees in particular are very important to pollinators especially Honey bees. A large mature tree can contain as many blooms as an acre or more of meadow flowers making them a valuable forage resource.
In Urban areas where green space is at a premium trees represent value for money and pollinators as they take up little space on the ground but have wide ranging benefits to both wildlife and man.
Shrubs are also important. Later in the season low growing plants become more important as trees and shrubs finish flowering and set their seeds.
Above: Lime and Horse Chestnut are valuable sources of forage for bees.
The best garden plants for bees
Not all flowers are equally attractive or beneficial to bees and other pollinators. Attractiveness and benefit to pollinators varies a great deal with some plants being 100 times more attractive and useful than the worst. To complicate things not all plants are equally beneficial to all insects due to the shape and morphology of the blooms which may prevent all but a few dedicated visiting bees whilst others contain toxins which only certain species of bee are immune to the effects of. Great examples are the foxglove Digitalis Purpurea, Comfrey Symphytum officinalis and Everlasting Pea Lathyrus latifolia which are among the top 10 UK plants for Sugar content in their nectar and the amount of nectar produced per hectar (kg of sugar/ha/year). These 3 plants should be a magnet for all bees having the greatest rewarding nectars among British Plants. However Fox Glove and Comfrey are plants with deep tubular flowers which prevent all but the longest tongues from accessing their nectar meanwhile Everlasting Pea has both a deep nectary and tightly lipped flowers which require a long tongued bee with a robust body to enter.
Bulking up your gardens by planting the most attractive and beneficial plants for a broad range of insects will provide the most benefit to pollinators whilst adding plants which are attractive or of benefit to only a small number of species helps provide food for more fussy specialists. There are many bees which are not generalist and will only feed their offspring pollen from a small number or a single species of plant. Plant a mixture of broadly attractive and specialist plants and choose plants which will offer flowers over a long season or plan a succession of flower types throughout the season.
Examples of some of the best plants to attract a broad variety of pollinators are listed in the table below available as a downloadable PDF file.
For more information on what flowers to plant for pollinators download our fact sheets below
These information guides are not exhaustive in listing plants valuable to bees but point out some of the more important ones to bees including garden plants attractive to bees. These guides are based on a combination of recently published research into pollinator flower preferences and our own observations, monitoring which species use flowers commonly found in urban environments.